Raku means “enjoyment”, “comfort” or “ease”
Raku ware (楽焼 raku-yaki?) is a type of Japanese Pottery that is traditionally used in the Japanese Tea Ceremony, most often in the form of tea bowls. Raku firing is expressive, exciting and fun.
Raku firing is one of the most exciting processes in ceramics. After you place your pottery into a raku kiln, the anticipation builds as you wait for that final moment when the intense heat begins to melt the raku glazes. You remove the pieces when the glazes begin to melt, you can feel the heat and hear the pings your red hot work rapidly cooling, then it’s into the raku combustibles for a round of flame and smoke. Many surprises await you as you clean the surface and reveal the wonders of raku pottery.
To carry out a sawdust firing the ceramist packs the work in sawdust in a simple kiln structure, sets the sawdust on fire, and allows it to burn until combustion ceases from lack of fuel. As the sawdust burns, rich patterns of carbon smudging are left on the surface of the piece. Pieces fired in sawdust have a natural and direct quality that can be very appealing. Sawdust firing has the advantage of being economical. The firing is carried out in a simple firing container rather than in a true kiln.
Pieces intended for the sawdust fire are burnished wih or without or terra sigillata, followed by bisque firing in regular kiln. The sawdust fire is very effective with these surface coatings and the fire markings are emphasized.
Traditionally, saggars, a container to hold glazed ware were made primarily from fireclay.. The purpose was to protect the pots from ashes open flame, smoke, gases and kiln debris, as kilns were coal or wood fired, the name may be a contraction of the word safeguard. Their use is widespread, including in China, Korea, Japan and the United Kingdom. Modern saggars are made of alumina ceramic, cordierite ceramic, mullite ceramic silicon carbide and in special cases from zirconia.
From the twentieth century studio potters have used saggars to create decorative ceramic pieces. In this use saggars are used to create a localised reducing atmosphere or concentrate the effects of salts, metal oxides and other materials on the surface of their ware.
Pots are carefully prepared for saggar firing. One method creates a smooth surface covered with clay slip, terra sigillata, which responds particularly well to the saggar technique. This slip covering is burnished to achieve a gloss. Prepared pots are nestled into saggars filled with beds of combustible materials, such as sawdust, less combustible organic materials, salts and metals. These materials ignite or fume during firing, leaving the pot buried in layers of fine ash. Ware produced in filled saggars may display dramatic markings, with colours ranging from distinctive black and white markings to flashes of golds, greens and red tones. Porcelain and stoneware are ideal for displaying the surface patterns obtained through saggar firing. In addition to the use of saggars, some studio potters bundle pots and burnable materials within a heavy wrapping of metal foil.. , mainly Aluminium foil.
The firing is done till the foil is disintegrated, around 850/900 degree centigrade.