Consolidating panel painting

Petar Gerasimov asked for advice concerning the reinforcement
(consolidation) of several tempera panel paintings where the wood
has been greatly damaged worms.

We have treated Egyptian carved wood, some with polychrome surfaces,
some with a plain wood surface, which have been extensively attacked
by insects and by other biological agents. After initial cleaning
(where possible) we have introduced a 5-10% solution of Paraloid
(Acryloid)  B72 (an acrylic copolymer of ethyl methacrylate and
methyl acrylate) in acetone with a pipette. Allowing the solvent to
evaporate slowly by keeping the object in a sealed container helps
to encourage penetration and even consolidation and prevent
darkening of the surface. Further applications may be necessary and
more viscous solutions can be used to bond cracks or strengthen very
weak areas. Areas requiring support can be filled with Paraloid B72
dissolved in acetone and mixed with glass microballoons to form a
gap-fill. Large gaps can even be filled with pieces of polythene
foam (Plastazote or Ethafoam) shaped to be recessed below the final
surface, then covered with the Paraloid/glass microballoons mixture,
which can be tinted to match with fine dry pigments.

Any excess resin on the surface can be removed with swabs of a
suitable solvent, usually acetone.

Care must be taken because the wood may have degraded and
degradation products may be dissolved by the solvents.

The usual health and safety precautions must be observed when
dealing with solvents  and when dealing with the solid Paraloid
resin (which can form a dust hazard in large quantities). Hope this
helps.

Richard and Helena Jaeschke
Archaeological Conservators.


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                  Conservation DistList Instance 13:52
                  Distributed: Friday, April 21, 2000
                       Message Id: cdl-13-52-006
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