Archaeological Basketry Treatments

 Table by Dana K. Senge and Ellen Carrlee, updated May 2010

Most recent version to be seen at Dana’s website: http://waterloggedbasketry.blogspot.com

Reviewed by Kathryn Bernick, May 2010

table for pdf

Site	Treatment	Condition Notes
Site: Alouette Basket Site (DhRp 19)Date recovered/treatment:Location of Collections: RBCM[1]  Materials: warp: red cedar branch or trunk, weft: spruce root, IDs by ML Florian (Bernick:1991) Age:   Burial Conditions: “a film of blue-grey clay covers the elements indicating that it was once buried in the type of matrix characteristic of wet sites” (Bernick 1991, pg 110) Deterioration:	SOLVENT DRY“…immersion for one week in 10% ethanol, then increasing proportion of ethanol by 10% every week for 10 weeks (until reaching 100%)…  slowly dried between sheets of plate glass…”  (RBCM Conservation Lab records: 2629)	1991: “Wood elements rigid and apparently stable”.  (Bernick 1991, pg 111)2010: To date the authors have not examined the basketry material from this site.
Site: Axeti (FaSu 1)  Date recovered/treatment: 1969-72Location of Collections:  Museum of Archaeology and Ethnology, Simon Fraser UniversityMaterials: inner bark from western red cedar, root and splints. Age: 1500 –1710 years +/- 80  Burial conditions: Deterioration:	PEG TREATMENT % MW: 10% solution of PEG close to 4000 Duration: immersion varied from several weeks to three months depending on density of artifact.Heated? No  Drying: Air-Dried (Hobler 1976)	2010:
Site: Beach Grove (DgRs 1)Date recovered/treatment: 1962Locations of Collections: LoA of UBC[2]Materials: No reference found identifying material types or species thin wood splints, likely red cedar (Bernick 2010)  Age: Age of water-saturated component: 1603 years old +/- 120 Burial Conditions: stratum of finely textured silty clay of bluish-grey color below watertable (Fraser delta alluvial deposits, anaerobic) Deterioration:	One fragment of basketry treated in field by the archaeologists and block-lifted on slab of mud; no further treatment of the basketry (Bernick, 2010).Others were treated with applications of Houston No. 3 Preservative supplied by the B.C. Provincial Museum (now RBCM) and “Firewater”“…excavators preferred the Firewater because it hardened the punky wood…” (Bernick 1991, pg 113)	1991: “…artifacts are shrunken and brittle, and, in most cases, the wood has severely checked…basketry was block-lifted-… still firmly set on a slab of mud” (Bernick 1991 pg 113).2010: To date the authors have not examined the basketry material from this site. Upon the recommendation of collection manager at LoA of UBC requests were made in 2008 and 2009 to the Tsawwassen and Musquem Bands for permission to examine and possibly sample material from the collection were unanswered.
Site: Biderbost  (45 SN 100)Date recovered/treatment: 1959-early 1970s/likely treated immediately upon recoveryLocation of Collections: Burke Museum[3] Materials: wood splints, presumed to be western red cedar withes or roots  Age: ca. 2000 BP Deterioration:	COAT WITH ADHESIVEPainted or soaked in a solution specially prepared (25% Plyamul Adhesive #9153- polyvinyl acetate soln from Reichold Chemical (now Forbo) and 75% Firewater (50cc heavy detergent of Firewater Company of Los Altos)  (Nordquist:1976)	2009: Material is dark brown, dry in appearance.   Some spots of surface sheen from adhesive.  Dirt glue to surface of inner bark elements.Elements are rigid but have some flexibility, not brittle with minor pressure.
Site: Blundell Road Basket (DgRs 15)Date recovered/treatment: 1967Location of Collections: LoA at UBC Materials: wood splints, likely western red cedar withe Age: 2180 +/- 170 BP (direct date on the basket) Burial conditions: find site: 4 feet deep in sphagnum peat, probably a slough when originally deposited (Bernick:1991) Deterioration:	AIR DRYBasketry was not treated with any preservative. (Bernick 1991, 114)	1991: “wood is now brittle and somewhat shrunken.  Matted sphagnum moss… still adheres to large portions of the surfaces”. (Bernick 1991, pg 114).2010: To date the authors have not examined the basketry material from this site.
Site: Castle Hill (49-SIT-002)Date recovered/treatment: 1995-1998Location of Collections: Alaska State MuseumMaterials: likely spruce root Age of Collections: ~ 700 radiocarbon years Burial conditions: Deterioration: Little deterioration	AIR DRYNot fully waterlogged when found, only slightly damp. Basketry slowly air-dried in fridge for several years, exact time it took to dry unknown.(Alaska State Museum treatment records)	2009: Stable. Can be safely handled and turned over for examination.
Site: Conway wet site (45 SK 59b)Date recovered/treatment: 1970Location of Collections: BurkeMaterials: some entirely cedar bark, some eintrely wood splints (likely cedar withes), some a combination (Bernick 2010) Age of Collections: ~ 700 radiocarbon years Burial conditions:  anaerobic alluvial deposits below watertable in Skagit River delta; a slough when originally deposited;   Deterioration:	PEG TREATMENTMaterials were soaked in ethanol (95%) for two days, then:% MW: 33% PEG 1000 Duration: 2-4 days  Heated? No Drying: Air-dried on racks for 1-2 weeks (Munsell 1976)	1976: recommend subsequent retreatment since basketry appears dry. (Munsell 1976)2009: Color variations from red-brown, black and light grey.  Light grey from remaining soil matrix. Some have a great deal of variation in tone, others all black.  Basketry materials dry in appearance (not waxy, saturated etc).Materials are stiff with some flexibility on in the elements.
Site: Cowichan Bay Site Date recovered/treatment: ~2000Location of Collections: possibly RBCMMaterials: Age:   Burial conditions: Deterioration:	AIR DRYAir dried following excavation.  Sent to CCI to see if condition could be improved.  Currently at CCI. (Confirm?)	2010:
Site: DgRs 36Date recovered/treatment: 1990’s Location of Collections: possibly at UBC?Materials: Age: ca. 2100 years old Burial conditions:  found in back dirt pile possibly came from same location as Water hazard (DgRs 30)  Deterioration:	Possibly treated at RBCM% MW: Duration: Heated? Drying:	2010:
Site: DhRq 19Date recovered/treatment: 1990-93 Location of Collections: Materials: western red cedar inner bark and limb/root Age: radiocarbon dates average ca. 900 BP Burial conditions:  found eroding out of the Fraser River beach in a tidal environment.  Deterioration: The materials looked to be in good condition when found (Bernick 2010)	Possibly treated at RBCM% MW: Duration: Heated? Drying:	2010:
Site: DgRn 9Date recovered/treatment: 1960’s Location of Collections: RBCMMaterials: western red cedar splints Age: style indicates it is 2000 years old Burial conditions:  found eroding from Fraser River Beach in Fraser Valley   Deterioration:	Possibly treated at RBCM ?No treatment records?Each fragment appears to have been treated using a different method? (Bernick 2010)	2010:
Site: Ditidaht Sites DeSf 9 and DeSf 10Date recovered/treatment: 1994 Location of Collections: RBCM (requires permission of Parks Canada, Ditidaht First Nation and RBCM)Materials: western red cedar inner bark Age: ca. 600 BP Burial conditions: Deterioration: (Bernick 2010)	Treated at Parks Canada in Ottawa (contact for treatment information)% MW: Duration: Heated? Drying:	2010:
Site: English Camp Site (45 SJ 24)Date recovered/treatment: 1971 Location of Collections: Burke MuseumMaterials: 2 basketry artifacts: one is a basket fragment of wood splints, likely western red cedar withes;  the other is a hat possibly of western red cedar inner bark (Bernick 2010). Age: ca. 2000 years old (Sprague 1976) Burial conditions:  anaerobic water-saturated deposits at bottom of shell midden  Deterioration:	PEG TREATMENT% MW: 50% Carbowax (PEG) 1500  in water.   Duration: No mention of timeHeated? No  Drying: No mention of drying technique, likely air-dried. (Sprague 1976) (Note:  PEG 1500 used in treatment may now be 540 Blend due to name change in mid 70’s)	2010: Basketry has a dry brown appearance.  Materials are delicate with little flexibility.
Site: Fishtown (45 SK 99)Date recovered/treatment: 1974Location of Collections: Swinomish Indian Tribal CommunityMaterials: species IDs has not yet been performed Age of Collections:1220 years old +/- 70 years Burial conditions:  water-saturated anaerobic deposits  Deterioration:	PEG TREATMENT % MW: 50% polyethylene glycol 1500 in water Duration: 4 weeksHeated? No  Drying: Air-dried.  (Blukis Onat 1976) (Note:  PEG 1500 used in treatment may now be 540 Blend due to name change in mid 70’s)	2009: Request to examine collections respectfully declined due to lack of protocol in collections policy.
Site: Glenrose Cannery Site (DgRr 6)Date recovered/treatment: recovered 1988 & 1990, treated in 1991Location of Collections: LoA at UBCMaterials: collection contains cherry/maple bark; fir-wood splints (Abies) and cherry/maple bark (true bark) with cedar splint elements and salmonberrty element.  IDs by M-L Florian (reported in Eldridge 1991) Age: 4300 BP Burial Conditions: water saturated anaerobic deposits in Fraser estuary; deposit lies just underneath beach pebbles, consists of layers of grey and coarse sand with crushed shell. (Bernick1991)  Deterioration:	PEG TREATMENT % MW: 10-20% aqueous soln of PEG (no MW recorded), but possibly PEG 540 Blend Duration: (no time recorded). Heated?: No  Drying: Possibly freeze dried and consolidated with Rhoplex 33.  (Erling 1991)	1991:“basketry is waxy and generally dark-colored” (Bernick 1991, pg 119)2010: To date the authors have not examined the basketry material from this site.
Site: Hesquiat Harbor ( ) Date recovered/treatment: Location of Collections:  RBCMMaterials: wood splint baskets Age: 100-200 years  Burial conditions: Deterioration: materials removed damp not waterlogged.	AIR DRIED
Site: Hoko Complex (45 CA 213)Date recovered/treatment: began in 1973Location of Collections: Makah Cultural and Research CenterMaterials: limb, inner bark, no reference found identifying species  Age: 2500 year old fishing camp (Croes 1976, pg 88)  Burial conditions:  anaerobic desposits along riverbank, Hoko River estuary  Deterioration:	PEG TREATMENT Artifacts recovered in 1967- 50% white glue treatment.% MW: Artifacts recovered in 1973—treated with 50% PEG 1500Duration: 4 weeks Heated? No Drying: Air dried (Croes 1976) (Note:  PEG 1500 used in treatment may now be 540 Blend due to name change in mid 70’s)	2009: While most of the Hoko River materials seem darkened by not waxy the artifacts do range visually from dry (315/AL/4 ) to saturated/waxy surfaces (ACQ 910909).
Site: Kanaka Creek basket  Date recovered/treatment: 1991Location of Collections:  Museum of Archaeology and Ethnology, Simon Fraser University (1992.004.001)Materials: cedar root (Winter 2010) Age:   Burial conditions: fine grained fluvial deposits on the north bank of the Fraser River. A large lump of silty sand coated and supported the basket. Deterioration:	PEG TREATMENTArtifacts were rinsed to remove mud and silt, then% MW: 20% PEG 400 for 15 weeks then 6 months of 20% PEG 400 + 4% PEG 4000Duration: 9.5 months Heated? No Drying: Air dried, then couriered to CCI where it was freeze-dried.	2010:
Site: Lachane Site (GbTo 33)Date recovered/treatment: 1973 Location of Collections: Canadian Museum of Civilization, Gatineau, QuebecMaterials:  26 baskets are cedar bark, 1 is “inner alder bark” (Croes 1989)   Age: 1600-2500 BP Burial conditions: watersaturated anaerobic deposits; matrix resmbled peat (Inglis 1976)  Deterioration:	PEG TREATMENT % MW: 10% PEG 1500 for three months, 25% PEG 1500 for three months, 50% PEG 1500 for three monthsDuration: Nine months Heated? No  Drying: No mention of drying technique, likely air-dried (Inglis 1976) (Note:  PEG 1500 used in treatment may now be 540 Blend due to name change in mid 70’s)	2010: To date the authors have not examined the basketry material from this site.
Site: Little Qualicum River Site (DiSc 1)Date recovered/treatment: 1972?, 1974,1976 Location of Collections: RBCM Materials: western red cedar (all 21 basketry artifacts, all fragmentary): Some are entirely cedar bark, some entirely withe splints, some a combination.  Species IDs by K. Bernick (Bernick 1983). Age: ca. 1000 BP Burial Conditions:  See Stratigraphy description in Bernick 1983  (possibly A site catchment analysis of the Little Qualicum River site, DiSc 1, a wet site on the east coast of Vancouver Island, B.C.?)  Deterioration:	1972 treatments: look for records at RBCM- possibly not PEG treatments.PEG TREATMENT% MW: 50% PEG 1500  Duration: 2 months. Heated? No  Drying: Air Dried. (Simonsen 1976) (Note: PEG 1500 used in treatment may now be 540 Blend due to name change in mid 70’s)	2010: To date the authors have not examined the basketry material from this site.(Would be interesting to view since possibly two different treatments performed on materials).
Site: Montana Creek  (49-JUN-453)Date recovered/treatment: 1989-1991 Location of Collections: exhibit, Juneau-Douglas City MuseumMaterials: Hemlock and spruce wood with split basketry-like spruce root lashings Age: 400-600 BP  Burial Conditions: eroding river bank with high iron content sediment, small pebbles and sand (Loring, Jon 1995) Deterioration: Thought to have little deterioration	PEG TREATMENT% MW: 10% PEG 200, 5% PEG 1000 and 10% Carbowax Compound 20M (average mw 15,000-20,000) Duration: several months Heated? No  Drying: Air-Dried	2005: Tan color, not shiny or waxy, no observable distortion, rather brittle (Carrlee, 2005)2009: Artifact appears stable.
Site: Mud Bay (Qwu? Gwes) (45TN240)Date recovered/treatment: began 2000- ongoingLocation of Collections: Squaxin Island Tribe’s Museum Library and ResearchMaterials: western red cedar inner bark, maple inner bark, cedar with and root. Age: ~500  Burial Conditions: Deterioration:	PEG TREATMENT: LONG% MW: 50% PEG 400 Duration: 4 months. Heated? No  Drying: Air-dried (Standard treatment of lab at South Puget Sound Community College as described in Croes, Fagan, Zehender 2008)	2007, 2008, 2009:  Requests to examine collections and learn about the materials unanswered.
Site: Munk Creek (45SK156)Date recovered/treatment:  Location of Collections: Swinomish Indian Tribal CommunityMaterials: No reference found identifying material types or species Age: ca. 1000 AD (radiocarbon dated)  Burial Conditions:  found buried in riverbank/channel    Deterioration:	Not available at the time of publication.	2009: Request to examine collections denied at this time due to lack of protocol in collections policy.
Site: Musqueam East Site (DhRt 2) Date recovered/treatment: 1959;1974 / 1974-75 Location of Collections: LoA at UBCMaterials: No reference found identifying material types or species Age: Burial Conditions:  “blue Fraser River clay” (Bernick 1991) Deterioration:	1959 artifact air dried.1974-75 pieces treated with polyethylene glycol.PEG TREATMENT% MW: 50% PEG (MW of PEG unknown at this time) Duration: 4 months  Heated? No Drying:  Air dried (Bernick 1991)	1991: 1974 finds pliable, waxy and dark coloured; 1959 find encrusted with mud, brittle, broken, frayed (Bernick 1991)2010: To date the authors have not examined the basketry material from this site. Requests in 2008 and 2009 to the Musquem Band for permission to examine and possibly sample material from the collection were unanswered.
Site: Musqueam Northeast (DhRt 4) Date recovered/treatment: 1973 & 1974/1973-1975Location of Collections: LoA at UBCMaterials: western red cedar withe/root  (Archer and Bernick 1990)  Age: ca. 3000 BP Burial Conditions: Artifacts present in two superimposed matrices: lower layer— dense silty-sandy clay, upper stratum: dark, soft silty clay (Bernick 1991). Anaerobic.  Below the water table.  Capped by stratified shell midden and above that Fraser River alluvium.  Layers with basketry about 2 m below modern surface; likely deposited in a shallow/marshy creek originally. Deterioration:	PEG TREATMENT: MID-LONG% MW: immersed in 50% PEG 1500 Duration: 2.5-4 monthsHeated? No  Drying: Air dried (Note: the PEG 1500 may what we now consider 540 Blend due to name change in mid 70’s)	Staff anecdotal comments- weeping.1991“Most items are pliable and appear to be in relatively good condition…” (Bernick 1991)2010: To date the authors have not examined the basketry material from this site. Requests in 2008 and 2009 to the Musquem Band for permission to examine and possibly sample material from the collection were unanswered.
Site: Old Songhees Reserve (DcRu 25)  Date recovered/treatment: 1994Location of Collections:  RBCMMaterials: possibly yellow cedar inner bark,  western red cedar inner bark and spruce root Age: ~150 years old.  Burial conditions: Deterioration:	Currently undergoing treatment at CCI.	2010:
Site Pitt River Site (DhRq 21) Date recovered/treatment: 1980Location of Collections: RBCM Materials: western red cedar splints (Bernick 1981) Age: ca. 3000 BP  Burial Conditions: anaerobic alluvial deposits below the water table,; basketry was in unconsolidated silty clay, 1.2 m below modern surface, likely a slough when originally deposited.    Deterioration:	SOLVENTWoven artifact materials recovered were gently washed to removed soil and then slowly dehydrated ethanol and dried under restraint. (Bernick 1991)	1991: rigid and brittle (Bernick 1991)2010: To date the authors have not examined the basketry material from this site.
Site: Ozette (45 CA 24) Date recovered/treatment: 1970’s Location of Collections: Neah Bay, Makah Cultural and Research Center Materials: western red cedar inner bark, limb, root Age: 450 BP or younger    Burial Conditions: pH of 5.5-6 in 1970, water entering midden pH6 (Grosso 1976, vol 2, page 22) Deterioration:	PEG TREATMENT% MW: 50% Carbowax in water with anti fungal agent Cytox 2013 (Gleeson and Grosso 1976)Duration: 4 weeksHeated? No  Drying:  Air dried (Note: the PEG 1500 may what we now consider 540 Blend due to name change in mid 70’s)	1990: Artifacts dark brown to black with layer of excess PEG on surface.  Artifacts are stable. (Cooke and Cooke 1990)2009: While published reports and lab notes indicate that these pieces were all treated the same way the outcome is varied.  All of the materials are preserved.  However some are dry and medium brown in appearance, others dark brown, still others dark with a matte waxy surface, and a few with a wet shiny appearance.  While variation may be due to difference in material types it is interesting to note that hats containing both root and inner bark have same appearance.  Thicker splint pieces are lighter in color and drier in appearance.
Site: Scowlitz (DhR1-16W) Date recovered/treatment: 1992-1993/ 1993-1994 Location of Collections: temporarily at LoA at UBC Materials: western red cedar wood splints, IDs by K. Bernick (REF: Bernick 1994)  Age: ca. 1200 BP  Burial Conditions:  anaerobic alluvial desposits in riverbank, apparently originally deposited elsewhere and washed into that location in antiquity.  Specifically: in a 50-cm-thick layer of orange-mottled grey muddy sand pH=4.9, overlain by 20-cm-thick blue-grey sandy mud pH=3.5; and above that 15-cm-thick loosely packed sandy mudd pH 1.7.  Bottom of the sequence (under the matrix with the baskets) was angular rocks.  Completely inundated seasonally.    Deterioration:  “remarkably weak and in an advanced state of decomposition relative to similar material from other known sites in the region” when recovered, extensively infiltrated with rootlets (Bernick 1994)	PEG TREATMENTTwo treatment techniques used:% MW: Baskets A and B: immersed in 20% PEG 400 in water then 6 months in 20% PEG 400 and 4% PEG 4000 (3350 in US) in waterNumbered fragments: 4 months in 20% PEG 400 in water Heated? No  Drying: frozen, freeze-dried, then treated with Parylene to consolidate surface. (Conservation Treatment Records from CCI at LoA and Grant 1996)	2009: All materials appear fairly stable.  Materials have light brown, dry appearance. Very few loose bits exist in storage containers, possibly indicated stability.  Elements appear to have minor flexibility.
Site: Seymour Inlet ( ) Date recovered/treatment: Location of Collections: RBCMMaterials: wood splint baskets Age: est.100-200 years old.  Burial conditions: Deterioration: materials damp not waterlogged when found. (Bernick 2010)	Air Dried.	2010:
Site: South Baranof Island (49-XPA-78)Date recovered/treatment: 1995 Location of Collections: Alaska State MuseumMaterials:  possibly hemlock or spruce by ML Florian; Age: 4510 +/; 60 uncal BP  (cal 3350-3100 BC)  Burial Conditions: water-saturated dark brown clayey silt, intertidal stream bank; original depositional topography uncertain, likely affected by tectonic uplift  Deterioration: Moderate to very deteriorated?	PEG TREATMENT% MW: 20% PEG 400 and 5% PEG 4000 Duration: 6 monthsHeated? no  Drying: Non-vacuum freezer (ASM treatment records)	2009: Surface is dry, brown.  Flexible, almost spongy softness.  Texture of fibers evident on surface.  Too delicate for exhibition or travel.
Site: Sunken Village (35 MU 4) Date recovered/treatment: 2006/07 Location of Collections: University of Oregon Oregon State Museum ?Materials: cherry bark, western red cedar Age: 500-700 years old (1400-1450 AD)  Burial Conditions: in anaerobic alluvium on river bank (tidal) Deterioration:	PEG TREATMENT% MW: 50% PEG 400 Duration: at least four months of impregnationHeated? No  Drying:  Air Dried (Croes, Fagan, Zehender 2008)	2010: To date the authors have not examined the basketry material from this site.  Collection materials moved to Oregon State Museum at University of Oregon in Fall 2009.
Site: Tawah Creek (49-YAK-019)Date recovered/treatment: 2004 Location of Collections: Alaska State MuseumMaterials: possibly spruce root Age: possibly 130 years old (weir at site was dated) Burial Conditions: Deterioration: Moderate deterioration?	PEG TREATMENT% MW: 50% PEG 540 Duration: over 1 month Heated? 60 degree C oven  Drying: non-vacuum freezer.  (ASM treatment records)	2009: Appears stable, edges need consolidation from physical unraveling because basket has stress from its three- dimensional shape.  Has been stored in stable environment for past two years.
Site: Thorne River  (49-CRG-433)Date recovered/treatment: 1994 Location of Collections: Alaska State MuseumMaterials: root (spruce—possibly hemlock?) Age: 3450 BCE, (5450 years old carbon 14 dating +/-) Burial Conditions: Deterioration: Moderate to very deteriorated?	PEG TREATMENT% MW: 20% PEG 400 and 5% PEG 4000 Duration: 6 months Heated? No  Drying: non-vacuum freezer. (ASM treatment records)	2009: Basket is mostly in one large piece and is stabilized from deterioration.  Appearance is good, but it is too fragile for exhibit or travel. Dry, flexible, spongy.
Site: Wapato Creek (45 PI 47)Date recovered/treatment:Location of Collections: Burke Museum, Materials: western red cedar inner bark  Age: 340  Burial Conditions: in 2-m-deep anaerobic alluvial deposits that were covered by 2+ m of industrial fill (Munsell 1976)   Deterioration:	PEG TREATMENTPlaced in Ethanol for two days (to reduce trapped H2O between fibers and facilitate PEG exchange) % MW: 50% PEG 1000 Duration: 2-4 days  Heated? No  Drying: dry on racks (1-2 weeks)  (Munsell 1976)	2006: hat appeared dry and brittle but stable. 2010: Piece has safely traveled for exhibit for two years.
Site: Water Hazard (DgRs 30)Date recovered/treatment: 1988/1989 treatment Location of Collections: LoA at UBCMaterials: western red cedar wood splints and inner bark.  One may have yew components and another hemlock. (by Jack Gray in Bernick 1989) Age: 1700 BP  Burial Conditions: below watertable in anaerobic Fraser delta sediments; about 2 m below present surface; likely originally desposited in a slough or salt marsh (recovered from backhoe spoil piles ergo matrix it was in uncertain but appears to have been near interface of sandy matrix with pH 6.8 and “blue-grey silty clay” pH 6.2—Bernick 1989:30).   Deterioration:	PEG TREATMENT% MW: PEG 540 Blend, concentration unknown.  Duration: 4 weeks Heated? No  Drying: Freeze dried (Erling 1989)	2009: Artifacts appear stable.  No evidence of weeping.  Also appear to have some flexibility—but not much.  Splin fragments more flexible than inner bark.
Site: Yakutat  Date recovered/treatment: Location of Collections:  possibly at Forest Service Office, SitkaMaterials: Age:   Burial conditions: Deterioration:	Treated with Silicon Oil treatment at Texas A&M	2010:

