Making a slump mold

[Anne W. Nye]

I'm collaborating with a metal artist doing figurative work and want to make a part of the figure out of glass. She can provide a plaster mold. Can I use insulating cement in that mold and then drape my glass over that? Or would you suggest some other material. I have lots of books but finding it confusing.????

[Bert Weiss]

To drape over you can use any refractory castable that shrinks more then glass (it must handle the heatup temperatures and process). Regular plaster/silica and variations meet this spec. I do not know about other castables.