I have been making double-walled pottery for years. I love the voluminous feel of the forms, and the mystery that they hold for people who have never explored the technique. I entered graduate school using this technique for decorative applications, but as my interests turned to functional ware, the double-walled forms were temporarily shelved. However, after a few months of burning my hands on my microwaved ramen lunches (a graduate-school staple), it occurred to me that double-walled forms might be the solution, and my Chopstix bowls were the result.
These forms hold a robust volume inside, and when microwaved, the interior will heat up, while the air between the inside and outside walls allows the exterior to remain cool. They are ideal for heating up leftovers or giving an elegant presentation to a single-vessel meal.
I’ve now been making these for quite a long time. They were honored with “Best Thrown and Altered” in the “2010 Strictly Functional Pottery National.” Since that time, my glaze and glaze application have improved, and I now have the form dialed in so that they are conveniently stackable, have a good functional volume, and are truly a pleasure to use. I include them in nearly all my exhibitions, and they have become a signature vessel for me. The double-walled throwing technique can be used for any number of forms and should be explored with enthusiasm!
Clay Body and Glaze
I have formulated my own dark clay body. It fires chocolaty and beautiful in cone-10 reduction, or rich and subtle in a soda or wood firing. The dark color makes my white crackle glaze pop, and the elevated flux gives it a soft velvety look where there is no glaze. This clay body is extremely plastic, alters beautifully, dries without warping, and withstands firing to high temperatures and in various atmospheres. The crackle glaze has been very problematic over the years. Making it reliably food safe has been a challenge—if it flakes at all, it becomes dangerous for use. Increasing the flux in my clay body and adding bentonite to the glaze have solved the problem. It is still finicky to work with, but I’m now able to predict the results reliably, and know it to be food safe, dishwasher safe, and microwave safe. I use a limited glaze palette in my work, focusing on black, white, gray, and brown, and allow texture and contrast to enhance the forms. The dichotomy of the rich satin black with the intricate crackle sets up a lovely visual tension in these forms.
Throwing the Interior Wall
I use 4½ pounds of clay for each Chopstix bowl, and I always throw on a bat, as taking these forms off the wheel while wet causes enough alteration to prevent a level base. The bowls are thrown upside down. After centering, lower the form to a large hockey-puck shape and open all the way through to the wheel head. Opening slowly will keep the clay from pulling off center. I generally measure a few times to be sure that I have the correct diameter (5¼ inches (13 cm)) after tapering the interior (1). This tapering helps to ensure that the inside bowl does not become too large for the outside wall to encompass. There is no actual measurement for splitting the mass into the interior and exterior walls. Consider splitting it so that there is ⅓ for the interior bowl and ⅔ for the exterior bowl (2).
Now, it’s time to pull up the interior section. When pulling the interior bowl up, it is important to maintain conical, inward pulls. Be sure to remove any water before closing. Tip: To minimize excess water but still maintain lubrication for pulling, try dripping water onto your interior hand and letting it run down your fingers on the inside of the wall (3). This prevents a puddle from forming on the bat.
Closing the interior wall via collaring to form the interior of the bowl can be tricky. It usually takes me three rounds of collaring to close it without the telltale ruffling (buckling of sections of the wall) that often comes from closing too quickly. First, angle the rim in (4), then collar (5), then pull up and close in (6).
After the form is closed, use a soft red Mudtools rib to compress and then establish the curve of the connecting wall using a soft kidney rib (7). The standard kidney shape of this rib gives me a good cue when trimming. I know the shape of the curve, so I can trim with confidence even though I can’t see the connecting wall.
Throwing the Exterior Wall
Pulling up the outside wall takes a bit of finesse. Pushing too hard on the outside wall can collapse the curve of the connecting wall, so care must be taken to both pull up the base clay and to not press so hard that the connecting curve is altered. I use two or three pulls to lift the outside wall up and in (8). This wall also must be pulled in a conical, inward motion (9). As the wall moves inward, it becomes harder to get the water out of the interior. Tip: A sumi brush does a beautiful job of removing water without damaging the walls.
Once the water is removed, continue to collar in the wall (10), until the outside diameter matches the inside diameter of the internal bowl (11). Finally, be sure to rib off any remaining slip and compress the rim—which will be the foot. The final throwing step is to remove the excess clay from the outside of the form. While remembering the curve of the connecting wall, it is best to do a healthy undercut to help with drying and to simplify trimming (12). Finally, run a wire under the bowl, keeping the wire pressed down firmly. Leave the bowl on the bat until it is a soft leather hard.
Once the bowl is at the right firmness, remove it from the bat in a slow twisting motion and continue to dry it upside down on a vented surface. For drying, I prefer to elevate some pegboard (13). I also put a bat on the rim (foot) of the piece. This ensures even drying and eliminates warping of the foot.
Trimming these forms is a lot of fun, but it cannot be done until the piece is firm leather hard. If the connecting wall is too soft, the inside bowl will drop. After getting the form centered in the right-side-up position, I place a piece of fabric inside the bowl to prevent the shavings from sticking to what is normally the dampest part of the form (14). Trim the outside of the bowl first, remembering the curve of the connecting wall (15). Continue trimming the interior of the connecting wall. After lifting the shavings out of the bowl, continue to compress and refine the surface and curves with a soft rib (16).
Cutting the Chopstick Holes
Biscuit cutters can be found at most kitchen-supply stores, and they are fantastic in the studio! Use these to add the holes for the chopsticks. Soft pressure with these cutters allows for easy placement of the holes (17). Cutting into firm leather-hard clay takes some elbow grease, but slow rotation with the tool ensures clean, round openings. After making the holes, use a fettling knife to bevel the openings so the chopsticks can be inserted and removed without interruption (18).
Allow the bowls to dry slowly on a vented, elevated surface (such as a pegboard elevated on sticks) as there are two interior surfaces, two exterior surfaces, and a connecting wall that must all dry evenly. People who try double-walled forms are often discouraged by cracking during drying. Slow and steady wins the race!
Alisa (AL) Holen (she/her) is an associate professor of ceramics at the University of Southern Indiana in Evansville. She received her MA and MFA from the University of Iowa where she spent two summers working with Clary Illian. She has exhibited, nationally, and internationally and plans to spend her fall 2022 sabbatical at Red Lodge Clay Center in Red Lodge, Montana.