Tina’s Techniques

The ingredients in my sculptures are made in the slow, traditional manner. The process requires water patiently dissolving mountains over a period of several billion years. Natural clay is composed of minute stone particles created by grinding glaciers and trickling streams.

Though all natural clays have been created by weathering and erosion, their composition varies widely. I use a ball clay from Tennessee. It has a finer grain than kaolin clays. A great percentage of its particles are smaller than a micron. (a micron is a millionth of a meter). The phrase “ball clay” originates with early English clay mines. It was common practice to create large balls of damp clay in the mines to roll out and onto horse-drawn wagons. The Tennessee ball clay I employ is much lighter in color than the English ball clay.

Clay is a wonderful material. It can be manipulated into almost any shape. Its plasticity is quite unique among natural materials. The reasons for its great plasticity are not completely understood. The most likely explanation is that the billions of tiny particles clinging together in one of my unfired works cling together for much the same reason two wet pieces of glass cling together.

I sculpt with clay that is approximately one third water. Many of my pieces are thick and heavy so I always make sure the drying process is extremely slow. The surface dries first as the water in the clay begins to evaporate. The evaporating water causes the particles of clay to draw closer together. Thus, during the drying process, the sculpture shrinks about 20%.

After the clay is completely dry, I fire it in the kiln. Firing transforms the clay both chemically and physically from easily crumbled to rock hard. Fired clay will remain in its new state for millenia. There’s no room for spontaneity in the firing process. Some of the bigger, heavier pieces require a pulley system to lower the piece carefully into the kiln. I then program a computer controller to guide the kiln through a number of steps- slowly increasing, then slowly decreasing the temperature.

Each piece is fired twice. The first firing is called the bisque firing. The bisque firing completes the drying process. I must fire extremely slowly during the first 300 degrees. If the temperature increases too rapidly, steam from within the clay can actually cause an explosion. The work may not be completely dehydrated until 500 degrees is reached. The clay is heated to cone 04 (1940 degrees), at which time it is red hot. After a sculpture has been bisque fired, I apply the glaze by painting, dipping, or spraying. Sometimes this process takes as much time as making the sculpture.

My glaze is composed primarily of glass frit. Frit is glass that has been melted and poured red-hot into cold water. It then explodes in a zillion tiny shades. It is further ground to a uniform powder. Silica is the primary ingredient in the frit as it is in almost every other glass. Silica is hard and durable. Over 50% of the earth’s crust is silica. I add a bit of kaolin clay to stabilize the clear glaze and increase its viscosity. My clear glaze is composed of frit, silica, and kaolin. Like the clay body of my sculptures, the glaze consists of tiny particles of rocks and mineral. The piece is then fired to cone 06 (1830 degrees). The piece slowly cools down before I can open the kiln. It’s like waiting for Christmas!!!