 

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[1] Royal British Columbia Museum

[2] Laboratory of Archaeology of University of British Columbia

[3] Thomas Burke Memorial Washington State Museum

High Molecular Weight PEG for Basketry

 

Introduction: PEG treatments for waterlogged archaeological basketry at the Alaska State Museum and published treatments for such basketry suggest that use of mostly low molecular weight PEG was not enough to impart the stability needed for study and exhibition.  This experiment investigated the use of various concentrations of high molecular weight PEG.  Testing included impregnation in both room-temperature solutions and solutions kept in a 60degree F oven.  Informed by these results, the Alaska State Musuem decided to proceed with treatment using 55% PEG 3350.

Catalog No:  95-12-6

Object: Basketry fragments

Culture:  Northwest Coast Native, possibly Tlingit.

 Description:  Sixteen samples from 95-12-6, a large group of approximately 300 fragments (mostly knots.)  Artifact described by archaeologists as spruce root webbing or semi-rigid netting.  Reconstruction of this artifact is unlikely, and the large number of similar small fragments give good comparative study samples.  Material is most likely spruce root.

 

 

 

 

 

 

 

 

 

 

 

 

ASM 95-12-6 semi-rigid knotted netting

 

 

 

 

 

 

 

 

Condition:  All fragments stored in distilled water in a refrigerator since their discovery in 1995. Biological growth has occurred in the past. Water was rarely changed. Since 2006, little biological growth has been noted. All fragments are fragile.

Background/ Reason for Report:  Found on South Baranof Island in 1995.  Another basket from this site, 95-12-1, was already treated.  It was C-14 dated at 4,450 years BP and the material was (with some controversy) identified as hemlock and not spruce root.  20% PEG 400 and 5% PEG 4000 was the protocol used by the ASM to treat 95-12-1 as well as the ancient Thorne River spruce root basket from a different site.  The physical appearance of both those treated baskets is pleasing, but they are still too fragile to be exhibited or handled easily.  They are very flexible and shed fibers readily.  Perhaps the PEG concentrations were too conservative?  This experiment intends to test the theory that an increased amount of higher molecular weight PEG might yield better results.

PROPERTIES OF PEG

Low molecular weight PEG (PEG 200-600) is thought to penetrate more deeply into the secondary cell wall and the smaller spaces in the wood than higher molecular weight PEG.  It is also more mobile and hygroscopic.  If too much is used, the surface will look wet, feel soft, attract dust, and be humidity-sensitive.  High molecular weight PEG (PEG 1500-6000) does not penetrate the secondary cell wall because the molecule is too large, but it acts like a filler, impregnating the lumens and interstices between the cells.  Addition of higher molecular weight PEG is thought to be helpful if the wood is more degraded.  Too much high molecular weight PEG can leave white crusts on the surface, result in a heavy artifact, and be harder to dry.  A combination of high and low molecular weights of PEG is often the solution, but it can be tricky to determine the right mixture for solid wood, and basketry is even more challenging.  Higher molecular weight PEG is thought to cause damage if used on wood with fairly intact cell wall structure, perhaps from the force as the hygroscopic PEG pulls water out of the smaller structures where the PEG molecule cannot penetrate? (Astrup 1994, Grattan 1996.)

Low mw PEG is a liquid, and high mw PEG is a solid powder

 

 

 

 

 

 

 

 

 

HEATING

PEG 540 blend was used in the ASM lab on the Tawah Creek basket at 50% concentration for a month at 60°C in the lab oven with good results.  Heating may speed and enhance penetration as well as the solubility of high molecular weight PEG (Grattan and Clark 1987.)  However, heating was thought to contribute to undesirable darkening for the objects treated at the Ozette site (Cooke, Cooke and Grattan 1993.)  Heat is an accelerant to deterioration and PEG treatments for leather in the literature have mostly eliminated heat altogether for that reason.  Heat is also thought to break down the PEG molecule, and some sources have suggested not heating PEG during the impregnation (Bilz et al 1994.)  Since most of our fragments are small enough to put in the oven, it would be worth knowing if heating provides an advantage. 

Goals of Treatment:  The treatment for these 16 fragments will give data that will set the protocol for stabilization treatment of the other waterlogged basketry fragments in group 95-12.  Several variables affect PEG treatment: deterioration of the wood, species of wood, anatomical structure of the wood (bark, trunk, root etc,) concentration of PEG used, molecular weight of PEG used, duration of soaking, and heating during impregnation.  The proposal aims to address the following questions:

1. Can we develop a PEG protocol that will make the waterlogged artifacts stable enough for study and exhibition?
2. What are the optimum concentrations of PEG for this basketry?
3. What are the optimum molecular weights of PEG for this basketry?
4. Will increasing the amount of high molecular weight PEG specifically help?
5. Does heating during treatment provide a benefit?
6. Will the treated artifact be vulnerable to high humidity?

Stabilization will prevent ongoing deterioration and allow future study and exhibit as part of the permanent collection.  After treatment, additional research into adhesives for mending broken fragments may be undertaken.  The results of the PEG basketry treatments here over the past 15 years would be of interest to the conservation field and should probably be published.  There is very little in the conservation literature about successful treatment of waterlogged basketry.  Additional consolidation of the two ancient baskets already treated in the collection is needed for added stability, which might be achievable with nebulizer mist application.  Adhesives and consolidants will be explored in separate future treatment proposals.

Sample knot, waterlogged, before treatment

 

 

 

 

 

 

 

 

 Treatment Methodology and Rationale:  Samples fell into three main groups.  Each group had five fragments treated with various concentrations and molecular weights:

1. Samples treated at room temperature

2. Samples treated at 60°C

3. Samples treated briefly at 160°C and then at 60°C.  (This grouping was the result of an error that led the samples to be overheated for approximately 12 hours.)

20% PEG 400, then 20% PEG 3350

Rationale: PEG 400 will enter the secondary cell wall and bond there, while the 3350 will fill in the larger voids and give strength.  This is slightly higher than the concentration of 3350 PEG used previously in the lab, but those examples did not give enough strength. PEG 400 is kept at 20% to hopefully prevent excess from oozing out.

20% PEG 400, then 35% PEG 3350

Rationale: High molecular weight PEG is supposed to perform well on highly degraded wood.  Our basketry is very old and treatment with mostly low molecular weight PEG was not fully successful.  This suggests the basketry may be more degraded than predicted, and may respond better to high molecular weight PEG.

20% PEG 400, then 55% PEG 3350

Rationale: Some references suggest avoiding the eutectic, but others (Jensen et al 2000) seem to suggest that aiming for the eutectic is desirable.  Theoretically, ice crystals form in a way that blocks even distribution of the PEG unless the eutectic is used.  Apparently, concentrations lower than the eutectic also expand on freezing, causing cracks.  At the eutectic, the 9% expansion of ice is counterbalanced by 7% volumetric contraction of PEG.  A medieval log house in Oslo was treated successfully with 50-55% PEG 4000 (Astrup 1994.)  The successful Tawah Creek basket treatment by Scott Carrlee (unpublished, Alaska State Museum) used PEG 540 near the eutectic.

55% PEG 3350 alone 

Rationale: Since the Jensen et al article (2000) seems to suggest PEG near the eutectic is optimal even though other articles specifically indicate the opposite, it would be worthwhile to isolate the PEG 3350 to test this.  Perhaps it simplifies the phase diagram to only use one molecular weight of PEG.  Astrup (1994) and Hoffman (1990) found some success with 50% PEG 4000 in degraded softwoods.

20% PEG 400, then 75% PEG 3500 

Rationale: Several sources report success with high concentrations of high molecular weight PEG for highly degraded wood (DeWitte et al 1984, Kaenel 1994.)

 

 

 

 

 

 

 

 

Fragments of similar size with no obvious joins to other fragments were selected for testing and photographed.  Each sample was sewn between layers of nylon mesh screening with polyester thread to hold the fragment securely, allow good circulation around the fragment, and permit handling.  Each PEG concentration was increased incrementally approximately every two weeks.  PEG 400 was increased in 5% increments, PEG 3350 was increased either 5 or 10% increments.  In each case, the concentrations were increased gradually to minimize the risk of osmotic shock from pressure differentials between the fluid inside the fragile wood and the fluid in the container.  The time to reach desired concentration took between 3 and 6 months.  PEG 3350 was supplied as a powder and was dissolved in a bit of the test solution using a hotplate before adding it to the unheated and heated sample containers.  For the unheated samples, the addition of the warm PEG 3350 caused them to be cloudy for two to three minutes before becoming clear again.  All samples were removed from solution at the same time.  Each sample was rinsed in a beaker of distilled water to rinse excess PEG from the surface and gently tamped with KimWipes to remove as much water as possible before freezing.  Fragments were weighed and placed in the freezer (-35°C) to drive off the excess water through sublimation (solid ice directly to water vapor.)  Air drying without the freezer would send liquid water to water vapor, and the strong surface tension of the liquid water contributes to collapse of cell structure as the water evaporates.  Samples were regularly weighed to determine the end point of drying (when weight no longer decreased,) and fragments were all removed at the same time.  After removal from the freezer, fragments were taken out of the nylon mesh and photographed on graph paper while still cold.  They were photographed on graph paper again a week later to check for possible distortion from the evaporation of residual water at room temperature (none observed.)  A month after they were removed from the freezer, they were subjected to 80% humidity for 12 hours. 

 

 

 

 

 

 

 

 

Front and back of fragment cold out of freezer, and here fully dry

 

 

 

 

 

 

 

 

 

Results and Interpretation: While waterlogged, the wood was dark brown in color.  After treatment, the room temperature samples all turned out very pale beige-gray driftwood-like color, with no obvious color difference with higher concentrations.  60°C oven samples were all pale yellow ochre-grayish in color, but still much paler than most historical basketry.  160°C overheated samples were a rich brown burnt umber color, ironically more like historical spruce root basketry in color, and the higher concentrations were darker.  The untreated air-dried control sample was the darkest of all (dark burnt umber) and extremely brittle, shrunken, and deformed.  Almost all samples had some whitish powdery PEG residue/crusts in the crevices, and this did not seem to increase with concentration, but it was more pronounced on the samples impregnated at room temperature.  The waxy PEG could not easily be brushed from the surface (the brush tended to drag it around) but localized application of ethanol with a brush under magnification seemed to drive the PEG below the surface and improved the appearance.  All impregnated samples were placed in the humidity chamber and raised to 80% RH for 12 hours to evaluate effect of high RH on the concentrations and molecular weights of PEG used.  No oozing or surface changes were observed on the samples or on the blotter paper below them.  While the Alaska State Museum has stable RH, there are less stable locations in Alaska that may wish to exhibit the artifacts after treatment.

 

UPDATE: From a suggestion by Dana Senge, I repeated the RH test.  The 75% concentrations of the unheated and the overheated samples both oozed, and their surfaces got very dark and waxy.  This did not revert back upon stabilization of the RH, and did not seem to get worse with repeated RH tests.  The heated 75% sample did not ooze or get dark, even on repeated RH fluctuations.

 

Humdity test at 80% RH

 

 

 

 

 

 

 

 

20% PEG 400, 20% PEG 3350

Room Temperature: Weight loss stabilized after 20 days in the freezer, sample lost 22% of its wet weight

Heated: 65 days, lost 22%

Overheated: 40 days, lost 33%

20% PEG 400, 35% PEG 3350

Room Temperature: 40 days, lost 23%

Heated: 90 days, lost 21% 

Overheated: 40 days, lost 25% 

20% PEG 400, 55% PEG 3350

Room Temperature: 65 days, lost 23%

Heated: 90 days, lost 23%

Overheated: 20 days, lost 22% 

55% PEG 3350 

Room Temperature: 90 days, lost 23%

Heated: 65 days, lost 18% 

Overheated: 20 days, lost 22% 

20% PEG 400, 75% PEG 3350 

Room Temperature: 90 days, lost 20% 

Heated: 20 days, lost 10% 

Overheated: 65 days, lost 18% 

Samples after treatment: unheated rather gray, overheated brown, heated yellowish. Control in upper corner

 

 

 

 

 

 

 

 

 

Assumptions: a lower percent weight loss during drying means less water was lost and there was less water to lose in the first place because it had been replaced by PEG.  If this is true, all the room temperature fragments had about the same amount of water loss, and therefore a similar amount of PEG penetration.  But at higher concentrations, the heated fragments had less water loss, and thus better penetration of PEG 3350 than the room temperature samples.   Explanations could include better penetration of molecules that may have some size variation through thermal breakdown, better diffusion, possible expansion of wood structure with heat to allow better penetration, or the enhanced solubility of heated PEG (Grattan and Clark 1987.)

The samples with lowest concentrations were distinctly spongier to the touch than those with 55% 3350 and higher, in spite of similar amounts of weight loss.  Surprisingly, results for 20% PEG 400 with 55% PEG 3350 were the same as the results for 55 % 3350 alone. 

Flaws: I may be misinterpreting the Jessup et al (2000) article about the eutectic.  Varying geometry of the shape of the knots made my qualitative comparisons about flexibility and brittleness too subjective.  Sample size was not statistically significant.  Have not done cobalt thiocyanate staining to see which samples have more PEG in them under microscopic examination.   Determining degree of deterioration from the molecular weight of PEG that works is a backwards method.  I began an experiment in July 2009 to try to determine the moisture content of the archaeological basketry compared to historical basketry samples waterlogged artificially in the lab.  Also need to spend some time examining the samples structurally under the microscope.

Conclusions:  The idea that high molecular weight PEG around 55% concentration is useful for highly degraded softwoods is in harmony with the conclusions found by others (Astrup 1994 and Hoffmann 1990.)  The superior performance of the heated 75% solution was based on a single fragment losing a total of only 0.1g of water in the freezer after only 20 days.  Could this be an anomaly?  If 55% PEG 3350 does not give adequate stability for the first basket I treat, I may attempt the higher concentration.  The oozing of the 75% fragments at room temp and with voerheating makes me nervous.

Annotated Bibliography:

Astrup, E.E. “A Medieval Log House in Oslo – Conservation of Waterlogged Softwoods with Polyethylene Glycol.”  Proceedings of the 5^th ICOM Group on Wet Organic Archaeological Materials Conference, Portland, Maine. 16- 2- August 1993.  Pub 1994 pp 41-50

Ellen Carrlee’s Notes: Wood was identified as pine (Pinus silvestris) and spruce (Picea abies).  For both highly degraded and less degraded softwoods, 50-55% PEG 4000 was most useful.  She heated at 60°C adding 10% every 8 weeks.  She was getting 3-5 % shrinkage in the 50-55% range, but more above and below it.  Waterlogged wood is already somewhat swollen, however.  Results similar to Hoffmann’s 1990 article on softwoods.  Wood with fairly intact cell wall structure might suffer from shrinkage with low mw PEG alone, perhaps the hygroscopic PEG pulls the water out of tyhe small spaces the molecule cannot fir into?  Mentions that the two-step method is really intended for wood like oak that tends to have areas of both low and high degredation.

Barbour, R.J. and L. Leney.  “Shrinkage and Collapse in Waterlogged Archaeological Wood: Contribution III Hoko River Series.  In book. Proceedings of the ICOM Waterlogged Wood Working Group conference: Ottawa, 15-18 September 1981. ICOM Waterlogged Wood Working Group (1982), pp. 209-225.

