About Raku
To briefly describe the Raku process it is helpful to understand that after the bisquing period (the process of vitrification) almost all other types of ceramics are loaded into a cold kiln where the firing proceeds slowly until the desired temperature is reached. This firing cycle may take anywhere from 8-24 hours or even longer. When the kiln has reached temperature it is shut off and allowed to cool enough to be able to remove the ware using bare, or lightly gloved hands. The cooling cycle may last from 12-24 hours or longer. The ware is considered finished when it is taken from the kiln.
In Raku method, the pieces may be loaded into a cold kiln but are often preheated and loaded into a hot kiln. The firing proceeds at a rapid pace with the wares reaching temperature (approx. 1800 degrees) in a cycle that may be as short as 15-20 minutes. Glaze maturity is judged by the trained eye without the use of cones or measuring devices. When the firing is completed the wares are immediately removed from the kiln. At this point the glaze is molten; tongs or other lifting devices are used for the move.
The wares are now subjected to a "post firing reduction" phase. They are quickly placed into a pit with a combination of combustible materials such as sawdust, pine needles or paper, and allowed to smoke for a specified period of time. The carbonaceous atmosphere reacts and affects the glazes and clay and imparts unique effects and surfaces to the wares. For example, some effects are metallic, while others may demonstrate crackled glaze surfaces. Where the clay body is not glazed, the clay absorbs the smoke and demonstrates Raku's signature, rich black. Once the wares have cooled, they are carefully washed to remove soot and ash residues.
In a related technique, identified as the "Horsehair Process," the burnished, unglazed ware is removed while red hot from the kiln and placed on a special work table. When the ware has cooled to approx 1400 degrees, horsehair (taken from the mane or tail) is applied to the surface to burn its distinctive patterns into the skin (or surface) of the ware.
How to care for your Raku ware:
Never place Raku in direct sunlight. Artificial lighting works nicely and is encouraged for highlighting the dramatic finishes of the ware. Hand wash gently in warm soapy water and allow to air dry. Never wash Raku in a dishwasher. Larger wall pieces can be rinsed in the shower and then air dried.