I first saw (and held) Birdie Boone’s belly-bottomed pots at an NCECA exhibition a couple of years ago, and I absolutely fell in love with them. Not only were the soft subtle colors contrasting with red clay body beautifully, but the pots felt so good in my hand because of the rounded bottom. In today’s post, Birdie explains the handbuilding techniques she developed for these pots, and the smart way she fires them to avoid slumping. – Jennifer Poellot Harnetty, editor.
I once read that certain monks had an eating habit that restricted the amount of a meal to what would fit into the volume created when both hands were cupped together. I looked down at my own cupped-together hands to see just how much food I could eat were I a monk, and I realized that hands were the original vessels used for consuming sustenance, and that the next best thing would be dishes that fit just so into that curve formed by two hands cupped together. Since then, ‘belly-bottomed’ dishes have become a significant part of my work.
Gathering Up the Pieces
My basic construction methods are slab building and coil pinching. I like to work on blueboard, (a type of drywall), because its smooth surface is denser than regular drywall and the paper covering is more durable. Note: Blueboard is used for skim coating, greenboard is used in damp areas prone to mildew. Blueboard is designed to absorb moisture from wet plaster. Tip: Cover any cut edges with Duct tape to avoid any plaster contamination to your clay.
When making a cup with a handle, I join two slabs together to form the walls of the pot, add the bellied bottom and a handle. To make a piece like this, begin by rolling out a few slabs. Try to work with slabs that are 1/8 inch1/4 inch thick (thicker for plates or larger forms). If you don’t have access to a slab roller, use a rolling pin to refine a thrown/stretched slab.
Before making any cuts, lift the slab from the blueboard to make sure it’s not sticking. Manipulating soft clay slabs is a bit tricky, especially when they are thin, so it’s important that they aren’t tacky. I have several paper templates that I have developed for various forms. There are lots of materials that could be used to make the templates; Bristol board (similar to cardstock) works well because it is smooth, flexible, and durable. The clay pieces that form the belly bottoms are cut using various cookie cutters that correspond in size to each paper template. For oval forms or larger forms, make templates or use container lids or whatever happens to work. Lay the templates down on the slab and carefully cut around them with a needle tool while gently holding down the edges of the template (figure 1). Once the cuts are made, remove the excess scraps and allow the pieces to firm up just a bit. Carefully move each piece to a smaller section of blueboard that sits on a banding wheel. Using a pony roller, bevel the seam edges and thin the lip edges (figure 2). For me, it’s important to have a quality banding wheel (one that turns effortlessly) so that the manipulation of clay is fluent as you use the pony roller. If you do this successfully, there is no need to clean up/soften edges once the pot is finished.
Note: Try to work in a series, making several of a given form at a time. By the time you have finished a step with the last one of the series, the first one is ready for the next step and you can proceed without having to wait for the clay to firm up or the need to re-wet. The quantity to work with depends on the complexity of the form.
Next, place a convex plaster or bisque hump mold on the banding wheel and form each belly-bottom piece over it by patting gently with your hands as the banding wheel turns in response to this action (figure 3). Smaller pieces can be removed fairly easily and quickly from the mold without distorting the curve; bottoms for larger forms require more time on the mold or a quick blast with a hair dryer to firm up enough to be moved without distortion. If the hump mold starts to get sticky with absorbed water, dust it with a little cornstarch or take a break and allow it to dry out. Lay each bellied pot bottom directly on the blue board to continue firming up. They need to be at least medium leather hard to hold their form during the assembly process.
Fitting the Pieces
Once all the pieces are cut out and the edges thinned, you can begin to assemble them into a form. To do this, gently bend each piece into a cylinder that will stand up. Use a little magic water as a joining medium it works like a charm and isn’t messy. Because this is wet clay and you’re applying plenty of pressure to ensure sound seams, you don’t need to score (unless you’re joining two pieces of unequal dryness). Using a paintbrush, apply the magic water to one side of each joint (figure 4) then position something firm (try using a plaster mold) behind the joint, and use the palm of your hand or a pony roller to compress the seam from the outside (figure 5). Apply enough pressure to make sure the clay particles are mingling nicely, but not so much that the visual line you’ve created is marred.
