Lacquered papier mache tabletop

Ruaidhri O'Bolguidhir <ruri [at] eircom__net> writes

>I am a student of conservation and restoration and have been
>assigned a papier mache tilt-top table as my current project. The
>table-top is lacquered and has mother of pearl inlay. It also has
>decorative gilding and a floral scene painted on the surface. All of
>this is covered with a thick varnish layer. This varnish layer is
>almost opaque and completely obscures the painted areas and gilding.
>
>The varnish on the surface is very stubborn and solvent tests
>carried out have shown that dichloromethane is the only effective
>solvent. ...

I have worked on a lacquer papier mache tabletop with a
difficult-to-remove varnish, and the varnish turned out to be
(probably) an alkyd resin.  The reason I say that is that it behaves
similarly to a type of varnish I have found on a number of highly
restored paintings and objects, one of which I had analyzed.

If this is what  you have, the trick to getting it off is that it is
not soluble, but it swells, just not right away.  Often, repeated
applications of acetone (allowing the acetone to evaporate each
time) will set off tiny bubbles, and the film starts to break up.
Once the process starts, you know what you have, and you can try
different solvents or mixtures to get it going faster.  You have to
wipe away the little lumps of resin--they never do dissolve.
Sometimes methanol works better than acetone.  The films are quite
shiny and smooth, so they feel slippery under a wet swab.  If you
are not paying attention, you may think that what you have is a
naked paint film.

It may be, of course, that you have something else entirely, but I
suspect that many objects and paintings have this stuff on them, and
it's worth giving it a try.  It took me quite a few years to figure
out what it was.  So far, I have only found it on restored things.

Barbara Appelbaum
Appelbaum and Himmelstein
444 Central Park West
New York NY 10025
212-666-4630


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                  Conservation DistList Instance 20:28
                 Distributed: Monday, November 27, 2006
                       Message Id: cdl-20-28-002
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