Ellen Carrlee’s notes: Shrinkage from capillary tension happens when the free water is pulled by evaporation from the void structure of the wood.  Shrinkage is also caused from desorption of bound water from the cell wall.  Article gives extensive info about which cells collapse in which direction.

Bilz, Malcolm, Lesley Dean, David W. Grattan, J. Clifford McCawley, and Leslie McMillen.  “A Study of the Thermal Breakdown of Polyethylene Glycol.”  Proceedings of the 5^th ICOM Group on Wet Organic Archaeological Materials Conference.  Portland, Maine. 1993.  Ed Per Hoffmann.  1994.

Ellen Carrlee’s Notes: PEG from ten year old artifact did not decrease in molecular weight.  Keeping oxygen or air out slows PEG degradation.  Thermal aging increases PEG degradation.  Slightly more degradation of PEG 3350 in presence of iron salts, but not so much with PEG 200.  Less degradation of PEG 3350 in oak than by itself.  BHA (not very soluble in water) helps reduce oxidation degradation of PEG 3350; propyl gallate does not, and also forms colored complexes with iron.  No degradation of PEG with natural aging either in artifacts or by itself.  Impregnation should take place at room temperature to avoid degradation.  Store PEG at its most concentrated.  PEG is reasonably reversible and can be leached from artifacts.  Lower concentrations of PEG 400 (below 40%) oxidize more.  In degradation, are we getting smaller molecules, do they go into the wood, or do they evaporate? 

Cooke, Vincent, Deborah Cooke, and David W. Grattan.  “Reversing Old PEG Treatments of Objects from the Ozette Site.”  Proceedings from the 5^th ICOM Group on Wet Organic Archaeological Materials Conference, Portland, Maine 16-20 August. 1993. 1994. pg 92-109

Ellen Carrlee’s notes: Treated with PEG 540 blend c. 1973, hygroscopic, dark, heat used.  Extracted PEG, retreated with 2-step PEG 200 at 15% for 40 days, and PEG 3350 at 9.5% for 20 days, then freeze dried.  Acetone Rosin was found irreversible.  They also consolidated with Polyox 2.5%.

Cook, Clifford and David Grattan.  “A Method of Calculating the Concentration of PEG for waterlogged Wood.”  Proceedings of the 4^th ICOM Group on Wet Organic Archaeological Materials.  Bremerhaven 1990.

Ellen Carrlee’s notes: Liquid grade, such as PEG 200 is used to control cell wall shrinkage and waxy solid PEG 3350 is used to give some structural strength to the wood.  Important to know:

1. Wood species
2. Actual density of the wood
3. The normal density of undeteriorated wood
4. The Moisture content at the fiber saturation point of the undeteriorated wood.

These are the parameters used by PEGCON.  Lower MW PEG such as PEG 200-600 penetrate into the cell wall better than higher MW.  Higher MW PEG is meant to fill in the lumens and has been shown to work better on very deteriorated wood.  Too much PEG 400 results in weeping , soft, humidity-sensitive wood.

Too much PEG 3350 results in heavy wood, harder to dry. Umax is the maximum moisture content, increases with deterioration.  Some woods have a higher Umax naturally than others, so that’s why you have to know the species.  Over 55% PEG mixture might not freeze in the drying process.

Christensen, B. Brorson.  The Conservation of Waterlogged Wood in the National Museum of Denmark.  National Museum of Denmark, Copenhagen, 1970. 

Ellen Carrlee’s notes: Includes history of treatments 1859-1962, and reports on work thusfar on Viking ships from Roskilde Fjord.   Includes PEG 4000 in various solvents but having difficulty with the issue of oak penetration.  Methylene chloride is the best solvent for removing PEG after treatment.  Water is too slow and results in too much rubbing which obscures fine details and rounds sharp edges.  Cold treatment with PEG 4000 as opposed to warm treatment resulted in less collapse of the oak.  Began with 25% and increased to 50% for a year total

DeWitte, Eddy, Alfred Terfve, Jozef Vynckier.  “The Consolidation of the Waterlogged Wood from the Gallo-Roman Boats of Pommeroeul.”  Studies in Conservation Vol 20 no 2 1984.  pp 77-83

Ellen Carrlee’s notes: PEG impregnation with PEG 4000 up to 85% heated to 65C in a steel tank.  Oak with no solid core.

Florian, Mary-Lou and Richard Renshaw-Beauchamp.  “Anomalous Wood Structure: A Reason for Failure of PEG in Freeze-Drying Treatments of Some Waterlogged Wood from the Ozette Site.”  Proceedings of the ICOM Waterlogged Wood Working Group Conference Ottawa 1981. pub 1982 pp. 85-98 

Ellen Carrlee’s notes: Factors that decrease the penetration of the PEG include:

• Few and small hardwood cells
• Inclusions (gum and tyloses) in hardwood vessels
• Abundant hardwood thick walled fiber cells
• Short soft wood longitudinal tracheids
• Absence of ray tracheids
• Absence of radial and longitudinal resin canals
• Aspirated and encrusted bordered pits
• Blind simple pits
• High specific gravity
• Ray parenchyma containing resin or extraneous material
• Reduced tangential wall pitting
• Extractives in heartwood

Picea sp. (spruces) and Thuja pliacata (Western red cedar) have no tangential permeability due to little tangential wall pitting, blind pits, and resin in the ray parenchyma cells.  Spruce more permeable than red cedar due to resin canals and ray tracheids.  Cedar is vulnerable to collapse of radial walls of the tracheids.  In some woods, large thin-walled early wood tracheids adjacent to thick walled later wood tracheids can collapse and cause uneven grain appearance.  In this case, spruce showed this result.  Roots have many parenchyma cells and can have excessive longitudinal shrinkage.  List of history-chemical tests given.  Many softwoods samples show open enlarged tracheid bordered pits which make the wood abnormally porous. 

Grant, Tara and Malcolm Bilz.  “Conservation of Waterlogged Cedar Basketry and Cordage.”  Proceedings of the 6^th ICOM Group on Wet Organic Archaeological Materials York, 1996.

Ellen Carrlee’s notes: Parylene coating on cedar “bark” baskets from Scowlitz site (500-1200 years old)  treated with modified PEG treatment. 20% PEG 400 for 3 months and then freeze-dried.  Came out still too fragile.  Parylene is irreversible but worked well.  Need a special vacuum pyrolysis chamber to apply it.  NOTE: Bilz reported at the 11^th ICOM-CC Triennial in Edinburgh Sept. 1996  that further study of Parylene shows that it does not age as well as they thought and it is not recommended for long term conservation.  Also, personal communication with Kathryn Bernick (April 9, 2009) she mentions that the Scowlitz baskets are all made of cedar withes (wood splints) and not bark.  Some of the cordage was indeed bark.

Grattan, D.W. and R.W. Clarke.  “Conservation of Waterlogged Wood.”  In, Conservation of Marine Archaeological Objects. Ed Colin Pearson.  Butterworth. London and Boston. 1987. 164-206   

Ellen Carrlee’s Notes: This is really the most comprehensive description of PEG use and especially its history, but of course it ends in 1987 AND this book is out of print and can be hard to come by.

  If PEG 3350 is too bulky to penetrate the cell wall, osmotic pressure could build and cause collapse.  Microcapillaries in the cell wall thought to be around 10nm in deteriorated wood. Idea that bulking the cell wall without bulking the lumina has better results: less PEG oozes out, more natural appearance.  Freeze drying gives a more even distribution of PEG.  Grades of PEG over 600 need to be warmed in order to be completely dissolved, and the complete solubility of PEG in water is very important.  Beginning impregnation with a low percentage of PEG is important to prevent osmotic collapse.  Up to 30% PEG 400 is needed to bulk the cell wall.  Freeze drying helps to keep it in there.  Very deteriorated wood doesn’t have much cell wall and so the low mw PEG can’t stay in there as well.  At the eutectic, PEG can’t freeze so you have a drying from with solid on one side and a mushy PEG solution on the other side. 

Grattan, David W.  “International Comparative Study; Report”  .  ICOM Committee For Conservation Working Group on Wet Organic Archaeological Materials Newsletter. no 14. Feb 1986. 

Ellen Carrlee’s Notes:  I don’t remember seeing this published as a final thing elsewhere?  Grattan described his work at CCI.  He treated some samples with equal parts PEG 400 and PEG 3350 raised in 10% increments up to 30% v/v.  Frozen at -40C and then freeze dried at -20C.  results were good, but the very deteriorated samples should have had less 400 more 3350.   Second batch placed in PEG 3350 in sequential batches of 10%, 20%, 30%m 40%, and 50% v/v and then freeze dried.  Grattan feels the PEG reach the eutectic and did not freeze, so unfrozen PEG exuded onto the surfaces during freeze drying and some surface collapse.

Grattan, David W.   “Some Observations on the Conservation of Waterlogged Wooden Shipwrecks.”  AICCM  Vol. 12 No 3 and 4. 1986.

Ellen Carrlee’s Notes: Diagram of meniscus for water in a capillary, discussion of capillary tension induced collapse.  Issue of PEG penetration into white oak timbers.  Air pockets might prevent penetration.  For more deteriorated wood, concentrations over 50% are better, and fill the lumens in addition to bulking the cell wall.  Less deteriorated wood does all right with 10-30% which only bulks the cell wall.  Capillary action during drying concentrates PEG at the surface and depletes the core…this can be overcome using concentration over 50%. (ellen: also, if you freeze, doesn’t ice crystal formation influence where the PEG ends up?)  For humidity about 80% all PEGs are affected.  Lower concentrations of PEG can be used with freeze drying than with air drying.

Grattan, David W.  “A Practical Comparative Study of Several Treatments for Waterlogged Wood”  Studies in Conservation Vol 27 No 3 Aug 1982 pp 124-136

Ellen Carrlee’s notes: Water content is a rough guide to the state of deterioration.  For smaller sample, no advantage to heating the PEG 400.  Didn’t help with penetration, shrinkage or cracking, but it did make end result darker.  In larger objects, heat may speed up the diffusion.  PEG 400 can end up soapy and attract dust.  Can melt some PEG 4000 on surface to make it stronger and less absorbent.  PEG 540 is a 50/50 blend of 300 and 1540 MW ave of 500-600…tends to creep out of the wood, looks heavy, dark, waxy.  Can be introduced unheated and unstirred in 10% increments over 18months.  Final concentration 64% v/v. 

Grattan, David.  “A Practical Comparative Study of Treatments for Waterlogged Wood part II The Effect of Humidity on Waterlogged Wood.”  Proceedings of the ICOM Waterlogged Wood Working Group Conference Ottawa 1981. pub 1982 pp. 243-252.

Ellen Carrlee’s notes: Wood treated with low MW PEG (400 or 540 blend) should not be exposed to RH above 60%.  Below that shouldn’t matter.  Union Carbide PEG 4000 has been renamed PEG 3350.

Hamilton, Donny L. Methods of Conserving Archaeological Material from Underwater Sites.  Nautical Archaeology Program Department of Anthropology Texas A&M University.  1998.

Ellen Carrlee’s notes: Amount of water in waterlogged wood is calculated: weight of wet wood minus weight of oven dried wood divided by weight of the oven dried wood and multiplied by 100 to give % water.  Anything over 200% is considered degraded.  Explanations of other treatments for waterlogged wood are also given.

Hoffmann, Per, Adya Singh, Yoon Soo Kim, Seung Gon Wi, Ik-Joo Kim, Uwe Schmitt.  “The Bremen Cog of 1380: An Electron Microscopic Study of it Degraded Wood Before and After Stabilization.”  In Holzforschung Vol 58 No 3 2004 pp 211-218

Ellen Carrlee’s notes: Two-step PEG treatment for wood degraded primarily by erosion bacteria.  SEM/TEM investigation.  In degraded tissues, all cell types were filled with PEG 3000.   Non-degraded tissues are impermeable to PEG 3000 and impregnated only with PEG 200.  Confirms that PEG 200 goes into the cell walls.

Hoffman, Per.  “On the Stabilization of Waterlogged Softwoods with Polyethylene Glycol (PEG).  Four species from China and Korea.”  Holzforschung. Vol. 44 No 2.  1990.  pp 87-93.

Ellen Carrlee’s notes: Best stabilization of degraded softwoods is 50% PEG 4000 with cross section shrinkage of only 2-4%. 

Hoffmann, Per.  “On the Stabilization of Waterlogged Oakwood with PEG II Designing a Two-Step Treatment for Multi-Quality Timbers.”  Studies in Conservation 31 (1986) pp.103-113

Ellen Carrlee’s notes: Bremen Cog PEG 200 and then PEG 3000.  Two step for thicker woods with outer layer of degraded wood and a core of less degraded wood like oak and pine.  Can even do simple air drying afterwards.  Results with intermediate MW not as good as two step.  PEG 200 stabilizes slightly degraded wood better than PEG 300.  Maybe some lower MW PEG diffuses out during the second step, but some is trapped or adsorbed in the capillaries.  Doesn’t weep until RH is 86%.  Can be air dried, too big for a freeze dryer.

Hoffmann, Per. “On the Stabilization of Waterlogged Oak with PEG – Molecular Size Versus Degree of Degradation.”  Waterlogged Wood Study and Conservation, Proceedings of the 2^nd ICOM Waterlogged Wood Working Group Conference, Grenoble, France.  1984.  pp. 243-252.

Ellen Carrlee’s notes:  More degraded oak does better with PEG 3350, while less degraded does better with PEG 200.  PEG 1450 is poorer for both.  A 2-step method is more effective.  For a long time people were afraid to use anything under PEG 1500 for fear it would be too hygroscopic.

Jakes, K.A. and L.R. Sibley.  “Survival of Cellulosic Fibres in the Archaeological Context.” In Science and Archaeology. No. 25, pg 31-38. 1983.* Jeberien, Alexandra and Malcolm Bilz.  “Comparison of Air Dried and Freeze Dried Solutions of Polyethylene Glycol 3350”  In ICOM WOAM Newsletter No. 31 June 2000.

Ellen Carrlee’s notes: They expected all to line the walls and bottom of beakers.  Air dried samples had consistency of beeswax and occupied only the bottom the beaker, might have lined walls if they were more porous?  Freeze dried samples had a powdery matrix appearance and occupied the full volume that the frozen water/PEG mix had originally occupied.  For the freeze-dried, when they were returned to low temperature, higher concentrations that had been freeze-dried (20% and above) showed some concentrated PEG solution at the bottom of the beaker that had not been able to get past plugs of PEG.  5% did not have that, so water must have escaped.  

Jensen, Poul; Grethe Jorgensen, Ulrich Schnell.  “Dynamic LV-SEM Analyses of Freeze Drying Processes for Waterlogged Wood”  Proceedings of the 8th ICOM Group on Wet Organic Archaeological Materials Conference, Stockholm, 11-15 June 2001 Pub.  2002 pp.319-333

Ellen Carrlee’s Notes: Looking at distribution of PEG in wood with Low Vacuum Scanning Electron Microscopy (can avoid sputter-coating of SEM and the bias it introduces.)  Machine itself acts like a freeze-dryer with wet samples.  Phase diagrams for PEG done by different authors usually don’t agree, but they all agree the eutectic is around 55% (w/w) for all the mw of PEG.  Eutectic temperatures are not in agreement.  Below the eutectic temperature, a solid lamellar eutectic phase forms between the ice crystals.  Phase diagram they suggest for PEG 6000 shows solid PEG as well as a solid PEG/ice mixture at freezing temperatures with a concentration above 55% (eutectic.)  Below the eutectic, all PEG solutions result in 3-9% expansion at temps below freezing.  Ice has 9% expansion, PEG has 7% volumetric contraction.  Is this a primary function of the PEG?  PEG solutions below 55% all expand on solidifying.  PEG concentrated in the later wood and distributed irregularly in the early wood.  Collapse can be avoided if we stay below the eutectic temperature.  When ice forms, the PEG gets more concentrated.  Formation of large ice crystals contributes to uneven distribution of PEG.  Even distribution of PEG is only possible for eutectic concentrations.  PEG has a low affinity for the secondary cell wall (Jensen’s PhD thesis from 1995.)  Heating after freeze drying causes the PEG to aggregate on surfaces of cell wall and give better distribution.  They suggest investigating methods to nucleate smaller ice crystals and thus better distribution.

Kaenel, Gilbert.  “PEG Conservation of a Gallo-Roman Barge from Yverdon-les-Baines (Canton of  Vaud, Switzerland.)”  Proceedings of the Fifth ICOM Waterlogged Archaeological Materials Conference.  Portland, Maine 16-20 August 1993.  Pub 1994.  pp. 143-165.

Ellen Carrlee’s notes: Mostly oak, treated in a tank with PEG 4000 raised from 15% to 85% at 60C over 18months of impregnation.  AD 400.  Slow drying, natural looking finish reported.

Keene, Suzanne.  “Waterlogged Wood from the City of London.”  Proceedings of the ICOM Waterlogged Wood Working Group Conference Ottawa 1981. pub 1982 pp. 177-180

Ellen Carrlee’s notes: Variety of different hardwoods and softwoods.  PEG 4000 was used up to 90% at 50-60C, but wood came out dry and splintery so they switched to PEG 1500.  Rinsed with hot water, wrapped in towels and dried slowly in the dark.  Objects come out heavy, brittle, but not much shrinkage.  A little darker, and fine detail is preserved.  For freeze drying, PEG 400 left the wood too fragile, 40-50% PEG 1500 or 4000 worked better.  She’s down on acetone/rosin because while other colleagues have had luck with metal handled tools, she’s not had the best luck and working with hot acetone is difficult.

Lindblad, Cecilia and Ingmar Persson. “Polyethylene Glycol/ Polyethylene Oxide: An Overview of the Physical-Chemical properties of PEG/PEO”  Presented at the ICOM-CC Working Group on Wet Organic Archaeological Materials in Amsterdam, 2007.  Not yet published.

Ellen Carrlee’s notes:  Persson generously sent me a copy.  Describes a lot of chemistry of the polymer.  There’s no clear distinction between PEG/PEO.  PEG extremely soluble in water, but solubility of PEO actually decreases with high temps, salt, and strong stirring.  Exponential increase in viscosity with higher molecular weight.  Bonding discussed.  Hydration radius for PEG 4000 at 30C is 50 nm.  High mw PEGs  above PEG 1000 form random coils and low mw PEGS below PEG 600 maybe form stretched aggregate chains?  PEG on objects treated with high temps show signs of decomposition. 

Masuzawa, Fumitake and Yoichi Nishiyama.  “Experiments on the Impregnation of Waterlogged Wood with PEG Part II”  Conservation Science Bulletin.  Hozon Kagaku Kentyushitsu Kiyo.  Vol. 3 1974 pp39-46

Ellen Carrlee’s notes: this is from a literature review in ICOM-CC WOAM Newsletter No 8 Nov 1982.  Size greatly affects time for saturation: 50-60 days for 3cm wood, but more than 120 days for oak of 7.5cm

Masuzawa, Fumitake.  “Change of Waterlogged Wood Impregnated with PEG Along the Lapse of Time.”  Conservation Science Bulletin.  Hozon Kagaku Kentyushitsu Kiyo.  Vol. 3 1974 pp. 52-58

Ellen Carrlee’s notes: this is from a literature review in ICOM-CC WOAM Newsletter No 8 Nov 1982.    Reviewing wood treated with PEG after one year.  Wood treated with PEG 540 blend absorbed moisture, oozed out and there was shrinkage.  PEG 2000 showed radial cracks after 3 months and some expansion.  PEG 3300 showed no great change.  Based on other articles, they were probably looking at oak.

