[Nhcoll-l] Aged Shellac

[Ann M Molineux]

Please can you reply to the list to Angie's query about shellac removal of historically collected 'shelly' materials in our collections (mainly molluscs, arthropods and echinoderms). Our real problems are the seeming lack of controlled experiments with helpful detailed methods and results which would allow us to do some meaningful tests. We have had the components of our 'shellac' tested (with many thanks to Julian Carter in Wales) and have a pretty good notion of the range of adhesives used.
This 'shellac' technique was used on our historic material and not something that has been practiced here, probably since the early twentieth century. So the specimens in question have been in the collection for over a hundred years. The matrix of Paleogene/Neogene is often friable and we suspect that may have been one of the reasons that shellac coating was adopted in the first place, they were never display specimens.
We are interested in your experiences with this problem and would appreciate any recommendations.
Many thanks
Ann

Ann Molineux, PhD
Curator and Collection Manager
Non-vertebrate Paleontology, Texas Natural Science Center
The University of Texas at Austin
Phone: 512-232-5384 (lab): Phone: 512-791-5521 (cell)
Location: Bldg 122, J.J.Pickle Research Campus, 10100 Burnet Rd, Austin, TX78758
http://www.utexas.edu/tmm/npl & http://www.paleocentral.org<http://www.paleocentral.org/>

From: nhcoll-l-bounces at mailman.yale.edu [mailto:nhcoll-l-bounces at mailman.yale.edu] On Behalf Of angie thompson
Sent: Tuesday, January 29, 2013 9:15 AM
To: nhcoll-l at mailman.yale.edu
Subject: [Nhcoll-l] Aged Shellac


Hi all
I'm looking at removing some very old 'shellac' from specimens. The shellac is about 80-100 yrs old, and has turned dark amber. This collection of specimens were covered in resin mix of  sandrac and copal. In some cases, we're seeing the shellac get brittle and fracture, damaging the surface underneath it.  Has anyone has success at aged shellac removal?
Thanks
Angie Thompson
UT
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