Ceramic Pot Firing
The oven used to bake or fire clay is called a kiln. Kilns can be powered by electricity, wood or gas.
In an electric kiln clay object can necessitate up to 8 hours or more of firing. A wood kiln firing can take several days and necessitates a constant wood intake. A gas kiln is often used in raku style firing (see below).
Electric kilns for ceramics
Electric kilns come in different sizes and different heat ranges. There are kilns that are as small as a microwave oven and others are the size of walk-in closets. The majority of the ceramic pots on the market today are fired in electric kilns, ceramic industries use large room size kilns.
Fifty or so years ago electric kilns were energy hungry, like most appliances of that era. Modern electric kilns are energy friendlier; most of them are now programmable, which makes it easier to control the temperature can produce stunning colors and effects very closely imitating a wood or gas kiln. These kilns are mostly used by potter artisans and the pottery that they produce will be seen in exhibits, specialty art stores and in workshops.
Raku firing tecnique
Raku is a popular form of firing clay with a gas kiln (in most cases); most of these kilns are homemade using a steel barrel and heated with propane gas torches. It has it’s origin in Korea when Korea was under Japanese rule in the 16th century, how it developed is a mystery. Raku is a firing technique in which the ceramic pieces are removed from the kiln at a bright red heat and placed in containers of combustible materials; dried leaves, saw dust, newspaper, etc, once this materials ignite, the containers are closed and the ceramic pots are left to smoke for a while then the pieces are taken out of the container and put in water. This process affects the color of glazes and clay bodies. The drastic thermal shock from red hot to colder temperatures can produce crackling which makes for a very interesting ceramic pot.
Before electric kilns were built, clay was fired in a wood fire; this is still practiced today in its simpler form. Using a pit with low firing clay (Which does not require high heat to completely bake); the earth is the kiln and wood is used as the fuel or the source of heat. This also yields unpredictable effects.
There are many other kilns using wood as fuel. One of these and probably the oldest structured kiln is the anagama, it is a specific type kiln. It comes from the Japanese word for kiln, gama, with the addition of "cave", ana. in other words, a cave kiln. These were first developed in the third century BC in China. This technology later moved through Korea and Japan, where they got their name.
Wood firing is the oldest form of “baking” clay into ceramic and there are many methods of doing so. Berland uses an electric kiln and Raku.
Inside the kiln when the bottom element is at it<s full capacity.
The Raku Technic; the barrel is
lifted to have acces and remove
the objects that have reached
Close-up of red hot objects in Raku.