Murray, Howard.  “The Conservation of Artifacts from the Mary Rose.” Proceedings of the ICOM Waterlogged Wood Working Group Conference Ottawa 1981. pub 1982 pp. 12-19

Ellen Carrlee’s notes: Wood treated was poplar, oak, ash and softwoods.  Passive holding included spraying with boric acid and double wrapping in sealed polyethylene sheeting (dried out somewhat and got cracking and salt efflorescence within 6 months) or submersion in water (resulting in additional expansion and softening.)  Pre-treatment with 5% EDTA as well as ultrasonic cleaning to remove salts and iron corrosion products, although more than 48 hours in EDTA resulted in notable softening.  PEG 3400 up to 50%.  Mostly doing freeze drying, although getting good results with drying only the surface in the freeze drier and then allowing it to air dry.  Excess PEG removed with hot air, IR lamps, and ethanol swabs.  Reconstruction done with wooden dowels, nitrocellulose adhesive and melted PEG 6000 at 50% as a surface coating.

Rodgers, Bradley.  ECU Conservator’s Cookbook: A Methodological Approach to the Conservation of Water Soaked Artifacts.   Chapter 2: Waterlogged Wood.  Herbert P. Paschal Memorial Fund Publication.  East Carolina University.  1992. 

Ellen Carrlee’s notes: ECU= East Carolina University.  Dr Bradley Rodgers teaches conservation of material from underwater environments. Don’t put items from saltwater directly into fresh water, needs to be gradual or the salt water moves out faster than freshwater can move in, causing collapse (ie pruny fingertips in the bath.)  Specific gravity of several woods are given.  Pits in cell walls have valves, and if these are blocked it is harder to impregnate the wood.  Hard to see w/o SEM.  PEG solution is heated, and you weigh it weekly after you achieve 50% PEG.  Should stabilize at about 20% weight gain.  Might go up to 35%.  If you’re using PEG 3350, maybe even 45%  Wood in good condition sometimes as little as 15%.  Sucrose treatment described.  Brush coating of 50% PEG 3350 to consolidate the outer layer.  Ellen’s note: Bradley’s treatments don’t always match up to AIC standards and ethics, and there was a big dustup over one of his recent publications, an update and expansion of the material in this book.

Singley, Katherine.  The Conservation of Archaeological Artifacts from Freshwater Environments  Lake Michigan Maritime Museum, South Haven, Michigan 1988. 

Ellen Carrlee’s notes: She tends to use PEG 300 and 400 with 4500 applied later hot.  Recommends pretreating wood contaminated with iron salts with 3% perchloric acid, soaked for about a week.  This dissolves iron and opens up the pore structure to increase the penetration of PEG.  PEG 300 at room temp 10% for six months, then removed and wrapped in plastic with regular surface brushing of higher concentrations 3X a week increasing the concentration every two months until 80% reached.  Slow drying at high RH was used.  50% PEG 4500 paste was then applied with hot air.  This layer was thought to prevent oozing out of lower MW PEG.  She also uses 10% PEG 300, soaked for a year and then freeze dried. 

Viduka, Andrew.  Survey of Methods Used by Some Large institutions Specializing in the Conservation of Wet Organic Archaeological Materials.  Report as the 2002 Churchill Fellow: Winston Churchill Memorial Trust of Australia.  2002. 

http://www.churchilltrust.com.au/res/File/Fellow_Reports/Viduka%20Andrew%2020021.pdf.

Ellen Carrlee’s Notes: Viduka visited several labs and wrote up his observations.  Texas CRL sees, among other things, darkening of surfaces with high PEG concentrations as a disadvantage.  Parks Canada was looking at whether PEG modifies the crystal size of water.  Tara Grant at CCI has generally found air-drying to be unsuccessful.  Wooden material from Nydam Mose, 5^th C Iron Age site treated in Denmark, is highly deteriorated with only lignin remaining.  NMD is looking into sucrose, wood flexibility post-treatment, Cellusolve method, lots of vacuum freeze drying, review of old treatments, deacidification of low mw PEG timbers, experimental cold air drying.  On the Vasa, acid affected areas have white or yellow build-up and generally appear on areas treated with PEG 400 and not PEG 4000.  Remedial treatment is a spray with sodium bicarbonate and soda with a pH >10 and covered with plastic wrap.  Skuldelev ships were some of the earliest to be conserved with PEG 4000, and 40 years later, they still have a mw of 3900.  Using too high a mw on only slightly degraded wood is a problem.  Too much PEG would give a purple or blue sheen on the surface.  Longer immersion made bigger timbers darker than smaller pieces.  Heating for re-shaping caused darkening of the surface. Glenn McConnachie’s PhD reveals that even well-preserved waterlogged oak from the Mary Rose has 30% volumetric shrinkage after air drying. 

Vynckier, Jozef.  “Examination and Conservation of Basketwork from a Roman Well at Destelbergen”  Bulletin de’Institut Royal du Patrimoine Artistique Vol 8.  1965  (Flemish?) 

Ellen Carrlee’s notes: Linden bark basketry fragments immersed 4 months in carbowax 4000

Watson, Jacqui. “The Application of Freeze-Drying on British Hardwoods from Archaeological Excavations.”  . Proceedings of the ICOM Waterlogged Wood Working Group Conference Ottawa 1981. pub 1982

Ellen Carrlee’s notes: Fungal degradation in the cell wall contributes to splintering when freeze-dried.  Mineral deposition or replacement in outer layers is common in archaeological wood, especially with iron.  Sometimes these can be seen as casts of material that is now lost.  Chelating agents etc remove the iron.  But iron also interacts badly with PEG.  Early warning in this article of problems with iron salts and PEG. Even if the soil has low iron content, there is sometimes high iron content in the wood. Oak freeze dried after 10% PEG 400 for 4-6 weeks had deep cracks next to the rays, and some distortion and collapse in some small fibers.  Using 10% PEG 400 and 15% PEG 4000 resulted in less cross checking on the surface.  Wood that underwent freeze-drying without impregnation collapsed, and showed crystals (calcium and sulphur) that precipitated out that did not do so when PEG was used.  Pitting details in the vessels that are useful for ID were obscured after treatment with PEG 4000.  Mixed PEG solutions work best when using freeze-drying.

Young, Gregory S.  “Microscopy and Archaeological Waterlogged Wood Conservation.”  CCI Newsletter, No. 6, September 1990.  pp 9-11.

Ellen Carrlee’s notes: General overview of PEG treatment/ research.  Deterioration greatly improves the ability of PEG to penetrate and treat wood successfully, but most excavated waterlogged wood is only moderately deteriorated.  White oak, various cedars, and white ash are hard to penetrate, while aspen, cottonwood, alder and spruce allow greater penetration.  Caution with determining degree of deterioration from thin 3mm cross sectioned wafers of wood examined under the microscope, as the sample has a lot of disrupted wood cells and suggests more cell wall accessibility than there really is. 

Young, Gregory S. and Richie Sims. “Microscopical Determination of PEG in Treated Wood – the Effect of Distribution on Dimensional Stabilization.”  Conservation of Wood and metal: Proceedings of the ICOM Conservation Working Group on Wet Organic Archaeological Material and Metals.  Freemantle, Western Australia Museum. 1987  Pub 1989. pp109-140

Ellen Carrlee’s Notes:  Fluorescence microscopy.  25-35% PEG 200 and 3350.  Found less penetration with larger molecular weights.  Dimensional stabilization correlates with full impregnation of secondary cell wall.  Eight different species tested showed broad range of access to cell wall. 

Young, Gregory S. and Ian N.M. Wainwright.  “Polyethylene Glycol Treatments for Waterlogged Wood at the Cell Level.”  Proceedings of the ICOM Waterlogged Wood Working Group Conference Ottawa 1981.  pub 1982 pp.107-116

Ellen Carrlee’s notes: Shrinkage happens when hygroscopically bound water within the cell walls is lost when wood is below the fiber saturation point (FSP.)  Lower MW PEG is expected to stay in the cell wall, while higher MW PEG bulks the lumina.  Cobalt thiocyanate is a microscopical stain when dissolved in non-aqueous histological grade cedarwood oil.  The oil (cedrene and cedrol) is immiscible with both water and PEG.  It  dissolves the cobalt thiocyanate, but readily gives it up to the PEG in wood sections. 

PEG 400 (35%) in cell wall capillary matrix

PEG 3350 (60%) bulked cell lumina

PEG 540 blend (64%) in both cell wall and lumina  540=1450 + 300 together equal MW mixture

Over 3000 shouldn’t get into cell wall, above 2000, should be impeded somewhat.  MW below 400 penetrate better.  PEG must penetrate the cell wall for best dimensional stability.  Double bulking is good, though.

2007 Basketry Internship

http://www.museums.state.ak.us/documents/bulletin_docs/bulletin_27.pdf

Bulletin Vol 27 Fall 2007

The Alaska State Museum conservation lab hosted two interns for a basketry conservation project this summer.  Both interns were graduate conservation students finishing their second year of studies: Molly Gleeson from the UCLA/Getty Museum program, and Samantha (Sam) Springer from the University of Delaware/Winterthur Museum program.  These programs and the interns themselves provided the funding to come to Alaska.  The ASM provided the supplies and supervision.  In the first week, Molly and Sam brainstormed treatment solutions for the archaeological basketry fragments in the lab, and did a preliminary cleaning on a group of flattened spruce root work baskets that may become a study collection.  In the second week, curator Steve Henrikson assigned each intern two horrifically damaged baskets.  Molly worked on two Haida baskets collected by Lt. George Thornton Emmons in the late 1800′s.  The baskets had severe deformation, losses, tears, and old repairs of painted tape.  Sam’s Tlingit basketry projects also had intense tears, losses and deformation as well as old insect infestation and surface soiling.  The two Tlingit baskets still retain the inverted Y-shaped folds on the sides that indicate the baskets were folded for storage and thus not made for the tourist market.  Treatments included overall re-shaping in a humidity chamber, localized humidification with Gore-tex and blotter paper to align tears for repair with tiny splints of Japanese tissue and wheat starch paste, and innovative loss compensation with cotton gauze and sculpted paper pulp bulked with adhesive.  The interns were also able to examine baskets in the collection with Steve Henrikson and Tlingit-Haida weaver Janice Criswell.  Janice and weaver Mary Lou King twice took the interns “rooting.” They dug spruce roots, processed them, and each wove a basket under the tutelage of Janice and Mary Lou.  Together the interns formed quite a dynamic duo, becoming fast friends and helping Ellen make improvements to the lab.  Molly’s boyfriend Germán visited from Chile and proposed marriage on a beautiful Eaglecrest hike.  Germán and Samantha’s husband Seth also became friends, hiking and seeking satellite TV soccer matches while their partners immersed themselves in basketry.  Samantha’s professor Bruno Pouliot from Delaware also visited the interns for several days, and accompanied them to Sitka to kick off the second part of their internship.  Their first day on the job, they appeared on the radio to promote that evening’s free public program at the Sheldon Jackson Museum, a Conservation Clinic to provide advice to locals about their artifacts.  The clinic included ASM Curator of Museum Services Scott Carrlee (also a conservator.)  More than fifty people came, most bringing artifacts for examination, making the event one of the most successful public programs at the SJM in recent years.  In addition to several basketry treatments, the interns were able to meet with retired curator Peter Corey, National Parks Service curator Sue Thorsen, and Tlingit weaver Teri Rofkar to study baskets.  They also gathered materials and wove baskets with Teri.  In an exciting development, the interns are working with Teri and Janice to co-author a paper for an important international museum conference.  The International Council for Museums Conservation Committee (ICOM-CC) holds a major conference every three years.  In 2008, the conference will take place in New Delhi, India with the theme “Diversity in Heritage Conservation: Tradition, Innovation and Participation.”  The basketry abstract was provisionally accepted in July.  Only 40% of the proposed abstracts were accepted, and final paper is due in November for final review.  If accepted, this will be one of the very few professional conservation papers that will include a first-person Native voice, instead of the Native perspective only interpreted through a conservator.  Internships such as this one provide up-and-coming conservation professionals an opportunity to work with Native artists and museum professionals in the environment where the artifacts were made, allowing for multiple perspectives and a deeper understanding of the conservator’s sensitive role in preservation.  These are lessons that can be carried on throughout their careers.  In return, interns take on difficult treatments and share the latest techniques and theories in conservation they have learned in school.  Today’s interns are tomorrow’s professionals, linking us to museums in the lower 48 and creating a network of colleagues.  The long-range plan for the ASM conservation program includes dividing the collection into materials groupings for systematic surveys.  Each survey will identify priorities for conservation treatment and provide ideal internships for future conservation students.  Next summer’s project targets the museum’s natural history collection.  Stay tuned…

Rim of spruce root basket 2006-18-1 BT by Samantha Springer

 

After treatment by Samantha Springer using Japanese tissue and paper pulp with wheat starch paste and watercolor.

 

 

 

 

 

 

Molly Gleeson inventing a new repair technique using cotton gauze, paper pulp, Japanese tissue, wheat starch paste and PVA emulsion adhesive.

After treatment of large loss near base of Haida basket II-B-493

 

Janice Criswell teaches Samantha Springer to weave spruce root in Mary Lou King's kitchen.

Top 10 Projects: March 2013

Egads!  This list gets later every year!  And I have not posted on the blog in a full year.  Time flies indeed.  Here’s what’s up with me and my conservation world here in Juneau, Alaska…

1. COLLECTIONS MOVE

Construction has begun on our new storage vault for the new Alaska State Library Archives and Museum building (SLAM).  They are making the storage vault first (walls are going up right now!) and we are getting ready to move all 30,000+items in the collection and on exhibit out of the building beginning March of next year.  And we have only SIX WEEKS to move everything out.  This is because they need to tear down our building to make way for the rest of the new structure.  Our museum has a staff of only eleven people, so it is going to be an interesting operation to move everything to the new storage vault safely.  To help visualize the logistics, I used my son’s Legos to create a model…

Lego model of collection move logistics

2. LAB MOVE

Did I mention they are going to bust a hole in the basement wall of the museum and create a tunnel to the new storage vault?  Guess whose conservation lab is in the way?  So I will be moving my lab into temporary quarters in the next few months.  This lab has been here since 1976 and I have a LOT of accumulated goodness to move.  Not to mention getting set up in a new temporary space for the next two or three years.  The new exhibits are supposed to open in May of 2016, and of course new exhibits have lots of conservation needs.  Here’s hoping the temporary lab can handle the workflow.

Shipwreck garments drying in lab

3. LOCOMOTIVE

Mining is an important part of the history of Alaska, and we were lucky to receive a donation of an original locomotive from the heyday of Juneau hard rock gold operations.  It was donated by the California State Railroad Museum a few years ago.  It had been significantly altered during its time with the Santa Cruz Cement Company and needs significant restoration, but will be an important part of the new exhibit galleries.

Baldwin locomotive in storage

4. LIGHTHOUSE LENS

Our 3rd order Fresnel lighthouse lens is not in bad shape, but it wil be a delicate operation to move it.  Formerly located within Cape Spencer Light Station in S.E. Alaska from 1925-1974, it was made and constructed by Barbier, Bernard and Turrenne of Paris.

Large, heavy, and made of glass

5. GUTSKIN PhD

I continue to chug along on work for a PhD in anthropology, with a focus on the cultural meanings of internal organs of marine mammals.  Those would include organs like stomach, intestine, bladder, and esophagus from animals like seals, walruses, and sea lions.   Yup’ik, Siberian Yup’ik, Inupiaq, Alutiiq (Sugpiaq), and Aleut (Unangan) cultures all have traditions of making items like rain parkas, sails, windows, containers and drums out of these materials, but they are rarely used today and poorly understood in musuems.  I am hoping to work with Native people to understand the meanings of these materials better.

Roll of bearded seal gut at Cama-i 2013

6. BETHEL

Just last week (March 21-25) I went to Bethel with my 5-year-old son, Carson, to see the Cama-i dance festival and meet the new director of the Yupiit Piciryarait Museum, Eva Malvich.  I had never been to that part of the state before, and was eager to see if there might be possibilities for collaboration between our two museums as I work on the gutskin project.  It was the most amazing experience to be there…the people were just wonderful and I really look forward to going back.  I am heartened that people do seem interested in this kind of project, and it seems that I might have something I can give back with my knowledge of conservation and museum practices.

Yupiit Piciryarait Museum and Cultural Center in Bethel, Alaska

7. MATERIAL CULTURE

In order to begin the gutskin project, I need to write three synthesizing papers for my PhD program at the University of Alaska Fairbanks.  These papers will give me some background helpful to the dissertation, and are meant to be a survey and analysis of what the anthropological literature says about certain topics I ought to develop some expertise in.  The first of them for me will be about material culture.  The next one will be about Alaska Native relationships with marine mammals, and the third will be about practice theory

Beautiful gutskin basket by Elaine Kingeekuk for sale in the Sheldon Jackson Museum gift shop in Sitka, Alaska

8. BASKETRY AT WOAM

After quite a long haul, I will be presenting a paper at the WOAM conference on the final results of PEG treatments on ancient baskets at the Alaska State Museum.  Dana Senge and I have been working on this topic for quite some time, and will be co-authoring the paper.   WOAM is the acronym for the Internation Council on Museums Conservation Committee working group on Wet Organic Archaeological Materials, and the triennial meeting is in Istanbul, Turkey this year.  My husband Scott Carrlee (also a conservator) and I both had terrific experiences doing conservation fieldwork in Turkey in the 1990′s and are really looking forward to showing our son the joys and pleasures of Turkey.

Ancient spruce root basket during treatment at the Alaska State Museum

9. SHIPWRECK TREATMENTS

Hoo boy, all the above would be plenty if it were not for the twenty-odd big totes of wet shipwreck materials awaiting treatment in off site storage.  They froze solid last fall while I was in Fairbanks (leave of absence to take coursework for the PhD) and are just now beginning to thaw.  I have thawed out the five most troublesome ones,  I think, and the materials are in an amazing state of preservation.  The wreck was a gold rush era luxury steamship, and we have leather, textiles, ceramic, glass, rubber, tools, jewelry and more.   I’ve dried out two full suits (jacket/ vest/pants) and numerous other garments, very similar to the ones in the 1902 Sears catalog.  My favorite item so far is an amazing doll about 9″ tall that I believe is made of gutta percha.  The doll is over 110 years old, and in remarkably good condition.  I will be putting it in anoxic storage to slow the deterioration of this material.

Doll, circa 1900, made of gutta percha or rubber

10. EDENSHAW ARGILLITE LOAN

Stay tuned on this one…the Alaska State Museum and its branch in Sitka, the Sheldon Jackson Museum, have loaned several important masterpieces to the Vancouver Art Gallery for a major retrospective exhibition of the argillite masterworks of Haida artist Charles Edenshaw.  The descendants of the artists are involved in the exhibition and catalog, and the artworks will be accessible to many more Haida people than ever before.  However, argillite is a strange material, a carbonaceous shale from a single quarry in Haida Gwaii, the homeland islands of the Haida people.  The quarry no longer produces large pieces, so the number of large artifacts made from argillite are limited.   Argillite is barely stone, and still retains some properties of clay, including being humidity sensitive.  The ability to exapand and contract with changes in humidity is different in different directions due to the bedding plane layers of the material.  When it breaks, the break edges are often crumbly.  One artifact in particular, a large compote, has a diagonal fault line of quartz through its load-bearing pedestal.  After a long and careful decision-making process, musuem staff decided the value of sending the artifacts to be seen by Haida people was worth the substantial risks to the artifact.  I think it was the right decision, but really nerve-wracking for a conservator!

Charles Edenshaw argillite compote

Top 10 Projects: March 2012

Spring already and I haven’t updated what I’m up to this year!

1. NMAI IS COMING!

The patch on this basket looks just like a basktry start.

Conservators and staff from the National Museum of the American Indian are collaborating with Tlingit weaver Teri Rofkar to link source communities with the conservation of indigenous materials.  The goal is to help change the paradigm for collections care.  With basketry as the focus, they seek to incorporate cumulative history, geography, climate, material harvesting/ processing, indigenous technologies, Native science and living culture into the way museums are caring for and thinking about baskets.  Here at the ASM, staff hope to examine historical and archaeological baskets here with the NMAI visitors and local weavers.  I have so many questions for them!

2. PEG HOME STRETCH

When using high concentrations of high molecular weight PEG, an unexpected benefit is the control of final color that is afforded with combinations of ethanol and warm water to remove excess PEG from the surface.

