Has anyone used Ultracal in molds?

dawirch · Post by **dawirch** » Wed Aug 13, 2003 8:35 pm

Most of the molds I've used for slumping/casting have been a 50/50 plaster/silica mix. I typically get one or two firings before the structure breaks down. I'm trying to find a stronger mold that is not ceramic or steel.

I often use Ultracal gypsum cement for non-glass, non-heated molds because of it's strength and ability to reproduce detail. It's a mix of gypsum and concrete(I think). What I'm wondering is if I can safely make a slump mold with 50/50 Ultracal and silica. This would theoretically make a stronger mold which would stand up to more firings. I just don't know how safe it is to heat the Ultracal to 1300+ degrees F.

ellen abbott · Post by **ellen abbott** » Thu Aug 14, 2003 10:36 am

Ultracal will work fine for that...so sez my mold maker.

E