Pottery Process and Technique

Clayworks affords its students a superb environment for the exploration of clay. In addition to class time, registered students can use open studio hours scheduled several times during the week.

The Clay

Clayworks stocks several varieties of Laguna clay bodies. Most beginning students use brown stoneware clay. It is an all-purpose clay with a moderate amount of grog. Grog is pre-fired clay particles added to clay to give it extra durability, texture, and to reduce shrinkage. Brown stoneware is used in most classroom demonstrations. As a student's confidence grows, he or she may choose to explore other clay bodies including red stoneware, white stoneware, or porcelain. Clayworks also has two vacuum pug-mills to recycle the brown and white stoneware should the student decide it best to appreciate a work-in-progress as an “educational experience” rather than a “keeper”.

Before creating the pot, it is important to make sure the clay is ready for use. Wedging is a method of hand-working or kneading the clay to align and compress the clay particles and remove any trapped air. This is especially important for recycled clay, where the clay might be comprised of clay pieces of varying degrees of moisture and particle concentration. Any unevenness in the clay must be corrected before the clay is used for more precise throwing and to avoid any weak spots in the pot. The studio has several plaster wedging tables for this purpose.

Handbuilding

Clayworks has a slab roller and an extruder to create the basic components of hand-built pots. There are several approaches to hand-building. For instance, the student can press and smooth a slab of clay over one of the many plaster molds at the studio. Once the clay takes on the basic shape, additional clay adornments such as handles or appliqués can be applied. Another option is to create a coiled pot. This is an ancient technique where successive coils or concentric rings of clay are stacked, compressed, and smoothed into an even surface that gradually tapers or widens into the desired shape.

Throwing on the wheel

Although many students explore hand-built pottery, the majority of students focus on wheel throwing. Once the clay has been wedged, it is shaped into a balled mass and slapped onto the center of a wheel. A variety of electric wheels are available at the studio, along with several kick wheels having motorized-assists. Students do find the kick wheel a bit more strenuous and harder to master than the electric wheels, but with practice and patience one can gain the skill and coordination needed to master the kick wheel.

In the beginning classes, students are instructed in the methods of centering, coning, compressing the floor, pulling the walls, and shaping. In the advanced class the shapes go beyond the basics to include closed forms, lidded pieces, teapots, altered works, etc. In all the classes, regardless of level, students are encouraged to explore their imaginations to stretch and grow their skills.

Altering The Pot

A pot can be decorated at several stages along its development. While still fairly wet, the rim can be twisted or impressed with a stamp design. The rounded sides of a pot can be flattened with paddles. Once the pot is leather hard (cool to the touch, but not yet dry) the base can be trimmed, handles applied, or for added interest, a design carved into its sides. When the pot drys completely, a design can be painted-on using underglazes.

Bisque Firing

A pot will undergo two firings: a low-fire bisque firing and a high-fire glaze firing. A pot must be air-dried before it is bisque fired. The purpose of the bisque firing is to remove the remaining moisture from the piece and to make it more durable, while keeping a surface that is absorbent to glaze application. At Clayworks pieces are bisqued in an electric kiln. Kilns are fired to a certain cone level not just temperature setting. A cone level measures temperature over time to allow the necessary level of heat absorption into the pieces being fired.

Glaze Firing

After a piece has been bisqued, it is ready to be glazed. Two glaze firing options are available at Clayworks: a cone 6 electric firing and a cone 10 gas firing. The studio has a large variety of glazes tailored for these two cone levels. Multiple glazes can be applied to a single pot to achieve varying patterns and color combinations. The studio has an airbrush compressor the student can use to feather one glaze on top of another. Stains are another decorating technique, where selected areas of the pot are masked off and the stain brushed or sponged on to maintain an earthy tone and the tactile nature of the raw clay. Sample test tiles are available to assist the student in selecting the right glaze or stain to complement the piece.

The gas kiln delivers a hotter firing than the electric kiln. A reduction environment can be achieved in the gas kiln because the level of oxygen can be controlled. When the oxygen supply is reduced, the build up of carbon will cause oxygen to be extracted from the minerals within the clay and glazes to form carbon dioxide and carbon monoxide. Reduction firings can produce anything from subtle shade variations to more spectacular arrays of vivid color. The results in a gas firing are not as predictable as they are in the more controlled electric kiln firing, but it is certainly a way to get those one of a kind pieces.

Finishing Touches

After the pot is glazed and fired it may be desirable to apply additional non-clay adornments to complete the work. For instance, rather than a clay handle on a teapot, a bamboo or weaved rattan handle might be an interesting touch, or possibly the adornment is more functional in nature, such as a wire or a fine silk rope applied to a handbuilt wall hanging.

There are no limits to the variety and possibilities. Let lose your imagination, allow the vision to grow in your mind and take shape in the clay. Experiment and be bold. Be sure to check out the Clayworks Gallery to see samples of students' work.

Alternative Firing Techniques

Here are some brief descriptions of alternative techniques for firing pottery.

• Saggar firing uses a containing pot (the saggar) to enclose the piece during firing, often with the use of additional materials to create dramatic effects.
• Smoke firing combines smoke and heat to create interesting one-of-a-kind finishes to works.