After years of pondering, experimenting, and collaborating with conservator Dana Senge, the last of our waterlogged baskets are finally undergoing PEG treatment.  These very deteriorated spruce root baskets (thousands of years old) can be successfully treated but it seems that one must choose between a basket that is rather spongy/delicate or brittle/delicate.  Once I get this group finished and can compare the range of efforts, you’ll see a posting on it.

3. TORRENT HOME STRETCH

A satisfying set of silver nitrate tests for chlorides in the sodium sesquicarbonate wash waters.

More than 80 artifacts that were recovered from the 1868 wreck of the Torrent a few years ago, and only a few of them are still in treatment.  I was most thrilled that the slooooow old-school sodium sesquicarbonate treatment I used on the copper alloys appears to have worked.  I compared the wash waters I saved using the silver nitrate test for chlorides, and it does indeed look like we had a peak in chloride removal during the middle of the treatment.  A bronze mountain howitzer has come back from the Texas A&M lab and the loving attention of Jim Jobling and his crew.  They are undertaking electrolysis for two of the portholes, while I did the sodium sesquicarbonate on the other two.  Hoping to give y’all a posting on the comparisons and pros/cons of the two methods.

4. MOLD

Mold on feathers

During Crista Pack’s 2011 summer project, we found mold on a few artifacts.  It was a weird mystery that is described on the “What’s That White Stuff?” weblog, as well as a link to her research paper the subsequent semester explaining what is likely happening.

http://alaskawhitestuffid.wordpress.com/2012/03/28/a-fungus-among-us/

5. NIMBUS

Scott Carrlee cleaning Nimbus on a sunny day in 2004

The museum’s Robert Murray sculpture Nimbus needs its springtime washing.  And Nimbus now has its own Facebook page some clever citizen began recently:

http://www.facebook.com/pages/Juneau-Nimbus/341127159252716

There is a plan afoot to work with the artist (Murray) and fabricator (Lippencott) to give Nimbus some TLC.  It could use better positioning on its site, repairs to areas that have a tendency to catch water and rust, a badly needed new paint job, and maybe even reattach the dimensions lost when the sculpture was unceremoniously chopped down with a blowtorch.  Nimbus has a long and chequered history in Juneau, and it’s been a while since the public art/ what is art for/ what does this sculpture mean discussion has taken place.  It is sure to be lively, and the possibility of the artist and fabricator being involved is beyond thrilling.

6. LEATHER DRESSING POSTING

Disfiguring fatty bloom on leather that was treated with a dressing in the 1970's.

There are still folks in Alaska who put leather dressing on their collections.  Stay tuned for a posting aimed at the Alaskan museum collections care audience about WHY we don’t recommend this anymore. 

7. THEATER ORGAN PLANNING

Theater Organ in the State Office Building, Juneau Alaska.

One of the more unusual objects in our collection is a 1928 Theater Pipe Organ made by Kimball.  Theater organs were intended to accompany silent films, and allow a single musician to control an amazing array of instruments from the console: not only the pipe organ, but an upright piano, a percussion section, woodwinds, and “all the bells and whistles.”  You can read more about the organ here: http://www.pstos.org/instruments/ak/juneau/20thcentury.htm

After various adventures, it was saved and restored by a committee of engaged citizens.  The organ and a custom-built chamber are now in the public atrium of the State Office Building, where organ concerts are performed every Friday over the noon hour.  The organ became part of the Alaska State Museum collection in 1975 in order to protect and preserve it.  The time has come to develop a long range plan for its regular maintenance and tuning, which has happened on an irregular basis for decades. 

8. ICOM-CC ETHNOGRAPHIC NAME CHANGE

Is the title of this working group as much a dinosaur as this wind-up pencil shrpener I won at a WAAC silent auction? (oh c'mon, how would you illustrate this topic!?)

At the 2008 ICOM-CC Triennial Conference, keynote speaker Tharron Bloomfield (Maori) lit the fuse.  I’m copying his quote:  “The term ‘ethnographic’ conservator is at best old fashioned and inadequate, and at worst offensive and racist.  The word ethnographic suggests it is the culture of ‘them rather than us’, it also makes a judgment that one culture is superior to another.  Why are the clothing, weaponry and tools of my ancestors described as ethnographic, while the clothing, weaponry and tools of someone from a European culture not?  It is time for conservators who work with the cultural material to find another, more appropriate name for the material they work with.”  I’ve been a member of the Name Change Committee, and the international discussions have been hugely eye-opening to me.  I think when the committee presents its work and the ICOM-CC working group votes on this name issue, we will be watched with interest by many outside the profession.

9. LITTLE-TRIPLE-A

Pinniped bone specialist Mike Etnier leads the Alaska Consortium of Zooarchaeologists on a tour of some collections at the Burke Museum, including this Upupa epops (hoopoe).

For the third year in a row, I attended the Alaska Anthropological Association conference in an attempt to better understand the field of anthropology and build bridges.  It took place in Seattle, and included behind the scenes tours at the Burke Museum and NOAA’s Marine Mammal Research Collection.  One of my favorite groups of people there is the Alaska Consortium of Zooarchaeologists, who as you can imagine are nuts about bones and not afraid to get their hands dirty.  There are also gems like Dr. Claire Alix, a wood specialist who knows all kinds of amazing information about the kinds of wood that washes up as driftwood on the shores of Alaska, where it comes from, and how long it takes to get there.  There was a whole group of talks about very early explorer/collectors in Alaska, what they were up to, and what happened to their collections.  Here’s an interesting set of numbers to share.  Of 160 authors described in the program, 63% were from academia, 16% were Cultural Resource Management (CRM) archaeologists (in the business of excavating in advance of development according to federal regulations), 12% worked for government, 7% worked for museums, and 2% were Native. 

10. PURSUING A DOCTORATE IN ANTHROPOLOGY

Some ANTH 475 textbooks: Haa Kusteeyi: Our Culture by Dauenhauer and Dauenhauer; Take My Land Take My Life by Mitchell; Engaged Resistance: American Indian Art, Literature and Film from Alcatraz to the NMAI by Rader; and Methodology of the Oppressed by Sandoval.

In January 2012, I was accepted into the PhD program in Anthropology at the University of Alaska Fairbanks (UAF).  I will be on campus full-time for the Fall of 2012, and hoping to do the rest of the coursework from Juneau.  I’m taking two courses now.  ANTH 606: Mythology and Folklore from an Anthropological Perspective is a UAF course offered in Juneau through videoconferencing with the class in Fairbanks. In fact, there is a small contingent of scholars taking the class here, including Anastasia Tarman Lynch, from the Alaska State Library’s Historical Collections (also pursuing a PhD in anthropology), Zachary Jones from the Sealaska Heritage Institute (pursuing an interdisciplinary PhD focused on ethnohistory) and Daniel Strong, also from the Sealaska Heritage Institute (pursuing an MA in anthropology).  The other class I’m taking is on the Juneau campus, ANTH 475: Alaska Native Social Change.  It is an undergrad class, and taking 6 credits while working full time is nearly killing me, but I think you’ll know why I HAD to take this class when I mention the professor, Lance Twitchell, is Alaska Native himself and is offering perspectives I have never had before in an academic setting.

Collections Labeling: Material by Material

This is the manual included in a kit I made for a workshop at the Museums Alaska conference in Valdez, September 2011.  The 2011 workshop was funded through a grant from the Alaska State Council on the Arts.  The kit is designed for small museums with wide-ranging collections with everything from natural history specimens to fine art, where limited staff must wear many hats.  My preferences come from (1) labeling thousands of artifacts while I was a curator at the Juneau-Douglas City Museum and (2) providing outreach assistance to museum staff statewide in Alaska who need easy simple solutions to collections management issues.  In general, I follow the paper label technique described by Thomas Braun in JAIC Summer 2007. The text below is from the little manual I enclosed in each kit.  If you want the little manual, just print out this manual for collections labeling , cut it in quarters and staple it together.  The contents of the kit are listed and explained in the posting Collections Labeling: Simple Kit.   Some adhesive choices are described in the posting Collections Labeling: Alternate Adhesive Testing.

Here's a labeling challenge: a box of muskox fur!

The back cover of the manual includes these questions to help determine the best labeling technique:

1. Will applying this label cause damage such as new holes or dissolving the surface?

2. Will future removal of this label cause damage?

3. Will the labeling materials run, fade, abrade, corrode or age in a way that will damage the artifact?

4. Is the label readable?

5. Is it easy to find the label without having to handle the object a lot?

6. Is it easy to hide the label during exhibition or photography?  Is the label ugly?

7. What will happen if the label gets wet?

8. Is the label likely to come off with normal handling, running, or abrasion?

9. Is there a compelling and urgent reason to remove any existing labels that may be important to the history of the item? 

ANTLER, BONE, IVORY, TOOTH

• Beware, sometimes synthetic materials are made to look like this.  See “PLASTIC”
• Locate a smooth area that is not flaking, powdery or decorated.
• Choose a location that will not show during exhibit or photography.
• Apply base coat of B-72, paper label, top coat.
• Use paper tag, labeled bag/ box as redundancy and to reduce handling.

BALEEN, CLAW, HOOF, HORN

• Beware, sometimes synthetic materials are made to look like this.  See “PLASTIC”
• Locate a smooth area that is not flaking, powdery or decorated.
• Choose a location that will not show during exhibit or photography.
• Apply base coat of B-72, paper label, top coat.
• Use paper tag, labeled bag/ box as redundancy and to reduce handling.

Sometimes the tag is the redundant label on a basket, sometimes it is the only label.

BASKETRY

• Typically, the underside of a basket is labeled and the inside of the lid, if present.
• Choose a location that will not show during exhibit or photography.
• For baskets with very large elements, like cedar bark mats or bark containers, apply base coat of B-72, paper label, top coat.
• For baskets with a finer weave structure, do not use adhesive but instead a small hanging tag sewn in between the weave with a needle that may pass through easily.
• Use labeled bag/ box as redundancy and to reduce handling.

Redundant label on the folder means less handling for the item itself.

BOOKS and PAPER

• Inside cover and reverse of title page are the common places to mark a book. Writing on the top outer corner means the book doesn’t have to be opened all the way.
• Number is usually applied to the back upper right corner of a sheet of paper such as a document or a print/drawing/ watercolor.
• Choose a location that will not show during exhibit or photography.
• Avoid labeling in an area that already has information written there (price, owner’s name, signature, etc.)
• Apply number with a #2 or HB pencil, taking care not to press hard enough to make indentations. Write on a firm surface.
• Use a labeled bag/ folder/ box as redundancy and to reduce handling. Insert an acid-free paper bookmark with number in pencil at the top to fragile books.

CERAMIC

• Typically, the underside of a ceramic is labeled unless it is unusually large or heavy, and then a place is chosen low on the “back” side.
• Locate a smooth area that is not flaking, powdery, painted or decorated. The smooth, hard, shiny exterior of some pottery, called glaze, is made of glass and can be labeled.
• Beware painted surfaces and do not mark or adhere onto them.  Do not mark break edges of sherds.
• Choose a location that will not show during exhibit or photography. Do not obscure maker’s marks on base.
• Apply base coat of B-72, paper label, top coat.
• Use paper tag, labeled bag/ box as redundancy and to reduce handling.

It is possible to safely label leather and gut, but I consider it a more advanced skill set and generally recommend a paper tag.

FEATHER, FUR, GUTSKIN, LEATHER

• Feathers of significant size may be labeled on the quill with a small font paper label.
•  Most feather and skin artifacts have delicate surfaces and the removal of an adhesive label will leave a stain.
•  Many feather and skin artifacts are connected to composite objects with other parts that may be labeled instead.
• Some feather and skin items are sewn and a Tyvek label sewn through original stitch holes with white cotton thread may work, using the technique recommended for garments and textiles.
• Stitch each end of the label so minimal snips are needed for removal.
• No new holes shall be made. If no technique above will work, use a paper tag or label the enclosure.
• Taxidermy is typically labeled with a tag around the leg, and also the mount support if present.

I like the collections management solutions offered by labeling a coin holder used for glass beads.

GLASS

• Typically, the underside of a glass vessel is labeled.
• Large beads may be labeled with a tag on a string.
• Locate a smooth area that is not flaking, powdery or decorated. Do not mark glass that suffers from glass disease (weeping, crizzling, etc).
• Choose a location that will not show during exhibit or photography. Small font size on paper label helps.
• Apply base coat of B-72, paper label, top coat.
• Use paper tag, labeled bag/ box as redundancy and to reduce handling.

I think B-72 loves metal more than any other material.

METAL

• Typically, the underside of a metal item is labeled. If the metal item is very heavy, the “back” may be labeled instead.
• Locate a smooth area that is not flaking, powdery, rusty, decorated, or coated. Musical instruments are often coated, for example.
• Coins are usually not labeled directly. Edges may be labeled if large enough.
• Choose a location that will not show during exhibit or photography. Small font size on paper label helps for smaller objects.
• Apply base coat of B-72, paper label, top coat. Avoid artist acrylics and adhesives containing ammonia with copper or alloys with copper such as sterling silver.
• Use paper tag, labeled bag/ box as redundancy and to reduce handling.
•  Jewelry may be especially difficult to label, even with tiny font size. Redundant tags are helpful.

Did I mention I love redundant tags to minimize handling?

PAINTINGS

• The back upper right hand corner of a painting is a good place for the number.  Large paintings may be marked on diagonal corners.
• Artworks are sometimes removed from frames, so the back of the painting support is the best location for marking. Select a section of the wooden stretcher or strainer, plain wood if available.
• Avoid touching the back of the canvas corresponding to the painted area. Label the rigid edges or backing board if the support is not visible.
• Apply base coat of B-72, paper label, top coat.
• In addition, use a paper tag attached to the screw eye, D-ring or other hanging hardware. This allows a painting to be identified without excessive handling.
• Collector and exhibition labeling/ marking on paintings has a long and important tradition.  Avoid removing old labels from the backs of paintings.

PHOTOS

• Number is usually applied to the back upper right hand corner, in a non-image area along the edge.
• For paper, apply number with a #2 or HB pencil, taking care not to press hard enough to make indentations. Write on a firm surface.
• For photos made of plastic, use the blue photo pencil.
• Sometimes, the right amount of dullness on a graphite pencil will also work on plastic but care must be taken not to scratch the plastic.  If the plastic has oily fingerprints, plasticizers, or coatings, pencil will not work well.
• Use a labeled enclosure such as a bag or folder as redundancy and to reduce handling.

Acetone damaged all these plastics. Water-based labels often peel off too easily. I prefer tags for plastics.

PLASTIC

• Many kinds of plastic are vulnerable to the solvent acetone used in B-72 labeling adhesive, so this adhesive should not be used.  Some older plastics are sensitive to water-based adhesives.
• It can be difficult to identify specific plastics.  Rubber, vinyl, plastics, and synthetic materials should be marked with great caution as removal can cause damage.
• Adhered labels often pop off of flexible plastics.
• Many plastic items are connected to composite objects with other parts that may be labeled instead.
• For a completely plastic object, the most conservative recommendation is to only use a paper tag with a labeled bag/ box as redundancy.  Enclosures also reduce handling, and many plastics age poorly so the less handling the better.
• Some museums use water-based acrylic adhesive labels, or B-67 in petroleum distillates, but removal of these labels is not risk-free.

This Melvin Olanna marble sculpture (ASM 2000-6-2) is heavy! Don't put the label underneath, or you risk damaging the artwork or yourself looking for it.

STONE

• Typically, the underside of a stone item is labeled. If the stone item is very heavy, the “back” may be labeled instead.
• Locate a smooth area that is not flaking, powdery or decorated. Porous or rough surfaces are difficult to label. Avoid use edges of stone tools.
• Choose a location that will not show during exhibit or photography.
• Apply base coat of B-72, paper label, top coat.
• Use paper tag, labeled bag/ box as redundancy and to reduce handling.

Blank Tyvek tag showing loops at the ends that are easy to snip for removal.

 

These are labeled at the inner back of the collar, but a redundant tag on the hangar reduces handling.

 

For rolled textiles, redundant tags are really needed.

TEXTILES and GARMENTS

• For textiles robust enough and large enough to hold a label, a sewn technique with Tyvek and white cotton thread is recommended.
• Garments are typically labeled where a manufacturer’s label might be found, such as at the back of a neck or the waistband.  Labeling diagonal corners is helpful for large rolled textiles.
• Choose a location that can be hidden during exhibit or photography.
• Cut a piece of Tyvek, write the number by hand with a Zig Millenium fade-proof and waterproof pen in the center, leaving room for stitches at each end.
• Use seams and original stitch holes whenever possible. Second best is to pass the needle between the weave without piercing the yarns.
• Stitch the label with a loop through two holes at each end so minimal snips are needed for removal.  Sharp needles work well to pierce Tyvek, while ballpoint needles are less likely to damage the textile fibers.

Each rattle also has its number written in pencil on the pallet that holds it.Redundant paper tags in each dish reduce handling and facilitate locating an item.

WOOD

• Wood items are often painted, varnished or otherwise coated.  Avoid applying a label to those areas and seek out an inner, underside, or back surface that is bare wood.
• Locate a smooth area that is not rough, splintery, or decorated.
• Choose a location that will not show during exhibit or photography.
• Apply base coat of B-72, paper label, top coat.
• #2 or HB pencil may also be used on wood if the number can be applied without denting the wood and if it may be removed again with an eraser. Pencil, however, tends to be harder to read.
• Use paper tag, labeled bag/ box as redundancy and to reduce handling.

Top 10 Projects: January 2011

Can you believe I missed writing Top 10 for 2010?  Wow, time flies.  Here are the things on my to-do list for 2011:

Brass sabots are all that remain of Parrott shot from the 1868 Torrent shipwreck. They are soaking in sodium sesquicarbonate to remove harmful chlorides.

1. TORRENT SHIPWRECK ARTIFACTS  These came out of the ocean in the summer of 2008, and many are still in the treatment phase.  The bone brush is done (thanks to intern Lauren Horelick, who performed an Acrysol WS-24 treatment.  It was on exhibition last summer.)  The scale rod is also done, thanks to a successful electrolysis by State Archaeologist Dave McMahan.  It was also on display last summer.)  All the lead is dry and seems to be stabilized.  By this I am talking about our minie balls, spherical case shot, so-called “sounding lead” and a few other munitions-related things.  They had been in fresh water longer than they ought to have been, and fresh water contains dissolved gases that promote corrosion.  We knew this was happening because we saw a subtle glittery slick on top of the water and even a few crystals coming out of the lead itself on one of the artifacts.  Removal from water and drying halted that process, but there is still a slightly glittery quality to the surface of the lead that I am contemplating treating.  The brass artifacts are all currently soaking in sodium sesquicarbonate.  In addition to some small finds, there are two portholes soaking in this solution.  There are two more portholes undergoing electrolysis in the lab at TAMU.  TAMU (Jim Jobling) is also taking care of the bronze mountain howitzer by electrolysis for us.  Stay tuned for more about the ship’s toilet (!)

Bones for testing adhesive labels

2. INTERFACE WITH STATE ARCHAEOLOGISTS  The Alaska Anthropological Association Conference is March 9-11, 2011 in Fairbanks.  I am looking forward to this with great excitement.  I am still learning how the world of archaeology operates in Alaska, and I was hoping to write a posting from last year’s conference, but I was way too green and decided to keep my mouth shut and ears open.  This year I’ll bring a poster about adhesives for labeling artifacts and participate in a session about conservation of archaeological artifacts from the maritime environment.  Last year I participated in a session about conservation and curation, and heard great complaining about using B-72.  Checking with my colleagues, this is widespread among archaeologists.  They want to use other adhesives instead.  So we are doing some very qualitative testing on mock-ups of bone, ceramic, stone, metal and wood using the paper-label process.  Anna Weiss, a conservation grad student in the Queen’s Program (and my AIC mentee!) is doing the first run, Samantha Springer (objects conservator at the Cleveland Museum of Art, Winterthur/Delaware grad and a 2007 basketry intern in my lab) is running another set of tests.  And I’ll run a third set.  Then we’ll have a poster at the conference and think about how to disseminate the info.

Working on defining various air handling unit zones for a new facility.

