How to Combine Wheel-Thrown Clay with Slabs and Molds to Create Avian Inspired Forms Deborah Schwartzkopf

Combining different methods of building is an art—especially if you want it to look like one cohesive piece at the end. Deborah Schwartzkopf is a pro at building with wheel-thrown, handbuilt, and molded clay pieces. In this post, she demonstrates how she combines her different building methods to create a pitcher that is inspired by the birds that she saw on her travels. –Jennifer Poellot Harnetty, editor

Birds are a great starting place to study form. They’re full of life, vary greatly in shape, and have distinctive personalities. In Alaska, I studied loons and found them graceful in the water and sophisticated in form with an ethereal persona. Florida offered the pelican, which is a bit quirky in form, but no less elegant when gliding among the waves. These two birds were the inspiration for a new piece I’ve been working on.

I wanted a tall pitcher form, with a long full neck and a horizontal body that would be a resting place for the handle. Much like the pelican’s silhouette when it’s standing on a pier, the long beak aligned with its neck, and smallish body protruding horizontally. These proportions feel a bit awkward and playful. From the loon, I wanted the sleek sophistication and grace, to add a bit of mystery.

With these ideas of form in mind, I started with drawings of pots based to varying degrees on these birds. For this pitcher form, I wanted a shape that would be difficult for me to get with a thrown and altered part. So I coiled the shape I wanted, bisque fired it and used it as a mold for a slab of clay.

Overall Process

I assemble wheel thrown and altered porcelain parts and slabs that have been shaped over bisqued clay hump molds. In general I work as wet as I can—as soon as the clay does not show fingerprints when touched lightly—and with all the parts of a similar dryness. After the bisque, I apply different underglazes with a small tipped applicator bottle or airbrush. I then paint and wax small swatches of color, wax the insides after glazing, and begin to layer glazes through dipping and spraying on the outside surface. Glazing is not a fast process for me and I enjoy spending time at this stage of the process as well. I fire in an oxidation or neutral atmosphere (gas or electric) to a hard cone 10. On some pieces I airbrush china paint and fire a second time to cone 019. And at the end of the process, I want my work to be taken home and lived with, used during a meal, washed up at the sink, and when not in use, roosting in the cupboard.

Making Molds and Patterns

To make molds, I simply coil build non-round shapes, focusing on bisymmetrical angles and planes. These molds can be made out of most clays since they are only taken to bisque temperature. At times I build not knowing what the mold will be used for, and explore new finished shapes this way. Sometimes I have a specific drawing or picture in my mind and work from that to build a mold that gives me a particular form. I’ve learned that these molds can be used for many forms by laying different patterned slabs over them in different configurations (figure 1).

In conjunction with the molds, I use paper patterns made out of watercolor (or a heavy stock) paper (figure 2). These patterns give consistency and guide the clay shapes that I lay over the molds. These are used for cups, butter dishes, bowls, teapots, and other vessels. Each patterned piece, when laid on the molds in different ways, yields a totally different building block to play with. If I want to make several of the same form, I use a permanent marker to draw a line on the mold itself where the patterned slab started and stopped so I can put another slab on in the same place.

Making the Neck

To begin making the neck of the pitcher, throw a bottomless cylinder. I throw on bats to avoid denting the form as I lift it off the wheelhead. Center and open the clay through to the bat, draw outward until the clay starts to build a wall then compress down, flattening the wall. Repeat until the clay has moved out to the desired diameter. Here, I opened the centered clay to about 3 inches in diameter then raised the walls to about 6–7 inches in height. A slight swell adds to the volume even after altering the cylinder later on. Ribbing the cylinder takes off all the slip and shapes the profile into a tight strong curve (figure 3). Set the cylinder aside to dry to leather hard. Once it’s leather hard, cut out the darts on the front and back (figure 4). These darts are cut on a bevel, so that the clay meets on a roughly 45° angle rather than a 90° angle. This makes for a stronger seam that’s easier to compress. The altered cylinder now has movement and volume (figure 5).

Patterned & Molded Bottom

Next, use a bisque mold, paper pattern, and rolled out slab of clay (figure 6) to create the bottom portion. Creating the bisque molds provides the opportunity to make very unique pieces (see sidebar on page 18). To transfer the paper pattern onto the slab, simply run your finger along the edge of the pattern, pressing down lightly. The edge of the paper creates a slight line on the clay, which you can follow to cut out the pattern. However, only cut out the edges, leaving the darts to cut out after the slab is secured around the mold. In one sure movement, pick up the wet slab, wrap it around the bisque mold (figure 7) and slip and score together the beveled seam in the back (figure 8). If the slab is too dry, cracks can form as you bend the slab, and blending the seams together is more difficult. The support of the bisque mold under the clay allows you to press the clay strongly, blending the seams and defining different planes and lines on the form.

