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The ceramic fish that we specialize in are of a particular ceramic firing process called "Raku." Raku, as practiced today, is derived through procedures developed by Japanese potters from the 16th century. Today, potters modify the traditional Raku firing process by using more conventional methods of firing, including the use of propane tanks (instead of wood and coal fires) and metal containers full of combustible material (instead of holes in the ground full of leaves) in which the Raku art is placed after firing.
When we raku fire, the pieces are removed red-hot at 1,900 degrees Fahrenheit, and placed in a pile of combustible material, such as sawdust, leaves, or paper. The material immediately ignites and a metal container is put over it. Lacking air, the organic material releases carbon gases that affect the body and glaze of the piece. Due to the severe drop in temperature when the piece is removed from the kiln, the glaze shrinks faster than the clay body. This causes "craze" lines (small cracks) throughout the piece. These hairline cracks are made prominent by the deposit of carbon in them – turning them black. No matter what color clay is used, the cracks and exposed areas of clay will turn black due to carbon deposits.
Creating a raku fish is a difficult process, but one that produces distinctive, beautiful, and individual results. |
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The kiln is carefully loaded. A propane burner mounted under the kiln, brings the internal temperature from 70 degrees Fahrenheit to 1,900 Fahrenheit in under an hour. |
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A hole in the wall of the kiln allows us to monitor the fish as the kiln temperature escalates. If the temperature goes beyond 1,900 degrees, all the glazes will become too liquid and melt off of the fish. At the moment the glowing orange fish have a glossy appearance it means the the glaze has fluxed ( gone from solid to liquid). IT IS TIME!!!!! |
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The stage is set. Metal containers are set next to piles of combustible material (wood chips) ready to receive the 1,900 degree fish. The two people who remove items from the kiln dress head to toe in protective clothing. |
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The kiln door is opened. Metal tongs are used to reach in and remove the glowing hot fish. Assistants stand ready.... |
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The fish are quickly set into the wood chips. Additional wood chips are sprinkled on top. The glaze quickly transitions from a liquid to a solid. If the surface of the fish is enveloped in fire, than the glaze will have made the transition in a reduction ( oxygen free) atmosphere. |
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A metal container is firmly planted over the fish and burning material to create an enclosed space. The fire quickly consumes all of the available oxygen in the atmosphere, and then initiates a series of chemical reactions that rip oxygen atoms out of compounds in the the clay and glaze of the fish. Remember from chemistry 101, heat ( 1,900 degree fish) is a catalyst for chemical reactions. |
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After a 10 minute waiting period the fish have undergone their chemical reactions. They have cooled to a more stable temperature around 900 degrees and are less likely to experience thermal shock when the metal containers are removed. the fish are picked up with tongs and set in water. This causes the glaze to rapidly cool and contract which leads to minor cracking over the glaze surface. |
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After 30 minutes, the fish are cool enough to handle. With a quick scrubbing to remove carbon deposits, the fish are in their finished state. |
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