Carving into a form is a great way to add imagery and texture to pottery. But Michelle Swafford came up with a different twist on carved texture. She carves a design into a leather hard slab, then makes very thin sprigs from that carving, which she then adheres to the surface of her pots. She then takes the decoration a step farther by carving additional detail in the attached sprigs. Genius! Read on for the details! – Jennifer Poellot Harnetty, editor.
ps. This post is excerpted from the January/February 2015 issue of Pottery Making Illustrated. To learn the rest of the process, see the January/February 2015 issue of PMI!
Using Sprigs to Develop Texture
by Michelle Swafford
Creating a Sprig Mold
I create my sprig molds by carving Japanese-inspired line drawings of botanical images into leather-hard clay slabs. To begin, roll out a ½-inch-thick slab of non-groggy clay and dry it between layers of newspaper and drywall boards until leather hard.
Transfer your image to the slab by placing the print against the slab and tracing the image with a dull pencil (figure 1). Carve the image into the slab, varying the line quality and depth to create an active image (figure 2). Avoid carving lines that are more than 1⁄8 inch deep, as this may cause the pressed sprigs to tear. Dry the sprig mold between layers of newspaper and drywall boards until bone dry, and then bisque fire it. Alternatively, you can cast a ½-inch-thick plaster slab and carve your image directly into the plaster. Be sure to wash away all plaster dust from the mold before using it with clay.
Throwing and Trimming
Using four to five pounds of clay, throw a low, wide 12-inch platter that has a shallow, continuous curve from the floor to the rim, leaving about a 3⁄8-inch-thick floor. Using a rib (I use a fan-shaped rib cut from an old gift card), scrape clay from the center of the floor to create an 8-inch-wide well. It’s important to remove enough clay so the well sits about 1⁄8-inch lower than the rest of the platter, as this will allow the final sprigged surface to be flush with the platter frame.
Create defining lines around the center well using the point of a wooden knife (figure 3). Use the knife to also define a line about 3⁄8 inch below the rim. These lines provide a guide for carving the platter frame, and help to keep glaze colors separate during the firing. Trim the foot when the platter is leather hard.
Rolling and Cutting Sprigs
Roll out an 1⁄8-inch-thick slab of porcelain. Store this slab on a plastic-covered ware board, and cover it with additional plastic so it doesn’t dry out. Cut a 4-inch square piece of the slab and roll it between pieces of smooth canvas or newspaper until it’s very thin, almost to the point of tearing. Alternatively, you can roll thin slabs using a pasta machine, but be sure to sandwich the clay between canvas strips so the clay doesn’t stick to the metal rollers.
Cover the thin slab with newspaper or smooth canvas and press the slab into your sprig mold with your fingers, just until you can see a faint outline of the image on the back of the clay (figure 4). Peel the pressed slab from the sprig mold (figure 5) and store it between plastic. Continue thinning slabs, pressing them into the mold and storing them in plastic until you have enough to cover the center of the platter.
Next, place one of the pressed slabs on a plastic bat and cut it out using an X-Acto knife (figure 6). Place the cut sprig back on the plastic-covered ware board and cover it with plastic immediately. Repeat with the remaining pressed slabs. If necessary, you can lightly mist the sprigs with water to keep them soft.
Applying the Sprigs
Layer the cut sprigs over the platter well, experimenting with placement to create an interesting composition. Pay attention to the shape of the negative space in the center of the platter. You can sprig the entire well of the platter to be flush with the platter frame, or leave a little window in the center for visual interest. Work quickly and lightly mist the sprigs if they’re getting too dry.
Once the sprigs are in place, lightly press near the edge of the center well so it shows through the sprigs (figure 7). Using an X-Acto knife, cut away the portion of each sprig that lies outside the well (figure 8).
Using the overlap of the top sprig as a guide, cut through the sprig below and use the X-Acto knife to remove the excess sprig from underneath (figure 9). This allows the sprig pieces to fit together like puzzle pieces. When all the sprigs have been cut to fit, lift one sprig up and brush a thin layer of thick porcelain slip onto the back (figure 10). Place the sprig onto the platter, being careful not to trap air bubbles beneath it. Repeat, going around the platter in one direction until all sprigs have been slipped and repositioned.