Removing lacquer from stained glass

Response to Simon Hogg's inquiry on the possibility of a cellulose
acetate lacquer having been used on a medieval stained glass window: it
seems to me that cellulose acetate would be a poor choice owing to
its high water absorbency, and would likely show a crazed or
wrinkled appearance. Perhaps it was a cellulose acetate-butyrate,
which should be soluble in acetone or, if hydrolyzed, soluble in
methyl ethyl ketone or methylene chloride.  Shellac is a definite
possibility, but is unlikely to have been mixed with cellulose
acetate (assuming your IR to be correct).  In any case, I would try
a cotton poultice using 50:50 acetone:ethanol to test for
solubility.

Stephen Koob
Department of Conservation and Scientific Research
Freer Gallery of Art
Smithsonian Institution
Washington DC 20560
202-357-4880 x276

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                  Conservation DistList Instance 9:57
                Distributed: Wednesday, January 31, 1996
                        Message Id: cdl-9-57-005
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