How to Make a Lovely Scalloped Rim Bowl with a Hump Mold and Some Coils Sarah Haven

Using a variety of construction techniques in your work can lead to exciting details in the finished pieces. Take, for example, the lovely contrast between the smooth, hump-molded bottom section of this bowl with the dimpled, pinched top.

In today's post, an excerpt from the September/October 2024 issue of Pottery Making Illustrated, Sarah Haven explains how she uses hump molds and coils to make her scalloped-rim bowls. –Jennifer Poellot Harnetty, editor

PS. Learn how Sarah creates her bold, vibrant surface decoration by reading the full article in the September/October 2024 issue of Pottery Making Illustrated! Not a subscriber? Subscribe today!

I was bitten by the clay bug about a year and a half into my stage management major at The Ohio State University in Columbus, Ohio. One class was all it took and I was hooked. The wheel was an amazing tool and I spent hours in the studio practicing. Eventually tiring of everything starting out round, I moved on to handbuilding. In graduate school, I focused on conceptual/site-specific work, but after several years I found myself less interested in spending copious amounts of time working on a single project. After some experimentation and figuring out what I love to do most in the studio, I found my way back to functional work, much to my surprise.

Creating the Base Form

I use various plaster and bisque hump molds for the bases of my pieces. Use whatever type of mold works for you. Begin by rolling out a slab with even thickness and large enough to fit your hump mold. Smooth the slab with a small Mudtools red rib before placing a round paper stencil with scalloped edges. Use a knife to cut around the stencil (1).

After carefully placing the slab on the mold, use your rib to smooth the slab, making sure it’s seated on the mold as well as removing the canvas texture from the slab. Let the slab set up on the mold until it’s soft leather hard.

Adding a Foot

From here on out, the rest of the building process is best done with the help of a banding wheel. With the slab still in place on the mold, roll out a coil, and decide where you want the foot. Score the area of attachment and use Magic Water (3 tablespoons sodium silicate, 1½  teaspoons soda ash, and 1 gallon water), or slip if you prefer, to attach the coil.

Use a wood tool where the coil and slab meet to properly attach the coil to the base (2) before pinching the coil up to make the foot (3). In addition to being a great-looking foot, it will act as a handle in the decorating process, so ensure it’s tall enough to get a good grip.

Once the foot has set up, remove the base from the mold so the entire piece can continue to firm up.

Adding Height

Roll out a coil, taking into consideration the thickness, depending on how tall you want the walls to be. I normally roll out a couple of smaller coils and piece those together to make one big coil, but the choice is yours. Score, apply Magic Water, and place the first coil, thoughtfully following the scalloped curves, while pinching and securing it onto the base (4). Do this on both the inside and outside of the piece. Now that the first coil is attached,roll and place the second coil (5). No Magic Water is needed since both coils are of the same wet consistency.

Next comes the pinching, which is my favorite part. Before you begin, make sure your coils are at a good working stage. If the clay is too wet to pinch up the walls without losing control of the piece, cover the rim edge with plastic and let it sit for 10–20 minutes before proceeding. Caution: If you wait too long, the slab base will pull too much moisture from the coil, making the base wobbly and the coil difficult to pinch without cracking. Begin by pinching the bottom coil. If you pinch the top coil first, the walls can get too tall for you to properly reach and pinch the bottom coil. At the same time, be cautious not to get the bottom coil so thin that it can’t support the top coil. This order of operations also ensures that the top coil doesn’t get too dried out when it’s time to finish the lip.

As you turn the banding wheel, keep your hands directly across from you at 12 o’clock as you pinch. This allows you to watch the walls as they rise, making sure to mimic the shape of the scalloped slab base as you go. After you feel that you have sufficiently moved the weight of the bottom, coil up into the piece and begin pinching the top coil. I choose not to smooth the two coils together, allowing a distinct line to mimic the rim and add to the aesthetic.

Once you have evenly pinched both coils as best as you can, finish up by giving the lip some extra attention (6). The lip is the first indicator to the user of the weight of your piece. If the lip is thick, the assumption is that the piece is heavy. Too thin, the piece can appear fragile. Work to find a nice balance.

After some time under plastic, cover the piece with an old sheet to complete the drying process. This allows the work to dry slowly and avoid warping. Once bone dry, apply three coats of terra sigillata to the slab base and foot, then use a piece of thin plastic to burnish the surface. I use a flimsy food-handling plastic glove to burnish (7). It’s so fast, you’ll love it.

Sarah Haven is a Midwest gal living in the Pacific Northwest. She received a BFA from The Ohio State University and an MFA from Central Washington University. You can see more at havenceramics.com, and buy one of her pots at saltstoneceramics.com in Seattle or northernclaycenter.org in Minneapolis.