The Process, Continued - Firing
Since electric kilns aren’t directly burning fuel, there are no flames and it isn’t generally possible to do reduction firing (i.e., firing in a reduced-oxygen atmosphere). There are glazes that are formulated to look like they’ve been reduction fired. Electric kilns can be equipped with electronic controllers that carefully regulate the temperature throughout the firing cycle. Some types of glazes (like crystalline glazes) require very precise temperatures held for specific periods of time, so firing these in an electric kiln with an electronic controller is the normal method. Electric kilns are very popular for bisque firing (i.e., the first firing), for potters who need to very carefully control the firing schedule, as well as for potters with limited studio space.
Gas and propane fired kilns can also be equipped with kiln controllers and even controls that regulate the oxygen content of the atmosphere. These are the workhorse kilns for larger studios and potters with very substantial production. These are much easier to control than wood-fired kilns or pit-firing, and give the potter the option to fire in a reduction atmosphere (i.e., an atmosphere in which oxygen is removed from the air), which yields some of the most beautiful glaze finishes.
Wood-fired kilns are often large, Japanese-style anagama kilns that take up to 7 days or even longer to fire, and might require a half a ton or a ton of wood for a single firing. Since the kiln has to be constantly tended, these mammoth firings are usually group efforts. Some traditional potters will fire these kilns only a couple of times a year, putting half their yearly production in each firing.