Raku (樂) is a process for firing pottery, developed in 16th century Japan. Raku was prized by the Japanese tea masters for its unique and timeless beauty. Pots are fired in a kiln. When the pots reach the desired temperature and the glazes have melted, the Raku pots are removed from the kiln. While still red hot, pots are placed in a pit of sawdust or other combustibles and covered so that the combustibles cannot burn freely. The chemical reaction between the combustibles and the molten glaze creates beautiful and unpredictable effects on the surface of the pottery. Metallic luster's and dark crackle effects are the hallmarks of Raku. Each piece, born of earth, water and fire is a unique creation, never to be duplicated.
Wood Firing is a demanding process requiring intensive labor in both preparing the wood and firing the kiln. Even a modest size wood kiln consumes a cord of wood. Stoking for 20-30 hours can be an exhausting experience, but the results achieved are worth the effort. Wood kilns are fed smaller diameter pieces of wood. Depending on the stage of the firing, stoking may take place as frequently as every 3 minutes. The potter mast pay constant attention to the kiln from start to finish.
A gas fired kiln attains temperatures of 2400° F. By controlling the ratio of oxygen and gas, an atmosphere can be created with an abundance of carbon monoxide. This "reduction cycle" is responsible for the unique pallet of colors that develop when carbon monoxide molecules seek out chemically bound oxygen in the clay glazes.
Cone 6 electric fired stoneware pots are fired in an electric kiln to a temperature somewhere between 2232° F and 2264° F. The kiln fires for about 13 hours and then is allowed to slowly cool. The kiln is opened at 150° or less, which is usually about 24 hours after it finishes firing.
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