Published Jan 21, 2022
Making a Paper Template
Cutting a Wood Slump Mold
With a marker, transfer the paper pattern onto a piece of plywood that is at least one inch larger than the paper pattern in all dimensions. Use a drill and jigsaw to cut out the pattern (figure 1). Start by drilling a hole just inside the traced form with a drill bit that is wider than the a jigsaw blade. Tip: Sometimes several holes make cutting complex forms easier. In this case, I cut three holes at each of the inner clover points. Next, slide the saw blade inside a drilled hole and slowly begin cutting along the pattern. Once the form has been cut and removed, hand sand the edge. Softening and slightly rounding this edge helps prevent unwanted shearing of the clay. Now your slump form is ready to be used.
Next, compress each side of the slab with a firm rib and then texture one side. I like to use self-made, bisque-fired, clay spindles or cords for texture (figure 2). The great thing about handbuilding with soft clay is how easy it is to impress while flat as opposed to impressing an already formed, leather hard, curved wall. Once textured, the clay is ready to be put in place. Drape the slab, texture side down, over the slump mold (figure 3). Lifting the clay-covered form from the tabletop immediately allows the clay to take shape. Tapping all four of the edges on a tabletop promotes further slumping (figure 4).
Now set the board and clay on wooden blocks or kiln posts tall enough so the draped clay does not touch the table surface. Wait the necessary time to allow the clay to become leather hard. I typically cover the slab with plastic and return the following day. The wooden form will absorb some of the clay’s moisture overnight. Once leather hard, the slumped slab can be removed from the mold and gently flipped onto a table. Next, cut a beveled edge, 1⁄8 of an inch from the outside edge (you will see a distinct line created from the wooden form) (figure 5). After placing foam on the mold (I re-use cone pack foam) return the clay to the form (figure 6). The foam prevents the clay from falling through after being cut.
Adding Walls to Form a Dish
Start by flattening coils of clay and cut them at equal widths. An extruder works great if you have access to one. I have made extruder dies from Masonite by cutting the wall cross section with a jigsaw in the same manner the clover mold was made. A string can be used to determine how long each of the three clover sides need to be. Next, attach the walls after slipping and scoring both parts (figure 7).