Structural support for mural panels

At the Carnegie Museum of Art a team of conservators is treating a
group of bas-relief mural panels which comprise the Chariot of
Aurora by the French artists, Jean Dunand and Jean Dupas.   The
mural, dated 1935, is from the ocean liner, the Normandie.  The
substrate of the panels is plaster mixed with clay and a colorant.
This mix was cast into a copper alloy frame then carved after
drying.  The surface is decorated with urushi and gilding.

I am writing to inquire about the design of a structural support for
one of the panels, which is not structurally stable.  The dimensions
are 3'5" square and 1" thick.  The weight is approximately 55lbs.
There are numerous cracks in the surface and the panel tends to
torque during handling.  This panel has been previously stabilized
by a few different means.  There are screws through the framework
into the plaster, which has resulted in cracking of the decorative
surface.  There was a heavy application of new plaster with
incorporated iron struts, which corroded due to the moisture content
of the fresh plaster. After excavation of the restoration plaster
and associated corroded iron struts, it was revealed that the cracks
do not continue through to the verso.  Also, the original plaster is
somewhat friable and delaminating locally.

We are considering a four component epoxy system. The first
component would theoretically consolidate the friable and
delaminating surface with a low viscosity epoxy.  The second epoxy
of knife-grade consistency would level the surface and serve as the
underlying and upper coat for incorporation of a fiberglass cloth.
On top of the fiberglass and encased in the upper layer of
knife-grade epoxy, will be two parallel zinc-plated or
cadmium-plated threaded stainless steel rods.  This last component
is introduced to prevent movement in the panel. Although this system
will undoubtedly prove irreversible, we feel that it is warranted in
that it will provide the necessary support and strength.  Also, it
will not increase the depth of the panels significantly or add to
the perimeter dimensions.

These factors would interfere with the proposed mounting system for
installation of the mural. Because of the irreversible nature of
this treatment, we want to be sure to investigate all other viable
options before proceeding.  If anyone has had experience in
structurally stabilizing such a panel, designing a similar support
system, or if anyone is familiar with Dunand's carved plaster
panels, please respond here or contact

    Rhonda Wozniak
    Carnegie Museum of Art
    412-622-1978

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                  Conservation DistList Instance 12:7
                  Distributed: Thursday, July 2, 1998
                        Message Id: cdl-12-7-020
                                  ***