Paraloid B72 as consolidant

Response to Gillian Comerford's query on use of B-72 as a
consolidant:

There are numerous references to B-72 used as a consolidant for the
strengthening of weak friable materials, including bone, but none
that I know of specifically for fossilized material.  I have used
B-72 extensively on dry bone, generally in the range of 5-10% in
acetone.  I avoid toluene "like the plague" and believe you can get
just as good penetration by modifying your solvent system by adding
ethanol, e.g. 90:10 acetone:ethanol (or even up to 80:20
acetone:ethanol).  I do not recommend exceeding 20% ethanol. (Note:
the ethanol should be added after initially dissolving the B-72 in
acetone, making it up to the percent you want).

I suggest you start with the numerous references on consolidation
for ceramics, bone and ivory, for information on the various methods
of application.  I wrote a couple of pages on consolidation in "The
use of Acryloid B-72 in the treatment of archaeological ceramics:
minimal intervention", pages 593-594 of the MRS Materials Issues in
Art and Archaeology II, vol 185, 1991.  Even though it deals with
ceramics, it is appropriate for other materials.

One cautionary note: you should save whatever samples are needed for
molecular biology/dietary studies, etc., before consolidation.  See
Moore, K.M., et al, "Dietary reconstruction from bones treated with
preservatives", JAS, 16 (1969), pp. 437-446.

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 9:28
                Distributed: Sunday, September 24, 1995
                        Message Id: cdl-9-28-003
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