Anyone used Alumina plastic for molds?

hoknok · Post by **hoknok** » Sat Jan 03, 2004 6:24 am

There is a product for the refractory industry for patching up cracks that has a plastic/clay like feel. Coming from a clay background, I was curious as to how good such a material would be for making molds? It has a high content of Alumina bonded with phosphate and silica. I am hoping to be able to mold this around objects for casting purposes. Just wondered how others have used the stuff? Thanks!

rosanna gusler · Post by **rosanna gusler** » Sat Jan 03, 2004 8:40 am

sounds interesting. almost everything else we use was origonally for something other than glass. looking forward to the report. do a shrink test will you? make a strip of the stuff and mark it while wet with a 10 cm line. measure again when dry and after firing. rosanna

Bert Weiss · Post by **Bert Weiss** » Sat Jan 03, 2004 10:35 am

I would give it a try. If there is a problem it will be heat shock. Pure alumina is quite dense and not fast heat friendly, like the alumina in a crucible. On the other hand cement is probably made for faster heat.