The following steps create subtle, but important parts of what makes these pot forms special. One of the effects of rolling the seam edges to miter them is that some of the clay moves, forming little peaks at the ends. When joining your two pieces together to form the wall of the cup, try to preserve these bits of clay and then fold them down to the outside of the pot’s wall (figure 6) once the two pieces are joined. Next, flip the cylinder upside down taking care not to squish the rim. Instead of folding these bits down as you did the ones on the rim, you will fold them in toward the center of what will be the interior of the cup (figure 7) so that they are on the same plane as the bottom of the cylinder wall. Once the cup is completely assembled, they will be visible in the bottom interior of the cup. These can now be considered part of the bottom edge, which you will vigorously score along with the bottom piece. Gently set the belly bottom down over the cylinder and work your way around the seam to make sure it’s aligned before applying pressure. Holding the form, use a paddle to compress the seam well to prevent cracking during the drying process (figure 8). Next, shape the wall into a curve.
For smaller forms like cups and small bowls, hold the form in one hand and use your other hand to stretch the wall from the inside, turning it as you work (figure 9). For a larger pot, set it upright on a piece of foam on the banding wheel and use a soft red Mudtools rib to stretch the wall from the inside while supporting the wall from the outside with your other hand. Once you’re satisfied with the shape, check the rim and re-shape it if any distortion has occurred.
To make a handle, start with a coil or two of soft clay. For this handle, two coils are joined with a little Magic Water. Place one coil on top of the other, press them together (figure 10) and then begin to stretch them back out by rolling with the large end of the pony roller. Once you have the width you want (it should still be thicker than the end product), roll each side with the small end of the pony roller until its edges are about the same thickness as the rim of the cup. Form a fake seam-line down the middle of the handle that creates a visual repetition of the wall’s seam (figure 11). I tend to wing it when it comes to handle length; cut a length that looks close, then plump the ends for a solid attachment. Hold the handle to the cup to check it visually and adjust the length if necessary. Once you have decided where to place the handle, score both cup and handle and join them together. Apply pressure to the joints firmly but gently to make sure the attachments are sound (figure 12). Do the final shaping of the handle after it is attached, considering the negative space formed by its silhouette.
A handle adds a little extra weight and, since the bottom is not flat, the cup will tend to list in the direction of the handle. To correct this, re-balance it by slightly shifting where the curve of the cup’s bottom meets the surface of the table, opposite from the handle.
A strong and durable pot is fully vitrified and to become so, it needs to be fired to maturation. When the clay particles are starting to melt together, this can cause physical shifting in an unstable form. If the body of the pot has too much weight for the belly bottom to bear, gravity will attempt to flatten it. To keep the bottom bellied, it needs support. When I first began making these forms, I fired them in little beds of silica sand carefully placed on the kiln shelves. This works really well, but it limits the number of pieces in a kiln load: putting little piles of sand too close to the edge of a shelf invites it to fall into any pots on shelves below. Because of this, I began to think about other ways to support curved forms.
I soon discovered the puki, a bowl-like form used by Native Americans to support a rounded base while coil building. So, instead of sand, I now use what have been coined (credit goes to Karen McPherson at Northern Clay Center) slump crutches (figure 15). These supportive forms are made with a cone 10 stoneware (I glaze fire to cone 6) so they don’t vitrify right away. I use the same cookie cutters and oval templates as I use for making my pots when I form these. I make them over the same plaster hump molds so they have the same or similar curves, but they don’t shrink as much, so the pots sit well in them for several firings.
Birdie Boone is a ceramic artist and educator currently living in northern New Mexico. To see more check out www.birdiebooneceramics.com.