Ribs are essential tools to any potter and they come in all shapes and sizes. But sometimes, you can’t find a rib that will do exactly what you want it to do. That’s when making your own ribs out of clay can really help. In today’s post, an excerpt from the Pottery Making Illustrated archive, Janis Wilson Hughes explains how she makes custom throwing ribs. – Jennifer Poellot Harnetty, editor.
It’s both empowering and satisfying to know you have the perfect tool for the job at your fingertips when you need it. Like many potters, my studio is overflowing with tools, including rubber ribs, texture rollers, bevel cutters, and countless other commercial and found tools. But occasionally it’s hard to find just the right tool to fit the current project. A couple years ago, a struggle to bring a particular thrown form to life led me to develop my own custom-shaped throwing and sculpting tools out of clay. A concept sketch I made of a zigzagging olive-oil bottle captivated me. When I tried to bring it to life on the wheel, I was able to create the zigzags on the top portion of the form, but no matter what I tried, I couldn’t get the bottom to take shape because my tools were too bulky. I needed something rigid like wood, but I’m not a woodworker. I am, however, a potter and saw no reason why fired clay couldn’t be used to make a custom throwing tool.
I made my first ribs from a groggy clay. It had some rough spots on the edges, which were smoothed out with a a 3M Diapad. I made a few prototypes and found that bisque-fired ones were great for pressing into leather-hard clay, as their porosity deters them from sticking to the moist clay surface, but they stuck to the wet clay when throwing. Vitrified ribs are ideal for working with wet clay because their hard, non-absorbent surface glides across the clay without sticking.
Making a Clay Rib
To make ribs, use an ultra-smooth throwing clay (I use Little Loafers cone 6 white stoneware by Highwater Clays for strength and the convenience of firing them along with my pots). This saves time and work when it comes to smoothing the edges of the ribs later. Determine what tools you want to make and cut durable templates from craft foam sheets or thicker cardboard.
Roll out a slab of clay to ¼ inch thick. Lay your templates on the slab and lightly trace them into the clay surface (figure 1). I use a bamboo skewer to do this. Lift off the templates and allow the clay to firm up to soft leather hard. Carefully cut out each rib using a sharp tool (figure 2). Move the ribs to a clean, smooth surface, and use a 45°-bevel tool to cut an angle into the edge of the rib around the perimeter (figure 3). If you have points or sharp angles on the rib, begin beveling at the point from one side, stop in the middle of the curve, then cut from the next point to the middle. This prevents the clay from tearing away at the points. Once you’ve beveled all the way around, turn the rib over, and do the same on the other side (figure 4).
When the ribs are leather hard, use a damp sponge to smooth the edges being careful to maintain the bevel. Stamp or carve your signature on the ribs at this point or use a hole cutter to make a hole in the middle to help grip the rib (figure 5). Lay the ribs out to dry on a clean, smooth, flat, absorbent wareboard. Place another wareboard on top to keep the ribs from warping. You may want to add a little weight on top of the board. Once they’re bone dry, fire the ribs.
To use the ribs for throwing, it’s important that they’re fully vitrified so they won’t absorb water and stick to wet clay. After firing the ribs, polish the edges to avoid causing fine scratches in your pots and to improve their handling. Use water, applied both on a diamond polishing pad and on the ribs, while buffing to prevent creating respirable silica dust. Always wear a dust mask when sanding clay.
Using a Clay Rib Your customized tools are now ready to use. Soak them in water for a few seconds before throwing with them and clean them when you’re done. Be careful with these clay tools since they will break if you drop them on a hard surface. But don’t fret if one breaks—now you know how to make another one.
Janis Wilson Hughes is a full-time studio potter and owner of Evolution Stoneware Pottery in Alpharetta, Georgia. She teaches adult ceramics classes in the Atlanta area.