3. NEW BUILDING PLANNING  Sounds dry, doesn’t it?  Not at all.  We are in the design phase of a new building here in Juneau, Alaska that will combine the Alaska State Library, Archive and Museum in one facility.  You can read about the project here at http://alaskalamp.blogspot.com/.  My role right now is to work with the team to understand collection and conservation needs.  For example, working with lab planner Roz Estime to develop the objects lab as well as help with the paper lab.  Let me remind my gentle readers, Alaska has only a handful of conservators, and none of them do paper/books/photos with the exception of nomadic conservator Seth Irwin, who Scott Carrlee recently brought up here to do contract work at various institutions.  Right now, Seth has found an ally and fellow creative-thinker in Norm Legasse, the head of the Alaska Aviation Heritage Museum in Anchorage.  Seth’s work featured prominently in the news recently about important historical watercolors from Barrow.  I’m also working with the project’s mechanical engineer, Dave Shumway, to get him the info he needs to set up the HVAC system.  ASHRAE chapter 21 should be required reading for conservation graduate students.  If you want to talk with engineers about HVAC (and c’mon, who is doing the HVAC?  So whose ear do you need to bend?  The engineer!)  you have to know this chapter.  The 2007 version is getting updated in 2011.  One thing I had never heard of before but is hugely eye opening: pressure diagrams.  Square one for designing an HVAC.  And overlooking the pressure diagram is one of the causes of problematic indoor climates.  There’s another angle that I am approaching from regarding a unified building. Working with the various worksites of libraries, archives, and museums in our division (right now that’s about 8 different locations) to unify our emergency preparedness (hooray for the Incident Command System!), our Integrated Pest Management, and our environmental monitoring.  Just last week, I sent new PEM2 dataloggers to each site.

PEM2 datalogger on the left and HOBO Pro datalogger on the right

4. PEM2 DATALOGGERS  We bought a pile of these loggers to replace our old HOBO loggers, which were 10 years old.  I think we will continue to use the HOBO loggers (which I like a lot) for spot checking and specific applications, but the PEM2 loggers have some advantages for us.  People at the 8 different sites can download the loggers using a plain ordinary thumb drive, and load them right onto a free website.  I can look at them right there, and run some of the IPI’s preservation metrics to evaluate the quality of their preservation environment.  I can also get the datafile emailed to me and run the info on the proprietary software from IPI called “Climate Notebook.”

Common raven, Alaska State Museum collection I-B-359, tested positive for arsenic

5. SURVEYS CONTINUED  I began surveys of the basketry and natural history collections back in 2007 and something always pulls me away from those two projects (or physically blocks the space!)  Each is about one-third complete.  The natural history survey, in particular, has some pressing needs regarding protection of taxidermy, arsenic testing, and sorting out some registration issues ahead of some exhibition needs we may have involving that collection in the future.  There may be some research and access activities going on with our herbarium in the near future as well.  With both surveys, interesting patterns are emerging that will be interesting to review once the surveys are complete, and of course priorities for treatment will become obvious as well.

Typical interior of a very old kayak

6. KAYAKS ARE COMING!  Several traditional skin boats are on their way to Juneau.  Some will become part of the Alaska State Museum collection, and others will be sent on to other museum collections in Alaska.  Because there are so few conservators in Alaska, and our institution performs a lot of outreach and support, I am hoping to perform basic condition reports on the outgoing kayaks as a courtesy to the institutions who receive them, since they may someday ask our advice in how to care for them.  I am especially interested in kayaks and large organic artifacts post-conservation-treatment, as they seem to have a period of convalescence in which stresses seem to be re-distributed over time, sometimes going through several seasons or even a couple of years.  I am eager to track that kind of thing for the next kayak treatment that comes my way.

Jacket made from a ringed seal in the Alaska State Museum collection, in need of treatment for large tears

7. FUR PARKAS WITH ACCESS ISSUES  We’ve got two fur parkas in the collection that are lined, but also have tears in the skins.  The repair of those tears will be tricky.  One seems to be made of muskrat skin, and the other is ringed seal.  One of them has fur cuffs that are crumbing because the skin is in such poor condition.

Example of an annotated image from the Alaska Fur ID Project. This is a guard hair from a Stellar Sea Lion, magnified 200X

8. ALASKA FUR ID PROJECT  I began this project in 2009 with intern Lauren Horelick, and we will be presenting a paper about it at the 2011 AIC conference in Philadelphia at the beginning of June.  The project is a free online resource with approximately 50 Alaskan mammals and includes various tools, references, and images (including under the microscope) to serve as a virtual reference set for conservators and allied professionals attempting to identify furs.   Lauren and I would like to turn our analysis of the possibilities and limitations of this kind of fur ID into an article for peer review, perhaps as an AIC article.  I am passionate about the idea of regional material identification resources on the internet, and if this works I want to be doing more of it with other materials.  For example….

Native-processed sea lion esophagus, Alaska State Museum II-A-3069

9. GUTSKIN PROJECT  For the past couple of years there has been a buzz in the world of ethnographic objects conservation about the need to better understand the internal organs of marine mammals and how they are utilized in ethnographic artifacts.  Recently there has been research on several fronts (I think we’ll hear more in the next ICOM-CC Newsletter?  I’m talkin’ to you, Amy Tjiong!) and there is talk about the need for collaboration and good communication.  I’m well placed in Alaska to help in this effort, but I don’t want to jump the gun yet (hoping for a conference call on this soon)  so stay tuned.

Low molecular weight polyethylene glycol for stabilization of waterlogged wood

10. ARCHAEOLOGICAL WOOD AND BASKETRY  I’ve got quite a few waterlogged wooden artifacts as well as an ancient waterlogged spruce root basket that are undergoing PEG treatment.  The wood is undergoing the old standard PEG CON method, but the basket I am treating according to the results of my experiments last year that were presented at the ICOM Triennial for Wet Organic Archaeological Materials.    My co-author Dana Senge continues to sleuth out the issues around waterlogged archaeological basketry as well.  This round of treatment ought to tell us whether these very degraded old baskets do better with a higher percentage of high molecular weight PEG than they did with some low molecular weight PEG and just a little bit of high molecular weight PEG.  I also will find out if Butvar B-98 works as well on consolidating a basket under-treated with PEG as it did on our test fragments.

Adhesives Inventory July 2010

ADHESIVES INVENTORY July 2010

Alaska State Museum

Ellen Carrlee, Conservator

 

PURPOSE OF THE INVENTORY:

1. I like to scan the list before selecting an adhesive for treatment to make sure I am considering all my alternatives.

2. Keeping obsolete adhesives helps me think about what may have been used on an artifacts in our collection, as well as monitor its aging under natural conditions on the lab shelf.  If something looks like hell in the bottle, I have to wonder how it is faring on the artifact.

3. The inventory lets me know at a glance if I have a certain adhesive so I do not re-order something we already have and waste money.

 

WATER-BASED ADHESIVES:

Acrylic Medium Gloss Daniel Smith 8 oz plastic jar

Acrysol WS-24 1 gallon plastic jug, nearly full still liquid but quite old from Rohm and Haas in Philadelphia.

Acrylic disperson for waterlogged bone consolidation slightly acidic, polyacrylic acid w/ acrylic copolymers or sodium polyacrylate.  Neutralization with any base causes it to clarify and thicken.  Dries transparent, colorless, hygroscopic and slightly brittle.  pH 7-7.5?

Acrysol WS-24 1 quart liquid in a HDPE plastic jug June 2010

Aquazol 500 100g bag of dry resin beads from MuseuM Services Corp June 2010

Aquazols are made of poly(2-ethyl-2-oxazoline). Soluble in water as well as polar organic solvents. Hot melts, liquid adhesives, consolidants, transparent coatings, and gessos

Aquazol 100 100g bag of dry resin beads from MuseuM Services Corp June 2010

Aquazol 50 100g bag of dry resin beads from MuseuM Services Corp June 2010

BEVA D-8 dispersion  Large plastic jar approx 1 pint Conservator’s Products Company (Talas) 2009

nonionic high viscosity adhesive. BEVA® D-8 is an emulsified mixture of ethylene vinyl acetate. It is used as a wet adhesive and as a hot-melt

BEVA gel in small plastic film-canister with original label, a sample?  Dried, yellow, old

aqueous dispersion of BEVA® 371. BEVA® Gel contains 25-50% water mixed with ethylene vinyl acetate and acrylic resin in a thixotropic gel. It is a contact adhesive designed for the cold lining of paintings.

CM Bond Liquid Hide Glue Cons Mat Ltd Freeport blvd.  Seprated but still liquid in a plastic bottle. Cons Mat Ltd (Marietta Way)1992

CM Bond M-4 less than a quart, separated, in plastic jar.  Cons Mat Ltd (Marietta Way)1992

CM Bond M-4 “vinyl acetate/ ethylene copolymer emulsion” Cons Mat Ltd (Kleppe Lane) Small plastic bottle, seems unopened? Circa 1993-95?

Emulsion pH = 4.0-6.5 (manufacturer). Dried film is soluble in methanol. Vinyl alcohol/ vinyl acetate copolymer? Flexible

CM Bond W-2 bookbinding adhesive  Still liquid Cons Mat Ltd 1 quart unopened. Cons Mat Ltd (Marietta Way) early1990’s

primarily composed of a polyvinyl acetate emulsion. CM Bond® W-2 contains small amounts of vinyl alcohol, soap, china clay and a phthalate plasticizer (Down et al 1996).

CM Bond W-1 Plastic bottle (25% full) separated, very old Cons Mat Ltd Freeport Blvd 1981

primarily composed of ethylene vinyl acetate. CM Bond® W-1 also contains small amounts of vinyl alcohol, soap and phthalate plasticizer (Down et al 1996).

Ethulose 400 ethylcellulose powder Plastic jar (50% full) very old

white powder composed of ethylhydroxyethylcellulose. Ethulose is a water soluble, nonionic cellulose ether. A 4% solution forms a thick viscous liquid while a 8% solution is a gel. Ethulose dries to a flexible matte film.  Non-ionic.  Has plasticizer dibutyl phthalate in it?

Fueki Rice Starch Paste September 1997  Kimura Framing & Gallery, Inc.1933 Ocean Avenue, San Francisco, CA  94127-2795 U.S.A. (650) 322-3984 bought 1997

Gluten-free, high quality paste made from polysaccharide granules separated from wheat flour to form a low viscosity solution when heated with water. 18% natural starch, 2.24% natural salt, 2.07% age-resister, 0.3% antiseptics, , 0.03% perfume.  Pre-mixed.

Golden Gel Matte Medium plastic jar 8oz.  2009

Some archaeologists and museums in Alaska use this for labeling artifacts, I was given some to test

Golden Self Leveling Clear Gel plastic 8oz jar and a glass brush bottle Feb 2010

Some archaeologists and museums in Alaska use this for labeling artifacts, I was given some to test

Isenglas 20g sheet Kremer-Pigmente in plastic bag  1992?

Has low surface tension and good wetting properties

Jade 403 PVA From Talas, 1 pint plastic jar.  Ellen’s circa 2005

white aqueous adhesive emulsion containing ethylene vinyl acetate (20/80) copolymer. Jade 403 may also contain small amounts of plasticizers, dispersion aids, defoamers and preservatives. Traces of formaldehyde have been found (Down et al 1996). pH 6.5-7.2  Dried film swells in water, ethanol

Lascaux 360HV 1 pint in lpastic jar from Talas 2010

Methyl methacrylate butyl acrylate thickened with acrylic butylester. The dry film is slightly tacky and can be used as a weak pressure sensitive adhesive or it can be activated to improve adhesion with toluene, alcohol or heat (50-55°C). The emulsion can be thinned with water, but once the film is dried it is insoluble in water. Lascaux 360 HV is used as an adhesive for lining paintings and textiles.

Lascaux 498 HV  from Talas. 1 pint plastic jar. Oct 2007

water-based emulsion containing butyl acrylate thickened with methacrylic acid (40% solids). Lascaux Acrylic Adhesive 498 HV can be thinned with water, but once the film is dried it is insoluble in water. The minimum film formation temperature for 498 HV is approximately 5C. A dry film is slightly tacky and can be used as a weak pressure sensitive adhesive or it can be activated to improve adhesion with toluene, alcohol or heat (75C). Lascaux Acrylic Adhesive 498 HV has been used for lining and mounting canvases, paper, wood and plaster.  pH is 9-10 but dies to a lower pH Tg 26C

Lascaux Medium for Consolidation 1 pint liquid in a plastic jug Aug 2009

aqueous dispersion of acrylic co-polymers based on acrylic ester, styrene, and methacrylate ester manufactured by Lascaux Colours and Restauro in Switzerland and available through Talas in the U.S.

 

Liquitex Matte Medium   in a plastic bottle.  Almost empty. 

May have been used by Mary Pat Wyatt in the 1980’s for basketry repair?

Methylcellulose One Quart plastic jar, powder, 1980’s or earlier

white powder that is used as a synthetic substitute for natural gums. It forms a highly viscous colloidal solution in cold water that reversibly gels when heated. Methyl cellulose dries to a clear film with very little shrinkage. It has been used as a substitute for gelatin and glue in sizing paper and has been used as an adhesive in textile and paper conservation (Kuhn 1986). Methyl cellulose has also been used as a poulticing material to pick up stains; as a poultice the addition of fumed silica minimizes depth penetration while the addition of glycerin adds flexibility. Methyl cellulose is sometimes found as a binder in pastels and watercolor paints. In industry, methyl cellulose is used as a lubricant, suspension aid and emulsifier. It is used in foods, leather tanning and cosmetics. Aging studies indicate that methyl cellulose (MC) polymers have very good stability with negligible discoloration or weight loss (Feller and Wilt 1990).

Methylcellulose in distilled water 5% July 2003 250mL glass lab jar (20% full, slightly cloudy)

Methylcellulose in smaller glass jar, liquid, no date Likely pre-2000

Milliput Epoxy Putty two rods in a cardboard box 2001

POLYOX WSRcoagulant 1lb in a plastic tub

Tested on PEG treated archaeological basketry.  Very stringy and mucous-like, poor handling properties, weak adhesive.  POLYOX® WSR coagulant is a non ionic polyethylene oxide with a molecular mass of 5,000,000 g/mol manufactured by Dow Chemical

PVA Polyvinyl acetate emulsion in large ½ gallon plastic jar from Light Impressions  and two smaller applicator bottles.  April 1999.

one of the most widely used water-dispersed resins. Polyvinyl acetate water-based emulsions have been used as latex house paints, artists’ media (since 1938), and common household white glues. Setting is accomplished by the removal of water due to evaporation or absorption into a substrate. PVAC resins produce clear, hard films that have good weather resistance and withstand water, grease, oil, and petroleum fuels. Additional properties are high initial tack, almost invisible bond line, softening at 30-45C, good biodegradation resistance, poor resistance to creep under load, and low cost. Polyvinyl acetate resins and copolymers are also used as hot-melt adhesives, sealants, fabric finishing, plastic wood, and inks  pH is acidic

Rabbit Skin Glue From Permanent Pigments.  Very old.  1/4lb paper jar with metal lid.  Yellow crystals. 1970’s or older?

Rhoplex N-580 liquid in plastic jar, less than ½ quart.  Cons Mat Ltd Marietta Way early 1990’s

Rhoplex® N-580 is composed of polybutyl acrylate. The emulsion has a solids content of 54-56% with a pH of 7.5-8.5. Rhoplex® N-580 dries to for a slightly tacky film that is used as a pressure sensitive adhesive.  pH starts at 9.6 but dries to 5.9?  Contains formaldehyde and ammonia. 

Sturgeon Glue (Hausenblase)  20g sheet Kremer-Pigmente in plastic bag  1992?

Wheat Starch Paste  (uncooked) as powder in a large plastic jar Cons Mat Ltd Freeport Blvd 1981

Wheat Starch Paste in a plastic bag, maybe from the big jar?

Wheat Starch Paste as powder in a baby food jar, labeled 1997, maybe from big jar?

Zen Crystals  from Archival Products LA.  Powder in a small plastic jar

Precooked wheat starch paste

Zin Shofu Conservation Materials Ltd (Marietta location) sample in ziplock bag  Early 1990’s

wheat starch with gluten removed by precipitation  treated to remove the insoluble glutamine in the starch. This produces a very smooth, water-soluble paste with a neutral pH. The flexible dry adhesive has been used for hinging photos and prints

 

SOLVENT-BASED:

Acryloid B-48N 45% solids in toluene 1quart metal container nearly full  Cons Mat Ltd (Freeport Blvd) 1980’s

Methylmethacrylate butyl acrylate copolymer w/ butyl phthalate plasticizer.  Bonds well to metal 

Acryloid B-67 dry beads in a paper bag from Talas. Old

Isobutyl methacrylate polymer w/ crosslinking inhibitor.  Yellows with age.  Soluble in mineral spirits, acetone, isopropanol, etc Used mostly as a varnish?

Acryloid B-72 in plastic squeeze bottle, very thick c.2006?

Acryloid B-72 in a small glass brush bottle marked “toss” (50% full)

Acryloid B-72 in a brown glass bottle from Cons Emporium Aug 2002 full

Acryloid B-72 10% in ethanol in glass jar Jan 2010

Acryloid B-72 in acetone 5% Feb 2005 500mL glass lab jar (30% full)

Acryloid B-72 in acetone June 2001 500mL glass lab jar (30%)

Acryloid B-72 in acetone/ ethanol 5% Nov 2001 250mL glass lab jar (10% full)

Acryloid B-72 in xylene tall commercial glass jar (20% full)

Acryloid B-72 in 3 tubes from HMG, one full, one nearly empty, one used Aug 2002

Acryloid B-72 in three metal tubes from Steve Koob, Ellen’s from 1999

Acryloid B-72 in tiny vial with glass microballoons, hardened.  Ellen’s circa 1999

Araldite AY103 epoxy Cons Mat Ltd  125g glass bottle unopened? Freeport Blvd on label, circa 1980’s

Digycidyl ether of bisphenol A

Araldite Hardener HY956 Cons Mat Ltd 25g glass bottle unopened? Freeport Blvd on label, circa 1980’s

Mixed aminopoly (ethyleneamine)  Araldite is tacky for an hour, takes 24 hours to cure.

BEVA solution 371 in 1 gallon metal can mostly full Cons Mat Ltd (Marietta Way)1992

composed of Elvax (ethylene vinyl acetate [EVA] copolymer), Ketone Resin N (polycyclohexanone), A-C copolymer (EVA), Cellolyn 21 (phthalate ester of hydroabietyl alcohol) and paraffin. BEVA® 371 is an opaque gel at room temperature that produces a matte, waxy finish. It has been used for relining paintings and as a consolidant for paintings, leather and textiles.

BEVA finishing varnish sample  Cons Mat Ltd in a brown glass jar

CAMEO reports this as a transparent synthetic varnishes primarily of cyclohexanone resin. BEVA® varnishes are available in glossy, matte and UV stabilized formulations. The matte varnish contains wax as a matting agent.

BEVA 371 film on a roll Cons Mat Ltd (Marietta Way)1992

Butvar B-98 white crystals in a plastic jar, from Monsanto.  Very old pre-1981.

used commercially as adhesives, sealants, inks, and coatings to waterproof textiles and wood.

Butvar B-98 10% in ethanol 5% from 1981 large glass jar still clear liquid

Butvar B-98 in ethanol 5% from 1981 in small glass jar, dried and yellowed

Butvar (polyvinyl butyral resin) dries matte but over time becomes insoluble in acetone

ConServ Epoxy part B 500mL glass lab jar full (very yellow) 1998

ConServ Epoxy Part A 500-2 Epoxy Resin 1 Q metal can full? 1998 DISCARDED 2010 (dried up)

ConServ Epoxy Part B 500-2  Curing Agent 1 Q metal can full? 1998 DISCARDED 2010 (dried up)

Wood, metal, masonry, rebar structural repair

ConServ Epoxy Part A 100-1 Epoxy Resins 1 gallon metal can half full 1998

ConServ Epoxy Part A 100-1 Epoxy Resins 1 gallon metal can full 1998

Soft and decayed wood, nonstructural, flexible

Devcon Super Glue II in a tiny metal tube 2009

Not used on artifacts.  Used to make armatures or repair lab tools

Duco Cement two small metal squeeze tubes

Cellulose nitrate adhesive no longer recommended for use on artifacts. Used at ASM for scale casts of hair on microscope slides.

