David Dreading Pottery

The Potter’s Art

The production of pottery is one of the most ancient arts; the earliest known objects date back to 29,000-25,000 BC. The invention of the potter’s wheel in Mesopotamia, dating between 6,000 and 4,000 BC, revolutionized pottery production. However, by the late 19th century, with the development of machinery, the age of mass production dawned and the potter’s art consequently suffered. Its revival started in the 1930’s and many of the artist-potters arrived at their innovations by way of continuous experiment with materials and techniques deriving inspiration from primitive or ancient traditions.

Wheel Work

Wheel work makes great demands on the skill of the potter. The artisan must not only shape and form the clay, but create unique glazes, especially for those devoted to ornamental wares.

The process begins with the throwing of the clay on a potter’s wheel. When the pot becomes dry enough it is trimmed and cleaned. Because the glaze is molten and flows freely at high temperatures a catcher is thrown to fit the base of the recently trimmed piece. This will keep the glaze from fusing the pottery to the kiln shelf. After a drying period, the piece can be fired. The first firing is called ‘bisque.’ The bisque firing causes permanent chemical and physical changes to occur as the molecular water in the clay is burned off turning the malleable clay into stone.

Crystalline Glaze Pottery

The art of glazing pottery or ceramics is more about physics and chemistry than brush strokes. The glaze is a mixture of a glass component, usually silica, clay and a flux or melting material. In the crystalline glaze, zinc oxide is the main ‘magical’ ingredient. Zinc provides the seed from which the crystal can grow. The color is provided by elemental oxides like cobalt, copper, iron, and many others in specific combination.

The glaze firing is an intense process where the kiln temperature is raised to 2300 degrees Fahrenheit. A rapid cooling to 2000 degrees allows the seed crystals to begin to form. Holding that temperature for 4-8 hours is called ‘soaking’; at this point the crystals grow. The artisan’s variations in the colorants, soaking temperature, plus the daily atmospheric conditions cause tremendous variety in the ring and background colors of the final glaze. This is an exciting process that creates unique, one of a kind art pottery.

Raku Pottery

The last 25 years or so has seen the raku pottery technique become increasingly popular; it is a magical form of pottery that is both exciting and spontaneous. After the pottery has been bisque fired and glazed it is Raku fired to a temperature of around 1800 degrees Fahrenheit. The pottery is then removed and while it is still glowing hot it is placed in a metal can filled with combustible materials. The heat from the pottery ignites the material and the can is immediately sealed.

As the fire quickly uses all of the oxygen, it begins to draw it from the pottery and glaze. This process is called ‘post fire reduction.’ Reduction is what causes the incredibly unique patterns of color and metallic luster. When the pottery is removed it is immersed into water to freeze the shifting patterns. The clays used for Raku pottery are designed to withstand thermal shock—other clays would crack under the drastic temperature change.