How to Make Plates and Bowls with Hump and Slump Molds

If you want to make a set of matching plates, dishes or a serving platter but you do not have a wheel, hump and slump molds are the answer. You roll out a slab of clay, shape it over or into the mold, and let the mold do the hard part. It is one of the most beginner friendly ways to make pottery you will actually use.

Hump vs slump: what is the difference?

• Hump molds are shaped like an upside down bowl. You drape the slab over the top, so the inside of your dish takes the shape of the mold.
• Slump molds are hollow. You press the slab down into the mold, so the outside of your dish takes the shape.

Some molds, like our oblong reversible mold, work both ways. Plaster molds also pull a little moisture out of the clay, which helps your piece release cleanly.

What you need

• A hump or slump mold
• Stoneware or porcelain clay, about 2 to 4 lb per piece depending on size
• A rolling pin or slab roller and two wood guides for even thickness
• A soft rib, a needle tool and a sponge
• Plastic to slow the drying

You can find all of the tools in our clay tools collection.

Step by step

1. Wedge the clay. Wedging removes air bubbles that can cause cracks or blowouts in the kiln.
2. Roll an even slab. Aim for about 1/4 inch thick. Roll in a few directions and flip the slab a couple of times so it does not warp later.
3. Smooth the surface. Run a soft rib over both sides of the slab. This compresses the clay and makes it stronger.
4. Drape or press. For a hump mold, lay the slab over the top and gently press it down with your hands, then smooth it with the rib. For a slump mold, ease it into the hollow from the center out.
5. Trim the edge. Run a needle tool around the rim of the mold to cut off the extra clay. Smooth the cut edge with a damp sponge.
6. Add a foot if you want one. On a hump mold, this is the time to add a coil foot ring or little feet while the bottom is facing up.
7. Let it firm up. Wait until the clay is leather hard, firm enough to hold its shape. On a hump mold, do not wait too long, since clay shrinks as it dries and can crack if it grips the mold.
8. Release and dry slowly. Lift the piece off, set it right side up and cover it loosely with plastic for a day or two so it dries evenly.

Firing and glazing

Once your pieces are bone dry, bisque fire them to about cone 04. Then glaze and fire to the range of your clay. For stoneware or porcelain that is usually cone 5 to 6. Keep the bottom free of glaze so it does not stick to the kiln shelf. Our guide on how to glaze bisqueware walks you through it.

Tips for better results

• Dust the mold with a little cornstarch if your clay is sticking.
• Keep it even. Slabs that are thicker on one side tend to warp.
• Make a set. Because the mold is reusable, you can make four or six matching pieces in one afternoon.
• Add texture. Roll lace, leaves or stamps into the slab before you drape it for an easy decorative surface.

Ready to try it?

Our new slab kits pair a mold with 12 lb of stoneware clay, ready to go. Try the slab platter kit, the oval dish kit, the deco dish kit or the square bowl kit. Prefer to pick your own clay? Shop all planter and dish molds and pottery clay.