Epoxy Wood Consolidant part A Aug 2002 large glass jar (80% full) 2002

Epoxy Wood Consolidant part B medium glass jar full 2002

Hxtal Epoxy part A medium glass jar  (30% full)

Hxtal Epoxy part B medium glass jar  (10% full)

two-part epoxy adhesive made with the diglycidyl ether of bisphenol A and triethylene diamine. Hxtal NYL-1 is a low viscosity, colorless, transparent resin that hardens to form a clear strong bond. It has been used for glass and china repair. Hxtal may discolor in direct sunlight  Refractive index 1.51

JB Weld Kwik Two metal tubes, 2009

Two-part epoxy with some filler in it, never used on artifacts here, only used to make armatures or repair lab tools.

Klucel G From Talas, 1/4lb bag of powder.  2009

Tested for scale casting fur and also for consolidation of PEG treated basketry, not so good for either one.

Klucel G 2% in ethanol 2009

Klucel G 20% in ethanol 2009

Klucel GF Conservation Materials Ltd (Marietta location) sample in ziplock bag Cons Mat Ltd (Marietta Way)1992

Described in Cons Mat Ltd catalog as flexible, not tacky, and a good barrier to fatty or oily materials.

Klucel from Cons Mat Ltd in a plastic jar, solidified. Marietta Way, early 1990’s

hydroxypropyl cellulose (HPC) compounds. Klucel® polymers are nonionic, water soluble, ethers of cellulose.  Leather consolidant?  Not very strong.  Can pre-saturate lifing flakes before use of methylcellulose to prevent discoloration.  Usually dissolved in ethanol. 

No longer manufactured?

prepared by kneading equal portions of each stick together until mixed. Milliput® shapes readily; surface drying can be minimized with a few drops of water. Before it hardens, acetone can be used for smoothing. The putty sets in 1 hour and hardens in 2-3 hours. Once hard, Milliput® can be sanded, drilled, cut, or filed. It adheres to wood, metal, plastic, glass, and porcelain. Milliput® is available in pure white, yellow-green, gray, and terracotta colors and may be tinted during mixing or painted after drying.

When hardened, Milliput is resistant to water as well as most solvents and chemicals

LMW Resin Top Coat 20% in low aromatic content solvent from Conservation Support System in 2009

Used in some museums as a top coat for applying labels to artifacts, given to the lab for testing.

Paraloid F-10 supplied as 40% in mineral spirits, one quart metal can June 2010

n-butyl methacrylate homopolymer. Softer and more flexible that Paraloid® B-72. Used as a heat sealing adhesive. When used for nap-bonding of net support, it adheres to the surface of the textile rather than penetrating (Lewis 1983) as mentioned on MFA’s CAMEO.

Paraloid B-67 1 kg bag of plastic beads MuseuM Services Corporation June 2010

Isobutyl methacrylate polymer. It contains a crosslinking inhibitor,yellows slightly with ages.  Soluble in toluene, xylene, methylene chloride, ethyl acetate, mineral spirits, VM&P naphtha, acetone, methyl ethyl ketone, isopropanol.

Paraloid B-72 from Conservation Resources in small plastic bucket.  Dry beads.

PC-11 marine power white epoxy paste A in small metal tin

PC-11 marine power white epoxy paste B in small metal tin

Scott used on giant ceramics from an artist who used them

PVA AYAA Labels says Cons Mat Ltd Freeport Solid chunk in original plastic jar, clear. Small ziplock of dry beads Invoice says Cons Mat Ltd (Marietta Way)1992

low-molecular weight thermoplastic polyvinyl acetate resin. AYAA has an average molecular weight of about 83,000. It does not contain any additives. AYAA is colorless initially but yellows with light aging (Down et al. 1996). It is often used as a hot melt adhesive where its minimum heat seal temperature is 60 C for 1.5 seconds  May release ethyl acetate, ethanol, water, acetaldehyde on aging

PVA AYAC Cons Mat Ltd Freeport Dry beads in original plastic jar, clear. Cons Mat Ltd (Marietta Way)1992

It is generally used as an additive in other polyvinyl acetate resins to lower their softening point.  May release acetic acid on aging

PVA AYAC solidified in glass peanut butter jar, clear

PVA AYAF Cons Mat Ltd Freeport Dry beads in original plastic jar, clear. Cons Mat Ltd (Marietta Way)1992

PVA AYAF in xylene March 1980 tall glass jar (30% full, still viscous)

AYAF was previously sold as Vinylite A

PVA AYAF 40% in 1:1 acetone: ethanol in a glass jar 2009

PVA AYAT Cons Mat Ltd Freeport Dry beads in original plastic jar, clear  Dry beads in ziplock bag  Cons Mat Ltd (Marietta Way)1992

European equivalent is Mowilith 60; Vinylite (former name)

PVA AYAT 20% in acetone in a glass jar 2009

PVA AYAT 10% in acetone in a glass jar 2010

PVA Marking Varnish in a 1 pint glass jar from MuseuM Services Corp 2010

Bought for artifact label testing. 15% AYAF PVA in alcohol.

Regalrez 1kg bag of plastic pellets from MuseuM Services Corp June 2010

Low molecular weight hydrocarbon resin. Regalrez® 1094 is a hydrogenated oligomer of styrene and alpha-methyl styrene. Soluble in petroleum distillates. Most often used as a synthetic LMW resin to re-saturate dull ptg varnishes.

Sally Hansen Hard as Nails small commercial brush bottle

Wide range of ingredients in solvent, tested for scale casting fur and not as good as Duco.  Never used on artifacts.

Soluvar Matte Varnish from Liquitex  large plastic bottle 2010

Bought for testing artifact labeling. Includes 2-(hydroxyl-di-amyphenyl) benzotriazole acrylate monomers, petroleum distillates.  Soluvar® varnishes are designed for use on polymer (e.g., acrylic, vinyl), casein, and tempera paintings according to the CAMEO website.

 

WOAM 2010 in Greenville May 28

ANALYSIS AND CONSERVATION OF LEATHER, BONE, AND OTHER ORGANIC MATERIALS

A New Approach to Excavating and Handling Waterlogged Textiles from the American Civil War Submarine the H.L. Hunley. (peer reviewed)

Johanna Rivera and Philippe de Vivies

The Hunley was the worlds’ first successful submarine, sunk in 1984 and found in 1995.  Over 1,400 artifacts have been recovered steadily since 2005, including textiles and organics (wood, leather, rope, horn).  The inside of the submarine was completely filled with sediment.  All crew were found at their stations.  The talk involved the textiles on Lt George Dixon, removed in 7 block lifts.  The block is placed in a tank and then slowly filled with water.  A syringe filled with water is used to dislodge the sediment.  Sediments are vacuumed off with a siphon hose made of PVC plastic, controlled by pinching with the fingers.  When the need comes to flip it, they fill in gaps with foam, then cover all with a thin plastic film, and then fiberglass (DuraPower Inc Pipe and Hose Repair Kit) and then polyurethane resin.  When firm, then they can slide something underneath and flip, exposing the other side for cleaning.  Four fabrics were found: a fine black or brown wool, a cotton/wool, a red that turned brown with exposure to UV light, and a strange thread that was all that remained of suspenders that were apparently made of natural latex rubber.  Fragments of textile were unfolded underwater, and rounded Mylar patches helped with the manipulation.  One textile was a vest, but its stitches that held in the lining were only on the surface, no longer penetrating through the cloth.  There is an entire AIC presentation on the vest treatment.  Use of a surfactant helped remove dirt from the textile and keep it in solution instead of re-depositing on the textile.  There are five more blocks from Dixon to be dealt with, and another 27 textile blocks from the rest of the ship, a huge undertaking.  Elizabeth Peacock asks about dye analysis, and says its not likely to be madder, for example, as madder dyed textiles are often better preserved than other textiles in the burial environment. 

A Neolithic Shoe from Sipplingen Conservation and Technological Examination

Ingrid Wiesner

The shoe was found in a burned layer, and thought to be 5000 years old.  The material seems to be strips of retted bast fiber, from the lime tree (tilia?)  Comparisons were made to other old shoes that had been treated: Feldtkeller (1989) used PEG 400, and consolidated with Luviskol K30 after and then Bojesen-Koefoed et al (1993) using high molecular weight PEG.  Seems that for this Sipplingen shoe, 8% PEG 1500 followed by freeze drying was the way to go.  Another example about how the conservation field is moving away from the use of low molecular weight PEGs.

Analysis of Plant Fiber Artifacts from a Shipwreck: Application of Material History Methodology

Runying Chen

Dr. Chen had a cool chart that was looking at Observation Data, Complementary Data, Supplementary Data, and then Conclusions along the rows, and then the columns were looking at Material, Construction, Function, Provincial, and Value.  This was Smith’s Material History Methodology from 1985.  Fits nicely with conservation treatment report format, doesn’t it?  Dr. Chen was saying it really helps you to be more disciplined and eliminates pre-conceived notions or bias by using a matrix like this.  There’s a recent article in the Journal of Nautical Archaeology that is a cordage study (French?) and has a new recommended framework for how to describe cordage.  It is tricky to compare cordage if people are not talking about it in the same way.  Louis Bartos is a sail maker and historian who was a useful resource.  Info about the plant fibers can give you an idea about the size of a ship and the kind of sails it has…looking at the angle of twist, type of weave, seam construction, stitching, etc.  I think Dr. Chen felt a little out of place in the context of the other papers, but I thought this was really valuable.  With our noses so deep in the science, it is nice to be reminded of the balance we need to have with the interpretation of our wet organics and not just the preservation of our wet organics.  Conservators are often called upon to help interpret what we are seeing and it is great to be reminded of some of the work that is happening in that area too.  And knowing what people need to look at for interpretation helps guide the aspects of what we need to prioritize for preservation.

 

Polyethylene Glycol Treatments for Basketry on the Northwest Coast of North America (peer reviewed)

Ellen Carrlee and Dana K. Senge

This was our talk, and I was so glad it was on Friday so I had a chance to ask a lot of people about it before getting up in front of everyone.  Despite feeling a little out of our element, Dana and I were definitely on the right track.  We were trying to come up with a PEG protocol that would work for basketry.  I had two baskets in the lab already treated with 20% PEG 400 and 5% PEG 4000, based on the best knowledge from the late 1990’s, and even though they looked nice, they were too fragile.  So I wanted to see if using high molecular weight PEG would help, maybe without low molecular weight, and maybe at higher concentrations.  I think that panned out, and is in harmony with the current understanding.  Also, my consolidation with Butvar B-98 seems to be something others have found useful.  Maybe 55% PEG 3350 is a good way to deal with very deteriorated spruce root.  And maybe basketry treatment, which has been very challenging for lots of people, might be best approached with a two-step treatment: step one being PEG and step two being consolidation.  I did not get an answer about why my unheated sample treated with 20% PEG 400 and 75 PEG 3350 turned very dark on cycling RH but the heated sample did not get dark.  In all cases of treatment with 75%, that was too high and they were excessively brittle.  at Dana’s work in compiling old basketry treatment info is right on the money as well, as this kind of data is really useful and she was right to start capturing that, too.  We are still missing a bit of the degree of deterioration problem, since Dana and I struggled with what we were seeing under the microscope.  I now have this fantasy that I can attract a grad student in wood anatomy to come from Minnesota and work up spruce root and cedar bark for me.  If we cover those two materials, we’ve covered most of the baskets on the Northwest Coast?  Carlos is keen to try silicone oil on the problem, and maybe I will collaborate with him a bit on that.  I have to think it through, since I am feeling like I have a good direction to go with these treatments using techniques that I am comfortable with in terms of reversibility/retreatability, but the idea that giving over a bit of this material for silicone oil might add to our overall big picture knowledge of various tools in our toolbox…hmmm.  Tara Grant agreed that POLYOX wasn’t that useful, but in order to work with it they found that putting a pool of it on the table and pushing to object into it was a good way to deal with its lousy handling properties.  Kate Singley reports she’s had good luck with Lascaux, although the kinds I tried didn’t work so well for me.  Rope gives a similar problem, and was reported on at the Portland WOAM.  In Denmark, they tried using Paraloid F-10 on brittle rope after it was PEG treated and that worked well for them.  For the consolidation issue, I guess it matters quite a bit whether your consolidant is dealing with the PEG or dealing with the wood.  I suspect that if it is the former, then solvent-based consolidants are going to be good (as I was finding) but for the latter when wood is available for bonding (perhaps if the PEG has been cleaned off the surface) maybe that is when people are getting better results with the water-based consolidants.  And one final revelation, Dana points out that historical spruce root baskets are BRITTLE too!  Chemist Mikkel Christensen from Norway points out to me during one of the breaks that a general rule of thumb is that you can have stability or you can have flexibility but you cannot have both. Don’t miss Dana’s weblog of past basketry treatments and their outcomes at http://waterloggedbasketry.blogspot.com

Assessing the Physical Condition of Waterlogged Archaeological Leather (peer reviewed)

Katerina Malea, Thelxiopi Vogiatzi, David E. Watkinson

To ID the animal species, they used SEM to look at the hair follicle pattern.  To assess degree of deterioration they were looking at amino acid analysis of the collagen.  In examining leather visually, people tend not to agree in how deteriorated they think it is.  pH reflects degree of hydrolytic deterioration.  In the 4.6-7.5 range, with most in 5-7 range.  They were also looking at shrinkage temperature, and how broad the range was from when the first one went to the last one in heating for shrinkage.  Looking at ratio of basic:acidic amino acids?  If the ration is low, does that indicate oxidative deterioration?  I am not quite catching all the science, it is a little above my head on this talk.  Some commentary afterwards cautioned the use of shrinkage temperature as a tool, since it was designed for use on recent leather.  Apparently, there’s been some difficulty using it on archaeological leather because of mineralization?  It behaves unpredictably?  There was a 1997 study that showed a correlation between mineral content and shrinkage temperature.  The plot thickens!!

A Comparative Study of Various Impregnation and Drying Methods for Waterlogged Archaeological Leather

Angela Karsten, Kelly Domoney, Liz Goodman, and Helen Ganiaris

There’s a backlog of leather to be treated in the UK, which is a problem because it is prone to mold growth, analysis cannot be completed until it is dry, and it cannot go into a repository wet.  Usually, leather from anaerobic terrestrial sites is pre treated with glycerol or PEG and then freeze dried.  20% glycerol gave the best results, and EDTA along with it was good and also helped with flexibility.  Using that in conjunction with vacuum freeze drying was the best, and air drying was OK too.  All treatments dried darker and somewhat brittle, although the freeze dried ones were easier to examine without damage.  The ones that went through controlled air drying with a series of salts to control RH had challenges with mold and using the technique was a pain.  If they got some pre-treatment, even 10 years in storage was OK and they didn’t get moldy and good results were still possible.  However, without pre treatment they tended to curl up.  Ian Godfrey reports that in Australia, they found the glycerol treatments caused dessication and brittleness over time.  In the UK, however, it seems that they’ve been using it since the 80’s without that issue, although that’s anecdotal and maybe it needs to be looked into.  Dr Godfrey is keen to assist in the analysis of leather and help distribute the results.  I think this issue of glycerol is really interesting.  Like how the glycerol in the alum treatments for wood seemed to make them much worse?  What is up with glycerol?  I want to understand it better.  Jim Spriggs says they treated leather in York with glycerol and freeze drying since the 1970’s and it does change over time.  The ones in York that came out the best were some weird combo of solvent dehydration and then a solvent soluble oil?  Wow.

Efficiency and Quality in a Batch Treatment: the Conservation of Over A Hundred Leather Shoes and Fragments

Jessica LaFrance

Metal cistern from 1850-1870 contained lots of leather shoes.  Used an ultrasonic dental scaler to clean.  Removed chlorides in tapwater baths, agitated, up to 3 months long.  Iron was removed with either 2% dibasic ammonium citrate as a batch of 50 (immersing them twice) or 5% sodium dithionite in 2% EDA (did I write that down correctly?) used on shoes individually.  The latter worked better, but cost more, took longer to prepare, and required ventilation.  Iron stains might have helped preserve the collagen?  The monitored the color of the solution to know when it was done.  When it was rinsing clear, then they treated the leather with PEG, 20% with 1% Hostacor IT since there were metal attachments and wood inserts inside the shoes.  She reshaped with foam supports and Supercrinx stretchy self-adhering bandages, and freeze dried for 2 weeks.  There was 7-10% shrinkage, and really maybe even a little more than that since they likely shunk a bit in transit.  After freeze drying, used some 2% Klucel G in ethanol where needed, and used Lascaux 50:50 498HV to 360HV applied by brush to sheets of Reemay and reactivated with acetone for tear repair. Susanne Grieve mentioned that the Hunley shoes were preserved with commercial shoe inserts successfully.  She also likes a material called Bibac plastic, which can be shaped with a hairdryer.  Sounds like it has lots of holes in it, so there is less surface area and the leather dries better?  Susanne likes Teflon tape during PEG treatment because organic bandages like traditional roller gauze has gotten moldy or has left marks on the surface of artifacts.  Emily Williams jumps into the issue of how the term “batch treatment” affects the concept of the artifact value to curators and collection managers.  Objects treated individually are perceived as being more precious.  But is it chicken and egg?  Have the curators and collections managers already made that judgment before the batch treating happened?  In the UK at least, with the volume of material and the limits on resources available to deal with it, there is a risk that things might get discarded rather than treated if batch treatment was not an option.  With some 35 years of experience, Elizabeth Peacock wisely says we don’t have to advertise that batch treatment is how it is done!

Conservation of Thule Skin Clothing from the Sannirajaq Site, Nunavut

Tara Grant

For me, this was maybe the most exciting talk of the conference.  Tara does archaeological fieldwork as well as conservation work in the CCI lab.  A 2006-2007 excavation of houses from 100-1400AD brought up boots, belts, fur parkas, bird skin inner parkas, gutskin anoraks, pants etc as well as human remains of 8 individuals.  After consultation, it was determined to rebury the human remains, and the clothing was excavated separately.  There were health problems and strong odors to be dealt with.  The precendent of Christchurch, Spitalfelds, England was useful.  It seem that lead dust, mold, and parasite eggs are a bigger risk than infectious disease.  Anthrax and smallpox can survive, but plague, cholera, typhoid and tuberculosis do not tend to survive in burial.  The site was pre-European contact and there were no domesticated animals.  The Canadian Science Center for Human and Animal Health was also helpful, and determined that with appropriate personal protective equipment, the staff would be OK.  They used a HEPA unit and charcoal filter for odors, mostly from putrescine and cadaverine.  These are water soluble compounds that smell even more in high RH conditions.  Mary Ballard’s work on this was very helpful.  20g/L water of sodium bicarbonate for proteins and sodium carbonate for cellulosics.  The objects she was talking about were mainly a parka with seal fur, caribou fur and birdskins with the feathers still on them.  (Cool tidbit, diving birds have stronger skins!)  There were also boots of defurred seal skin.  Gutskin anorak.  They were dealing with hair loss, slippage, dirt, fat, loose/open seams, rips/holes in the skin.  Some of the loss or damage was from pre-burial, as evidenced by things like a knot tied in the gutskin near a loss.  Tara had really cool slides about gutskin structure.  Summer gut is dried in above-freezing temperatures and is not as flexible as winter tanned gut which is dried at below freezing temperatures.  They were looking at shrinkage temperature, which as between 45 and 63 for the artifacts, and modern seal and cow are 55C and 60C respectively.  There’s a new technique for measuring Ts which is more accurate than the old visual method, so the reference numbers are a little different these days.  So on the anorak, for example… They were using 20g/L of sodium bicarbonate, and is thought to preferentially react with amine rather than protein. 30 minutes, agitate, pH of 8 (a little high for skins) and then sodium dodecyl sulphase 0.5w/v as an anionic detergent to remove fats.  Brush and cavitron cleaning, then a 17 hour rinse with running water to remove detergent.  Repeated detergent and deodorizing, then rinsed for 4 days.  They used 20%v/v PEG 400 for 24 hours, and the rinse, tamp, reshape, freeze at -22C.  Odor removal was only partly successful.  Feathers especially still had some smell, but seams were loosening and feathers were starting to detach so things had to stop.  AT the gut didn’t smell at all, and they were able to use a cold mister and finger pressure to manipulate and then clamp into the desired shape. 

