Plaster adhesive

Margot McKay Wright <ant011 [at] abdn__ac__uk> writes

>We have in our collection a number of calcite and alabaster bowls
>from Egypt.  They have been reconstructed using a white insoluble
>adhesive which, when tested, gave positives for sulphate and
>protein--a casein plaster? The repairs are unsightly and the
>adhesive has been smeared over the surface of the bowls. Does anyone
>know of a way of reversing this medium?

I had last year serious problems with the removal of a layer of
paint made basically of Barium sulphate, lead white and casein.
Having tried more conventional methods without success I
used--successfully--Nitromors Varnish and Lacquer Remover (the one
in the brown tin) diluted with white spirit. It is slow but very
controllable (I had to preserve the underlying layer of paint, but I
do not know how it would affect the alabaster). Dichloromethane did
not work on its own. I guess the proportion of methanol in Nitromors
is what did it.

Dominique-Anita Rogers, BSc.
Ganapati Kumari, Pin Mill, Ipswich, IP9 1JW, UK

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                  Conservation DistList Instance 11:67
                 Distributed: Friday, February 6, 1998
                       Message Id: cdl-11-67-003
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