Raku pottery is made using a unique ceramic firing process that incorporates both fire and smoke to produce distinctive patterns and designs. The piece is bisque fired first, then glazed and fired in the raku method. The firing process necessitates the use of a propane-fueled raku kiln that reaches temperatures of around 1,800°F (982°C).
The pottery must be left in the kiln for approximately 30 minutes to complete the firing process. Using specially designed raku tongs, it is then removed from the kiln. The raku pottery piece is placed inside a metal can full of combustible materials while it is still hot and glowing. These materials catch fire due to the heat emitted the pottery.
After the contents of the metal can catch fire, the lid is placed over the can and the pottery inside is sealed. Because it is made of a special type of clay that can withstand thermal shock, the piece can withstand these high temperatures and the fire within the can. The drastic temperature changes, on the other hand, would crack traditional pottery clays.
As the fire depletes the oxygen in the can, it also depletes the oxygen in the pottery and glaze. This is known as post-fire reduction. This stage is what gives raku pottery its distinct appearance. As a result of the natural process of oxygen removal, the resulting patterns and colors are unpredictable.
After about 15 minutes in the sealed metal can, the raku pottery is removed and placed in a can of water. This sets the patterns created during the post-fire reduction stage in stone. The length of time a piece should be left in the cooling water is largely determined the piece’s size and shape.
Because the process of making this pottery necessitates working with flammable materials and high temperatures, craftspeople should always wear gloves, protective clothing, and eye protection when working on a new piece.