How do you use plaster of pair in a plaster mold. What kind of barrier do you use, and how to get it out?

Question

I have recieved free plaster molds of all shapes/sizes and styles. I do not have a kiln and can not afford on. I heard you can use the plaster molds with polymer clay, thats ok for the small ones and the single sided molds. But I have also heard that you can put some sort of a barrier of Pam Spray or vasaline, etc...on the plaster mold and then pour in the plaster of paris. How long does it take to set, how do I get it out of the mold? Any more other suggestions?

Answer 1

I think chevy man is refering to a brush on/pourable latex rubber.

If your mold has lots of nooks and crannies, the plaster is going to be hard to release as the plaster grabs onto them from all angles and can't be pulled straight off.  The rubber is flexible and can be peeled off after removing the plaster backing it.

You can get a mold release spray (basically a spray wax) at auto part and boat supply shops or anywhere that has a good selection of fiberglassing materials.

The rubber can be gotten from fabrication supply, craft supply and costume supply shops as it's used to make face molds.

Answer 2

You need access to liquid rubber,a compound. Make a mold, pour in the liquid rubber, only making it a quarter-inch thick.Let dry over night, then use that with your p. of p. Use a air blower to blow down the sides of the mold. This makes this process much easier to retrieve your part. Let me know if this helps.   JMS

Answer 3

idk