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. ...

Objects of this type have usually been extensively restored.  I
often find several layers of coatings over a variety of fills and
restoration attempts.

Dianne van der Reyden and Donald C. Williams, in an article in the
AIC Meeting Preprints (14th Annual Mtg, Chicago, 1986:79-85,
available online at the SMCRE site) found that a rigid red crust was
gypsum mixed with an ester resin by IR spectroscopy but other layers
of an ester resin consisting of jalap and scammony.

On a similar object to that you mention, a CAL report 2871 authored
by Walter Angst and Eleanor McMillan, report that shellac layers were
chipped away with a wooden wedge and ethanol and methanol used to
clean it from other areas, but that methanol produced a black
substance from black treated areas.

I have often found insoluble coatings on such objects and the use of
a scalpel to mechanically reduce them was possible when I did not
wish to use solvent gels (especially since such gels can be
difficult to monitor unless used in limited areas at a time and even
then damage can be produce exceeding the occasional slip of a scalpel
blade).

There is a great wealth of information in the Postprints of the 1994
UKIC conference, Lacquerwork and Japanning.

In the end, Margaret Ballardie's brief not, "Conservation and
Restoration of Lacquer," ABPR Meetings Notes, 1998 in the Picture
Restorer. would be of interest to a student, as she emphasizes the
problems of trying to remove surface layers of restoration coatings
when they can penetrated into original lower layers of shellac and
cause havoc. She relies on emery cloth lubricated with white spirit.

I am sure you have done a comprehensive literature search and are
familiar with Marianne Webb's work on fill materials in lacquer
objects.  It helps to have here work as a reference when trying to
understand differences in areas of a lacquered object.

Niccolo Caldararo
Director and Chief Conservator
Conservation Art Service


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                  Conservation DistList Instance 20:30
                 Distributed: Friday, December 1, 2006
                       Message Id: cdl-20-30-001
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