using bisque molds 4.7.2022

As a ceramic handbuilder, it’s nice to have molds on hand. I can use a mold to make several matching pieces, or to quickly create a form to build off of. Molds are typically made from plaster, but I don’t want plaster in my home studio because 1) it takes more equipment that I don’t have room for in my small home studio, and 2) I’ve heard more than a couple times about ceramic artists who regret allowing plaster into their studio because any plaster fragments that get left in clay end up destroying a vessel during firing. So I use bisque molds (although I do own a couple plaster molds which I bought early on.)

Bisque molds are made from clay. I make a form – a bowl or platter or whatever form I’d like – out of clay. I make it thicker than usual, because I want it sturdy enough to last a long time. I fire it to about 1915 degrees, or cone 04, which is a “bisque” firing, hence the name bisque mold. I want a mold that sucks up the moisture out of the clay, and bisque ware does a marvelous job at that. In a future post, I’ll show you how I create my bisque molds. But for now, I want to demonstrate how I can use both the outside AND the inside of the bisque molds to make different pieces.

This is a bisque mold I made. When I opened the kiln, a piece from this round bowl form had fallen off. This could be the result of an air bubble or other detritus in the clay.

I attempted repairing it with Elmer’s glue, because I thought the porous bisque ware would suck up the glue. But the Elmer’s wouldn’t hold. So I used super glue, then sanded the edges to make the surface more uniform. You can see there are obvious gaps where I mended the mold, but they hardly show on the clay form that’s made from this mold.

The round bisque mold is underneath this red clay. I drape a slab of clay over the outside of the bisque mold and gently form it to the mold, then add a foot at the top. So what you’re looking at is an upside down bowl resting on the round mold.

Here, I’m using the inside of the mold to press clay in to.

Once the mold has sucked up moisture from the clay, the new clay form easily comes away from the bisque mold.

Here are the new bowls, the one on the left formed on the outside of the mold, and made from red clay with a large foot added. The bowl on the right is formed from the inside of the mold, so it’s a little smaller. It’s made from stoneware clay, with a foot added. Once these are completely dry, I’ll bisque fire, then glaze fire them.

So this is how I use the bisque molds I create. I’ll post soon about how I make these molds. Stay tuned!

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