Conservation of Waterlogged Ivory

Ian Godfrey and C. Wayne Smith

This particular talk was dedicated to the late Sophie Lussier, who did some important work on testing materials to use with ivory.  Elephant tusks were found in a 1970’s excavation of a Dutch shipwreck.  Tusks form as a cone-in-cone structure.  Tendency to delaminate.  No relationship between deterioration of ivory and success of treatment options.  Some tusks had been “looted” pre-ban and air dried OK, others did not air dry OK.  Layer of corrosion products on the outer surfaces were iron rich, and then there was an inorganic matrix better preserved at the core.  Calcium would be replaced by iron, and you’d see that lovely blue vivianite.  FTIR was the most helpful tool, it is really good for bone and ivory.   There was collagen in the rich outer layers, but not in the core.  Texture of the ivory was different throughout as well, with some areas as soft as paste and others very hard.  Form 1996-99 they tested Rhoplex AC-235 30% for 4 months, Primal MV-23-LO 30% for 4 months, Gelatine 30% at 30-40C for 4 months, Biodur S-10 with S3 hardener and S6 gas cure (plastination) and finally silicone oil (SFD-10 silicone oil with MTMS crosslinker and the dibutyltindiacetate catalyst.)  The aqueous treatments were all slow dried over 15 months.  The Rhoplex penetrated only 1mm in.  Aqueous stuff didn’t really work so well.  Really, only the plastination and the silicone oil treatments worked.  To do the silicone oil, they bound the tusk so it would not fall into pieces during treatment.  For the plastination, they probably ought to have done it at -30C in acetone, but it was done at room temperature in the hopes it would remain more fluid and penetrate better, and so the results maybe not as good as they could have been.  They embedded the tusk samples in epoxy and polished it down to look in SEM and see where the material went.  There was lots of silicone oil in area with heavy degradation, and then a steady amount in other areas.  By making a mixed sample with non-silicone treated ivory, they were able to prove they were not just smearing silicone around during polishing.  People were wondering after the talk if the silicone oil treatment would inhibit the oxidation of the pyrite.  Looked from this talk like silicone oil might be an appropriate tool for treating this tusk material since there wasn’t really anything else that worked.  At the end of his talk, Ian Godfrey brought down the house with killer images of live “flying” penguins from his work in Antarctica.  Is it an accident his talk was last?  Or was he intentionally chosen as the closer?

Check out additional posts on the business meeting, specific WOAM personalities, the flavor of WOAM, and Lars Andersen’s advice to me on freeze drying at the AIC’s news blog.

WOAM 2010 in Greenville May 27

SULFUR, IRON, ALUM, AND OTHER INORGANICS IN WOOD

Vasa—Recent Preservation Research

Lars Ivar Elding

The Swedish warship the Vasa sunk in 1628 and was recovered in 1961.  It is 900 tons, 60 meters long, full timbered with a 40-50cm hull and had 20,000 objects on it.  Since it was found, it has taken 50 tons and PEG and 15 tons of borates to preserve it, and maybe 5-10% of its current mass is PEG.  The 200kg pentachlorophenol it was treated with as a biocide has decayed over time and is no longer observable.  It went from having 150% water content down to only 10% today.  The ship gets some 1.1 million visitors every year.  In the 1990’s salt precipitates were discovered, made from sulfate salts reacting with the iron, causing an internal formation of sulfuric acid.   This was the subject of a 2002 paper in Nature, but now we know this was just one of several reactions and the situation is rather complicated.  From 2003-2006, the “Preserve the Vasa” project aimed to answer some questions: What was the microbial activity? (negligible) How about sulfur-iron chemistry?  Removal of the iron catalyst (EDHMA and DPTA dunno if I got those acronyms right though) PEG stability (formic acid found but decay in practice was negligible) Influence on the wood?  (Yet to be determined) The next phase, the 2008-2011 “Future for the Vasa” project, asks, Which processes are important? How extensive? How fast? How is the wood effected?  Lot of oxygen and a pH 4 is needed to keep reactions going.  There are low pH values deep in the timbers, so perhaps reactions are going on there?  The surface layer is weak and degraded, then there is an area which is rich in iron 3+ and then deep inside there is iron 2+.  Somehow, a high concentration of sulfur inhibits iron-dependent degradation.  Cellulose hydrolysis caused by sulfur is an over-simplification.  Because of all the visitors, they are limited in the kinds of techniques they can use.  In 2004, a new climate system was installed.  RH 55% and temp 20C.  Iron bolts are being changed out for carbon fiber or stainless steel.  The ammonia gas that might help only has 1-2cm penetration, look for a 2010 Studies in Conservation article about it.  Right now, we ought to take a sample and store it at low temperature and  low pressure and look for change over time.  Wish we had samples from 10 years ago, even though it does not look like there have been major changes in that time, who knows?

Iron Removal from Waterlogged Wood and the Effects on Wood Chemistry

Vicki Richards, Ian Godfrey, and Kale Kasi

Recovery in 1985 of an iron steam engine from the 1872 wreck of the SS Xanthro, had electrolysis in sodium hydroxide for years.  In 1994, the baseplate was removed and there were some 100 wood chocks under there, coated in tallow (a lubricant for the engine.)  From 1991-93 they treated them with dithionite and citrate and PEG 400 to preserve them and remove the iron.  Took some 20 days for the iron to start coming out, and it seemed to come out best with dithionite.  The solution got pretty acidic, below 3.  They tried diethylentriamine penta acetic acid, but it wasn’t as good.  Tallow interfered with the FTIR peaks when they tried to look at effects of chelating agents on the deterioration of the wood.  I have to admit, I didn’t understand this chemistry very well due to my own lack of background.

Nuclear Magnetic Resonance and Fourier Transform Infra-red Spectroscopic Analyses of Acid-Affected Waterlogged Archaeological Wood

Ian Godfrey, Vicki Richards, Lindsay Byrne, and Emil Ghisalberti

Trying to look at degradation of Vasa to reference wrecks still on the seabed to see what kind of deterioration happens after treatment compared to doing nothing and leaving it in situ.  Had to have big samples, 200mg, so there is sample left for other kinds of work also.  Seems like there was more cellulose loss from the Vasa, and the inner part has lost more than the outer part.  Perhaps areas that have more formic acid, like the outer areas, indicate more PEG since formic acid is a degradation product?   There was more acetic acid on the inner parts.  Truth is, there is more PEG degradation in the inner core even though there was more formic acid on the exterior.    This is another talk where I could not follow all the science very well, a little above my head.  I actually wrote in my notes at one point, “Big ol’ brain on Ian!”

The De-Acidification of Waterlogged Archaeological Mary Rose Timbers with Strontium Carbonate Nanoparticles.

Eleanor Schofield

The Mary Rose was the flagship of Henry VIII, dating to 1545.  About half survived in silt and was recovered in 1982.  Hoping to have money to rehouse it in 2012.  There are some 19,000 artifacts as well, and they have a sulfur problem.  They are using XANES (xray absorption near-edge structure spectroscopy) to see different oxidation states and distinguish between the sulfate compounds.  Before, sulfur was “spectroscopically silent.” SrCO3 good because strontium was a better marker when used at .005 molar, and it became associated with sulfur in the wood.  Forms SrSO4?  Stronium sulfate as an insoluble material, something more stable to leave in the wood?.  Gosh, this was pretty beyond my ability to grasp as well.  These heavy-science talks exceed my science knowledge, so I can’t interpret them very well.  Sorry about that.

Extraction of Sulfur Compounds from Archaeological Wood by Chemical Oxidation with Sodium Persulfate

Khoi Tran, Fanny Bauchaud and Clement Werner

Trying sodium persulfate to chemically oxidize the iron sulfides, 13.5% worked the best.  Buffered the acidic solution with sodium hydrogenocarbonate NaHCO3.  On the LaLomilla wreck, they were finding 80% pyrite, 20% silica and pyrite accretions, with 17% ash on the surface and 7% inside of the plank.  5 baths needed to soften accretion so it could be mechanically removed with a brush.  Only about 10g removed from a 6kg plank?  The PEG treated and freeze dried.  There were still minerals in there and PEG could not fully penetrate, so there was some shrinkage.  Also tried to do a poultice application on the crusts that came out after the PEG treatment.  Cellulose pulp, .14M sodium persulfate, and 0.05 sodium bicarbonate buffer.  10 months later, they still have pyrite but look OK with no effluorescence.  Maybe try electrophoresis in a poultice for in-depth extraction of ionic compounds? That has worked in the past to extract alum from wood. 

Re-Conservation of Wood from the Seventeeth Century Swedish Warship the Vasa with Alkoxysilanes: A Retreatment Pilot Study Applying Thermosetting Elastomers

Carlos Cabrera Tejedor

In my notes at this point, I have written the remark, “OMG, I am the least illustrious person in this room!”  Carlos was using Xiameter PMX-200 silicone fluid CAS # 70131-67-8, Dow Corning SDF-1 (about 75CST viscosity, ranges from 55-90) and the MTMS brand name Xiameter OFS-6070 silane CAS# 1185-55-3 as the crosslinker.  Carlos was looking at color using a Munsell color chart, texture, dimensional change, weight, volume variation and microscopic features.  His first test was to immerse the Vasa sample in MTMS at 70C to extract PEG over about 20 days, dry it, and catalyze the MTMS.  Was a little waxy, heavier, and maybe they could not get out the PEG enough?  Second test was soaking PEG out with deionized water, progressive removal of the water with ethanol and then to acetone in 25% increments, impregnating with a little vacuum to help get all the acetone out, cleaning, and then catalysis with DBTDA.  The evaluation was OK, except for the volume variation and the microscopic qualities.  However, in the third test he removed the PEG in water only, not just in one step with MTMS, and the results were much better.  A gallon of silicone oil is $160, and a pint of MTMS is $75.  So if I understand right, the alternate MTMS treatment is better than either the traditional one or the standard silicone oil treatment when re-treating PEGged wood from the Vasa.  PROS: short time to do it, not too complicated to perform, and means that minimum preventive conservation would be needed to curate the wood.  Thin layer of agent (a few microns) allows much of the woody quality to be retained and the morphological features to still be easily observed.  Treated wood is hydrophobic, chemically inert, resists acids and bases, and resists change with UV light.  CONS include non-reversible, non-re-treatable (only repeatable with same chemicals), price of reagents, and the health and fire hazard. 

I have to say I spent a lot of time talking with Carlos during the conference, and liked him very much.  He was personable, candid, competent, curious, enthusiastic and open-minded.  Before Carlos, silicone oil was firmly in the “do not trust it” pile of treatment options that I had no intention of considering.  Now that I have spent some time with Carlos, I feel like I have a much better understanding of the silicone oil issue.  For example, I had recently heard that while it is NOT reversible, it is “retreatable.”  Indeed, this term “retreatable” has gotten a lot of traction in the conservation world now, admitting that we are not ever going to get everything back out again safely, so “reversible” is in our the theoretical standards and ethics while “retreatable” is kind of the real-world version.  However, in chatting about it, Carlos now plans to use the word “REPEATABLE” with silicone oil treatment, because in fact you do not have any other retreatment options with other materials.  You can only repeat the original treatment to try to get better results.  And Carlos was very candid in saying that when you get good results from the silicone oil treatment, they are really beautiful.  To hear him talk, the results are almost seductively, unbelievably beautiful.  Only the trained hand could really say, “hmmm, this surface is maybe a little too silky…not quite exactly natural but damn close.” (my own quote) But when it goes bad, it goes really really bad and there is no way back.  Carlos’s term, “It is like a bulldozer.”  And then there is the issue of the lab where all the LaBelle items are being done.  Time will tell, but if the treatments hold up, that will be lovely, and if they don’t… well, the vast majority of all the organics from that ship, thousands and thousands of artifacts, have been treated since 1998 with this material.  When you have a hammer does everything look like a nail? 

Possible Uses of the Calcium Complex of EDTA to Remove Iron

Mags Felter and Anthony Crawshaw

Mammoth tusk needed iron removed in order to improve aesthetics, reduce risk of acidification and reduce risk of oxidation.  Godfrey’s 2002 article showed that EDTA or diammonium citrate on bone or ivory strips the calcium and demineralizes the substrate.  If you stir in calcium hydroxide to a 1.1molar strength, you can do a treatment for up to 40 days that works better.  The problem was that good iron removing chelating agents pulled out Ca because the calcium complex is less stable than the iron complex.  Adding in calcium helps. 

The Use of an Electric Field for the Removal of Alum from Treated Wooden Objects

Iben V. Christensen, Lisbeth M. Ottosen, Poul Jensen, Inger Bojesen-Koefoed, Hartmut Kutzke, Mikkel Christensen, and Tom Sandstrom

Alum was used extensively in the Scandanavian countries for waterlogged wood until 1960’s.  Examples: Hjortspring, Oseberg, and Arby.  Alum did not penetrate very deeply, so inner part of the object often left unimpregnated.  Internal cracking happens.  Alum makes wood heavy and brittle, but not stronger.  This experiment put kaolin clay poultices on both ends of the wood with electrodes in the clay so you would not have to put screws in the wood.  Trying to make the potassium and aluminum go to the cathode (has citric acid there) and the sulfate to go to the anode (has CaCO3 there.)  Have to soak it in water so that the ions can migrate? No, but RH needs to be around 90%.  Took 3-4 days, at 4V and 3-5mA current.  There was no significant removal of aluminum, but there was good removal of the sulfate and the potassium.  Problems: possible electrode reactions, humidity needed,  risk of unexpected migration of ions, and that the removal was incomplete, maybe 70-80%.  If I understand correctly, the typical method for retreating objects treated with alum is prolonged soaking in water, and maybe this is hard on the delicate degraded objects, so coming up with a method like this where you didn’t have to submerge the artifact would be an improvement?

Past Conservation Treatments and their Consequences: the Oseberg Find as a Case Study (peer reviewed)

Susan Braovac and Hartmut Kutzke

The Oseberg sleds date from 834AD and were excavated in 1904, treated with alum sometime before 1914, and are unstable now…weak and very acidic (pH of 1) with pieces starting to fall off.   The treatment involves alum (aluminum potassium sulfate) dissolved in 90C water, a coating of linseed oil and a final lacquer.  Alum did not fully penetrate, only going in 5mm across the grain.  Cracks and voids inside the wood not easily seen.  Aluminum makes lignin complexes?  Is sulfuric acid being produced inside the wood?  Question is, now does the alum need to be removed, or is there a material that could be added to stabilize things?

Reconservation of Wood Treated with Alum in the 1920’s – Challenges and Strategies.

Inger Bojesen-Koefoed

We must be respectful of past efforts.  Otherwise, many of these objects would not be here at all.  Some kinds of objects look very different on exhibition as a result of their treatments and it is difficult for the public to interpret what that means.  Conservation history is another dimension of an object’s history.  Alum was invented as a treatment in 1859 and was popular for about 100 years.  It was the first method used to preserve archaeological wood.  There was shrinkage and collapse, often, and the wood looked dry after treatment.  Glycerol was added in 1900 as a possibility, but that went badly.  By the 1960’s PEG began to be used.  There was an attitude in the 1970’s and 80’s that all the alum treated wood needed to be re-treated with PEG.  There is a certain fashion aspect of conservation in terms of what an object ought to look like.  There is also the joy of learning a new method that makes these aesthetic sensibilities change, too.  Conservation treatments and the way archaeology was documented in past eras is really interesting and should be part of what we try to preserve.  If an artifact is stable, resist the urge to re-treat it in the latest fashion.  Consider leaving those old fills and old mountmaking styles in place as its own documentation.   

Accelerated Aging of Recent Oak, Impact from Iron Ions and Oxygen on Mechanical Properties in the Longitudinal Direction (poster)

Gunnar Almkvist, Charles Johansson, Ingela Bjurhager

Known that iron2+ in the Vasa is contributing to iron catalyzed processes in the wood (Fenton type reactions?) , they attempted to impregnate fresh oak with iron ions.  They think that the changed wood preoperties from the use of PEG occur in the radial and tangential directions because the PEG reduces the compression strength, but the iron affects the axial tension strength.  They found a 39% decrease in strength.  What about the ability of sulfur and PEG to inhibit degradation from iron? 

Removing Iron Compounds from a Waterlogged Wooden Gun-Carriage Using the Chelating Agent DTPA (poster)

Ebba Phillips and Inger Nystrom Godfrey

Needed to treat an oak gun carriage that was eroded, cracked, and had high levels of iron and sulfur.  Problem with citrate or EDTA is that you cannot put it down the drain.  DTPA (diethylene triamine pentaacetic acid) is a chelating agent that can be poured down the drain.  They used only 1%, which is half of what others have used, in 1000L of water, and removed a kilogram of iron in the first 40 days.  You need to do analysis of how much iron is coming out so you know when to renew your system.

Excavation and Stabilization of a 17^th Century Wicker Basket: New Application of a Known Method

Jill Barnard, Liz Goodman, and Nancy Shippen

Nancy Shippen is now at the MAC lab.  In 2006, a 17^th century willow basket was found in a controlled excavation and block lifted.  There were 2.5cm concretions inside.  They sprayed it with 20% PEG 200 and then 20% PEG 4000.  It was then vacuum freezer dried.  But how to remove the concretions?  They decided on glass beads of 44 micron diameter that have been used on bone, as the round shape of a glass bead was less likely to become embedded in the basketry.  They used the lowest setting on the machine, a scalpel, bamboo and compressed air.  Found this to be rapid and gentle, and they brush consolidated with 5% Butvar in IMS as they went.  When pieces came off (the willow had some intact bark) they used 2-3% Klucel G.  On the interior, they did leave some crusts in place if they were too tenacious.  Jim Spriggs comments that he’s had some success with vacuum tweezer in these situations, too.  Someone asked if the accretion could have been a clay meant to be there, but it seems the entire matrix was this material, so no, it was not meant to be part of the basket. 

Ship Caulking – the “Leftovers” from the Ship Conservation Projects (poster)

Anette Hjelm Petersen

Caulking between ship planks made of wool soaked in tar is removed during conservation in order to treat the wood as well as get a good look at the tool marks.  But there might be interesting information in that caulking material.  In the period 1015-1450, textile are rare in Danish sites.  When was the caulking material unspun yarn and when was it textile?  Are there differences in the caulking material between warships and merchant ships?  She is exploring these issues.

Rehabilitation and Monitoring of Waterlogged Archaeobotanical Remains from Southwest Florida’s Pineland Complex.

Donna L. Ruhl 

Unfortunately, there was no presenter for this poster.  The abstract involved a site excavated from 1988-1995, dated 50-1710AD.  The archaeobotanical collection including things like seeds and wood is being curated at the Florida Museum with some grant funding from the National Endowment for the Humanities.  Because this was the last day of the conference and I didn’t know there was no presenter, I missed the chance to look at the poster.

Conservation of a Marine Composite (Copper/Textile) from the 19^th Century Shipwreck “Patris” in Greece

P. Patsiri, C. Margariti, S. Rapiti

The Patris was a wheel steamship sunk in 1868 in the Aegean sean, with its two halves at different depths.  It was recovered in 2006.  The object being treated was a firehose fitting, where the hose attaches to a hydrant.  Calcareous accretions were removed with 10% formic acid on a local compress, and they also had 1% Hostacor in deionized water.  The fiber ID indicated the hose material was flax or hemp with a little bit of cotton.  There were also wood traces, but not enough to ID.  The hose also suffered from active corrosion as bronze disease and secondary deposition of copper as newly formed cuprite.  Sodium sesquicarbinate was used to treat the copper alloy.

Check out additional posts on the business meeting, specific WOAM personalities, the flavor of WOAM, and Lars Andersen’s advice to me on freeze drying at the AIC’s news blog.