Casein paint on wood

Jane Foley <jfcfoley [at] sbcglobal__net> writes

>Galeazzi Prune <galeazziprune [at] yahoo__fr> writes
>
>>I am leading a research project on the preservation-restoration of a
>>casein paint layer ...
>
>Wishab (vulcanised latex) soft version is what I would use. It has
>amazing results but its use depends on having a stable not friable
>painted surface, the latter requiring preconsolidation.

I have never worked with this material, so I have no
idea about it's properties, but it raised two concerns
for me: (a) vulcanized and (b) latex.

Vulcanized means sulfur content. Sulfur content means potential
chemically unstable off-gassing of smelly corrosive fumes (although
these are less of an issue with wood).

Latex means rubber. As an adhesive, my experience of rubber
compounds is very short lifespans, chemical instability, nasty
degradation products, and irreversibility. My experience with rubber
artifacts has been that they shrink phenomenally--to a fraction of
their original size, and have become incredibly brittle and fragile,
like eggshell.

It is this past experience that leads me to hesitate at hearing a
recommendation of vulcanized latex to treat a friable paint layer. I
can understand that initially the results would be good: latex would
have a nice flexibility to it, but it's the long term that concerns
me. Can anyone enlighten me on why my initial reaction to this
product may be wrong? Again, I admit to no previous experience with
this material, so I don't know about its lifespan, reversibility,
degradation etc.

Valerie Tomlinson
former conservator


                                  ***
                  Conservation DistList Instance 20:43
                  Distributed: Tuesday, March 6, 2007
                       Message Id: cdl-20-43-005
                                  ***