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is there a way you can use random ceramic items for slumping molds if you drill holes in them? I don't think you can but why not? I'm talking like using a plate out of your cupboard as a mold for example.

For best results you need unglazed ceramic ware, commonly called bisque ware in the ceramics business.

If the item is glazed (as anything in you kitchen cupboard would be), then it's best to sandblast the glaze off. It's riskier, but if you're willing to sacrifice the item, you might try it anyway without blasting -- it's harder to get kiln wash to stick, but sometimes you can get away with that if the sides aren't too steep.

Isn't it easier to take a plaster master mold and model a new clay mold with it?
That way you can eat and save your plate.

See this thread, everything you wanted to know but were afraid to ask.........Jen

http://www.warmglass.com/phpBB/viewtopi ... =2&t=40145

thats great info, thank you for posting

The problem with slumping directly into a lot of dishware/serveware is that you're slumping into the inside shape of the vessel. The outside/bottom of the dish is designed to sit flat and give a particular silhouette, and that's usually what you want.

The inside of the dish is usually smoother and rounder so that it's easier to clean/eat soup from/whatever. That means the glass slumped into may not sit flat and may not give you the shape you want.

That's not to say you can't modify the dish to get it the way you want, but it's more work.

One caution with using ceramics to make slumping molds: Unless you're using a flexible mold material, i.e.,one that can be peeled away from the dish, think about how you're going to get it OUT of the mold. Even without undercuts, suction and the draft of the piece can get it stuck in the mold. Use plenty of release, and keep compressed air around to help separate them.

In the industrial ceramics world, they make molds, using the same process as they use to make kiln shelves. They call these molds saggers. They are designed to hold plates during the final decorating firing, so the plates hold their shape. These make good slump molds. I bought some from Shenango in PA, many years ago.