Stoneware Clay Technique

Stoneware is a versatile material suitable for various pottery techniques.

Stoneware clay is a high-fire clay that contains fine-grained mineral particles such as silica or alumina. The material is plastic, which refers to its ability to hold its shape and makes it suitable for handbuilding, mold-pressing and wheel-throwing. Stoneware is not porous after it is fired at appropriate temperatures, and it is most suitable for making functional objects such as tableware. Stoneware is typically glazed, which gives color and gloss to the pieces.

Wheel-Throwing

Wheel-throwing is one of the most commonly-used techniques when working with stoneware clay. This technique allows the artist to create work quickly and produce pieces that are not exactly the same but have a similar look. The artist attaches the clay to the wheel and starts the wheel, which spins around with the clay. The clay is raised, and the artist creates an opening in the clay, shaping the rest of the material into the desired form. The final step is to remove the piece from the wheel using a cutter, or a sturdy piece of string or fishing line. At this stage, creating a vase takes up to 15 minutes.

Mold-Pressing

Pressing stoneware clay into molds results in identical pieces, and the artist can replicate the same vase or object several times. The artist presses the clay into the parts of the mold. Molds come in two or several parts, depending on the complexity of the shape. The parts of the mold are joined, and when the clay slightly hardens, the artist removes the object from the mold. Making an object using molds takes up to an hour.

Handbuilding

Stoneware clay is suitable for hand-building because it is a pliable material. Artists use this technique to create unique shapes, figurines or sculptures. An artist may use clay slabs or individual clay coils to build a shape. Handbuilding is the most time-consuming of all pottery techniques, because the artist must allow the clay to harden before placing the next clay coils or slabs. Otherwise, the piece may fall apart. Building a vase, figurine or sculpture may take from a few hours to a few days, depending on the complexity of the design.

Glazing and Firing

Artists fire stoneware in an electric kiln. The initial firing is called bisque, and removes the water and makes the material stable. The second firing vitrifies the material, which refers to the high-heat process of making the clay nonporous.. After the bisque firing, the objects may be decorated with lead glazes, salt glazes and feldspar glazes, which are the three types of glazes available for stoneware. Stoneware clay vitrifies when fired at around 2,200 degrees Fahrenheit.

References

• Digital Fire: Stoneware Clay
• Chemistry Explained: Ceramics
• Goshen College: Learning to Throw
• Ceramic Arts Daily: Handbuilding Techniqes