Although I do gas and wood firing, Raku firing is my primary focus.

Raku is a Japanese firing technique invented in the 16th century for their tea ceremony; the Western world uses a modified version of it. Raku is the second firing of the piece, when it is heated up to 1000 to 1050 degree Celcius, at this temperature the glaze melts on the surface. Then, the pot is pulled out of the kiln with long tongs and placed in a container filled with combustible material (sawdust, newspaper, dry leaves, etc.) that burns right away. Closing the container creates a reduction atmosphere where the carbon (carbon comes form the combustible material) first becomes carbon monoxide and searches for more oxygen in order to become carbon dioxide. Due to the lack of air, the oxygen is taken from the metal oxides in the glazes. The metallic sheen and flashing colours are the result of the reduction process. There is another important reaction happening. In the smoke filled reduction chamber, the carbon penetrates the clay body, causing crackling and turns unglazed surfaces black.