Ceramic molds are usually made out of plaster for use with liquid clay slip, while some may also be used as presses for clay slabs. Plaster Molds are used in pottery because they absorb water out of the clay as it dries. This keeps clay from sticking to them, and helps reduce warping. The molds that we currently carry are for texturing and/or forming slabs of clay and not slips of clay. If you are looking for slip-casting molds, where you pour slip into a mold to form an object, we do not carry those. We do however sell the casting slip used for them.
While we may not carry slip-casting molds, we also carry Glass and Slump-hump molds. Glass Molds are made of ceramic (not polymer) so they can be fired in a kiln. These glass molds can also be used for forming clay and work similar to plaster since clay does not stick to them. While Slump-hump Molds are polymer and are often used as is or as initial molds create your own plaster molds.