Here is the post as promised;
The Contenti Co.
123 Stewart Street
Providence Rhode Island 02903
The name of the material is Moldex synthetic mold rubber. It
comes in flat sheets and has the consistancy of modeling clay.
You use it like vulcanizing rubber, it is easier to pack as it
has a clay like consistancy. It cooks about the same temperature,
but about 30/60 minutes longer. Cuts very easily with a tear
strength very like RTV silastics. I have 20lbs of castildo gold
setting untouched since i found the Moldex. It gets my vote!!