From: Neven Peko <neven.p...@gmail.com> Subject: [Consdistlist] conservation of mammoth bone and tusk
Dear colleagues, Do you have any idea how to consolidate [mammoth tusk] without using solvents such as ethanol or acetone? We would prefer to use a water-based system because of health risks. Also, a large part of our mammoth bones collection was treated in sixties by immersion in diluted PVA or PVAc glue (white thick wood glue). Do you have any idea how to chemically remove it without affecting the very porous bone? Also, do you have any suggestions on how to consolidate bone previously treated in this manner? Thank you all! Neven ------------------------------ Neven, While I'm not an ivory expert, here are my thoughts. Ivory tends to be a pain to safely dry if it is found in a wet or high RH environment, though not impossible. If it's stable it's potentially easier and safer to keep it in the same environment, as you have, than anything else. Could it be displayed in a tank of distilled or deionized water? Being a river, I'm guessing it was found in fresh water which is a plus as salt water can cause delamination of ivory materials and efflorescence when dried. Drying of waterlogged ivory can also cause warping, splitting, etc. of the ivory if nothing additionally is done, or even if it is. If you check the Consdistlist archives back in 1998 there was a discussion about waterlogged ivory and controlled drying that may give you some things to try. Ian Godfrey from, at that time, the West Australian Museum is noted as carrying out a study on drying waterlogged ivory. It appears he has retired but seems to still be active as a conservator/researche r. If you're able to safely dry the ivory after speaking with some people that have experience in that area you may have much better luck and more options for consolidation than working with it while wet. If drying isn't appropriate you may want to look into options utilising polyethylene glycol (PEG) as this is often used for waterlogged materials. I've seen note of employing silanes in such situations I believe (a similar process is noted here for with regards to stone and alkoxysilanes, I haven't read through the whole thing but it seemed to be the most relevant source I could come across: https://www.getty.edu/conservation/publications_resources/pdf_publications/pdf/alkoxysilanes_vl.pdf). A 'silane treatment' can also be combined with an acrylic resin if the surface is particularly friable to give a greater adhesion, how this would work with waterlogged items would need to be investigated. Depending on your specimen you may not have the greatest result due to the density of ivory versus other similar materials with either of the above options. One thing to note, if the piece is purely a display item with little research value a consolidation treatment isn't an issue. If the piece is noted as having research value consolidation should be avoided as this can reduce or eliminate the ability for researchers/scientists to work with this particular item and obtain useful information. One compromise if you need to remove it from the bath would be to work on the majority of the item but leave a small part untreated, even if the untreated part cracks, so that testing and research could be carried out without issue. All that being said, many small to medium sized general history museums likely wouldn't be able to carry out the above treatments in-house for reasons of equipment or cost. Possibly a national level museum has access to or the ability to carry out such treatments. As mentioned above, if you're able to carry out a controlled drying your in-house consolidation options will expand and see costs lowered. PVAC has been used for bone consolidation in the past so it's not surprising you have mammoth remains treated in this way. It could also be another 'white glue' but that's hard to say unless you have well documented records so you may choose to go ahead with assuming it's an unknown. Depending on the scale and condition you may choose to consolidate as is or remove the previous consolidate and consolidate anew. The number one thing I'd say is don't immerse the bones in water or employ a humidification setup in an effort to loosen or re-adhere the consolidate; dry bones and water/considerable RH increases they don't mix well. A conservator with experience in treating bones may have a reasoning after seeing the items in person for submersion of dry bones but it's not something to be done without proper experience. A national museum in Croatia might be able to give some specialised advice or you can trying contacting the Croatian Conservation Institute or the Canadian Conservation Inst itute. If you want to try taking off the consolidate, try spot testing with water and see if the material on the bones is soluble. If it is, great. Work a small area at a time with a minimally damp swab and even drying the spot with some cotton immediately after. As you noted the bone will likely be quite porous so it'll be important to not get it too wet and to start in an inconspicuous area. Take care with the friability of the surface if it's in poor condition. This may take forever depending on your collection, so some decisions may need to be made as to how to proceed or other options. If the water doesn't work you may need to try various solvents. Others may have suggestions that will be less time consuming or better for use on bones; I haven't had to deal with large scale glue/adhesive removal on bone and I'm assuming the mammoth bones are quite large and numerous. There may be a larger scale way to deal with them. Good luck! William Shepherd Collections Officer Swift Current Museum 44 Robert Street West Swift Current, Saskatchewan S9H 4M9 Phone: 306-778-4815 Fax: 306-778-4818 ****** Unsubscribe by sending a message to consdistlist-le...@cool.conservation-us.org Archives through August 2016 at http://cool.conservation-us.org/byform/mailing-lists/cdl/ Archives from September 2016 onward at https://www.mail-archive.com/consdistlist@cool.conservation-us.org/