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follow-up on restoring damaged plaster molds

updated sat 31 jan 04

 

T. Phillips on thu 29 jan 04


Thanks again to everyone on ClayArt who took the time to provide assistance
and offer encouragement with this project. I'm nearing the end of my work,
and have achieved far more success than I ever would have anticipated.
There's nothing like watching a chunk of blackened plaster shatter
from being gingerly set on a table to discourage one.

After gently blowing off as much detritus and ash as I could, I
repaired and sealed the molds with a carefully thinned solution of
wood glue. Several people suggseted white glue for this purpose, but I
was concerned about its solubility in water. I found this layer had to
be extremely thin, or the plaster would later break apart in chunks
during the next step. Most of the molds had other substances melt onto
them, so it wasn't always easy to determine whether the glue was
adhering to plaster, or another substance coating the plaster. (Anyone
want to play "name that substance" for what could have caused a thin
layer resembling the backing of clear tape that covered some of the
molds?) In the case of those molds that had mystery materials on them,
this layer of glue later helped in removing anything adhering to the
plaster..

I then built up clay walls around the molds, and applied moulage
rubber molding compound. Low tech, but it worked like a charm. Only
two molds wound up with any plaster damage at all after the rubber
application; in most cases, the plaster looks better after the rubber
gently cleaned them. The moulage did tend to snag on any area that
was actually charred, probably because of the myriad little undercuts.
Once I had the rubbers, the rest was relatively straightforward -
pouring new masters of wax and plaster from the temporary rubber molds.

Again, thanks to everyone for their information and support.

T. Phillips
http://www.bluefrogcreations.com