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annbclay

Molding A Straight Sided Bowl

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Is it possible to make a plaster hump mold of a straight sided, deep Tuperware type container? I've tried it once, using Murphy's oil soap as a release agent but I can't get the plaster hump out without cutting off the plastic bowl. Any tips?

Ann B

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I use something called 'soft soap', not really a soap, but must be similar to what you already use. I've heard of some using the can spray cooking oil but I have never tried it. Good luck

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Is it possible to make a plaster hump mold of a straight sided, deep Tuperware type container? I've tried it once, using Murphy's oil soap as a release agent but I can't get the plaster hump out without cutting off the plastic bowl. Any tips?

Ann B

 

No art without sacrifice. The tupperware will go to its reward knowing it gave its life in a good cause.

Petroleum jelly might do the trick.

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Strait sides = friction and drag.

You can try "Burping" the mold. This is where you use compressed air to pop the seal between mold and master.

Other wise, cut the bowl.

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If there are no undercuts, petroleum jelly should work... at least it seemed to work well for making bronze casting molds from plaster. Normally one uses something with a slight inward slant to make releasing a bit easier.

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Is it possible to make a plaster hump mold of a straight sided, deep Tuperware type container? I've tried it once, using Murphy's oil soap as a release agent but I can't get the plaster hump out without cutting off the plastic bowl. Any tips?

Ann B

 

 

I use baby oil. It hasn't failed me yet.

Brenda

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Just a thought, but I like to use bisque molds. That is, if you're hand building--if you're pouring, then never mind . . . . I just throw a piece the size and shape I want, then trim the outside to be nice and smooth. That way I can coil/puzzle/pound my clay over the outside or make a smaller piece on the inside.

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