After the slab is secured around the mold, cut out darts that allow the clay to fit snugly against the mold (figure 9). When cutting the clay to take out darts, I use an X-Acto knife instead of a needle tool or a fettling knife. I find that using a thinner blade pulls less on the clay and makes for a cleaner cut. The blade is dull (I’ve been using the same one for years), which also ensures that you do not cut through the canvas, interfacing or other table coverings under your slab.

A good way to avoid that pesky canvas texture is to use interfacing—a non-weave synthetic fabric used in sewing to strengthen cuffs and collars. It can be found at fabric and craft shops and is quite inexpensive. Slip and score the edges and press them together. These dart seams should be further compressed from the inside once the clay is removed from the mold. Note: If too much slip is used on the seams, it causes the clay to stick to the mold and makes it hard to remove. After all the darts are cut and tucked, trim the upper edge and cut out the patterned top piece from a slab. Gently place it on top of the mold and slip and score it into place (figure 10). Some seams can be blended away and others developed, depending on where you want the glaze to break or the eye to be led along the form (figure 11).The clay stiffens quickly as the mold draws water out of the clay. If it is left on too long it will begin to crack. There is a small window of time where the clay is dry enough to support itself without the mold but not yet prone to cracking off the mold.

Finishing the Bottom

Once you’ve finished defining the body, set it aside. When the bottom is a soft leather hard, cut along the back vertically and then along the top horizontally to release it from the mold (figure 12). This allows you to remove the clay without damaging the shape. First take off the top, then flip the mold over and clam shell off the bottom, stretching the piece as little as possible as you widen it out away from the bisque mold enough to clear the sides of the mold and lift it off. It’s necessary to flip the mold over to remove the bottom on this particular form, because it tapers and becomes narrower towards the foot and would need to be stretched too wide to clear the top of the form if removed right side up. Next, now that the form is free from the mold, slip and score it all back together and smooth and compress the seams inside and out.

Combining Parts

To join the two parts together, the bottom form must be quite dry, otherwise it will sag under the weight of the top piece. The foot of the top cylinder must be trimmed in order for it to meet the curve of the bottom. Hold the top over the bottom to gauge where the cut should happen, trim it, and then hold it over the top again to see if it fits. Cut off more if needed. When the seam is flush, trace along the joint as a guide for cutting a hole. Cut just inside this line and remove the circle, then slip and score the segments together (figure 13). Press up from the inside of the bottom form to compress and smooth the seam. If you press down from the top, it can compromise the strength of the bottom. After this, place the pitcher body on a small slab, trace around the foot, cut out a closing bottom slab and slip and score this into place.

Finishing

Pull a thin strap handle from a lug or coil of clay. This can be pulled thinly because a clay slab is added later, and creates volume and visual weight. After the handle has dried a bit, cut it at one inch from the top at a roughly 45° angle. Attach the short section you just cut off to the neck of the pitcher. Face the cut angle away from the neck (with the bevel facing down) so that it will align with the longer section. Attach the remaining portion of your strap handle to the shorter piece, with the two cut faces meeting to create an acute angle on the inside of the handle, and a point on the outside edge of the seam.

After the attached handle parts are drier and won’t warp when touched, add a curved slab to the inside face of the longer section and coils inside the seam and shorter part of the handle to create visual weight and physical thickness that makes the handle comfortable to hold (figure 14). If this slab is too wet and the handle too dry there is a high risk of cracking. Pierce the pocket of air made by adding the slab with a pin or needle tool, so that it doesn’t stress the seam as the shrinking clay compresses the air inside or cause a blowout in the kiln. Cut and form a spout from a slab and hold it against the rim of the pitcher to see where to cut it. Trim the pitcher body and slip and score the spout into place. Blend in coils to form a smoother transition between the thrown rim and the cut slab edge (figure 15).

After the pitcher is assembled, compress the seams, add bits of clay to the uneven parts, and smooth out the rough areas with a wet sponge, rib and allow to dry. The finished greenware pitcher is ready for bisque firing (figure 16).

To see more of Deb's work, and for contact information, visit her website at https://ratcitystudios.com/.

**First published in 2010.