Raku
***This is an extremely Americanized version of an Ancient Japanese art form. I am apologizing in advance to any purists, but this is how I do it.***
Raku is the art of regulating the amount of oxygen the piece receives during a critical period of color formation. Alternating between deprivation and overdose forcing the color to change rapidly and create flashes of different colors.
You start off with a bisque fired vessel and apply raku glazes accordingly. In raku glaze application is best done with a mop vs. eyeliner. This does not mean to dump on volumes of glaze, use only the recommended amount or it will all run off the vessel. Any fine details done with small delicate brushes will most likely not appear in the finished piece. A little hint here, clean the bottom of the piece so the glaze does not stick the vessel to the shelf or brick.
Place the vessel inside the kiln once the glaze has dried. We use a propane fired kiln, but it can also be done in electric kiln or I recently heard a friend of mine was going to start raku-ing from the front door of his wood kiln as he fired it for his regular work (cone 10).
The kiln is fired and watched through peep holes. It is fun to watch the glaze change from the muted color it was when it was applied to the crusty black as it gets hot. The color then starts to glow red-orange and when the chunks melt down it is ready to remove from the kiln. Typical temperature range is 1800-1850 F.
While the piece is firing we build the reduction chamber. This is where you starve the glaze of oxygen. We use sand pits and build a nest out of sawdust and shredded paper covered with a tin garbage can for our reduction chamber. You can also use the can upright filled with materials and use the lid to seal it. The reduction materials can be anything that burns, paper is the easiest and
cheapest to obtain, but also dried grass, pine needles, leaves, manure, or straw to name a few more.
The glowing piece is transferred using large tongs from the hot kiln to the reduction chamber. The chamber is sealed and the fire will burn out the oxygen creating the reduction environment. After a few moments the chamber can be opened briefly to allow the oxygen back into the glaze. If you watch closely and have your timing right you can watch the color change across the
piece. But be careful, with the oxygen going back in, the fire can flare up again and has cost a few people some eyebrows and eyelashes. Quickly seal the chamber again to capture the color.
Allow several minutes to pass and you can open the can again, or leave it till it cools, the larger the piece the more “burps” of air it will need. Once it has cooled enough, depending on your clay body, you can start to apply cool water to stop the color changes, and freeze it. Be careful this can also shatter your piece if the clay is not shock resistant or has flaws in its construction.
After the piece as completely cooled, wash any remaining soot off the piece. For crackle finishes you may need a mild abrasive to clean the scum off of it. Any areas that did not receive glaze will be gray/black and will need to be sealed with a brush or spray sealer.
Raku is the art of regulating the amount of oxygen the piece receives during a critical period of color formation. Alternating between deprivation and overdose forcing the color to change rapidly and create flashes of different colors.
You start off with a bisque fired vessel and apply raku glazes accordingly. In raku glaze application is best done with a mop vs. eyeliner. This does not mean to dump on volumes of glaze, use only the recommended amount or it will all run off the vessel. Any fine details done with small delicate brushes will most likely not appear in the finished piece. A little hint here, clean the bottom of the piece so the glaze does not stick the vessel to the shelf or brick.
Place the vessel inside the kiln once the glaze has dried. We use a propane fired kiln, but it can also be done in electric kiln or I recently heard a friend of mine was going to start raku-ing from the front door of his wood kiln as he fired it for his regular work (cone 10).
The kiln is fired and watched through peep holes. It is fun to watch the glaze change from the muted color it was when it was applied to the crusty black as it gets hot. The color then starts to glow red-orange and when the chunks melt down it is ready to remove from the kiln. Typical temperature range is 1800-1850 F.
While the piece is firing we build the reduction chamber. This is where you starve the glaze of oxygen. We use sand pits and build a nest out of sawdust and shredded paper covered with a tin garbage can for our reduction chamber. You can also use the can upright filled with materials and use the lid to seal it. The reduction materials can be anything that burns, paper is the easiest and
cheapest to obtain, but also dried grass, pine needles, leaves, manure, or straw to name a few more.
The glowing piece is transferred using large tongs from the hot kiln to the reduction chamber. The chamber is sealed and the fire will burn out the oxygen creating the reduction environment. After a few moments the chamber can be opened briefly to allow the oxygen back into the glaze. If you watch closely and have your timing right you can watch the color change across the
piece. But be careful, with the oxygen going back in, the fire can flare up again and has cost a few people some eyebrows and eyelashes. Quickly seal the chamber again to capture the color.
Allow several minutes to pass and you can open the can again, or leave it till it cools, the larger the piece the more “burps” of air it will need. Once it has cooled enough, depending on your clay body, you can start to apply cool water to stop the color changes, and freeze it. Be careful this can also shatter your piece if the clay is not shock resistant or has flaws in its construction.
After the piece as completely cooled, wash any remaining soot off the piece. For crackle finishes you may need a mild abrasive to clean the scum off of it. Any areas that did not receive glaze will be gray/black and will need to be sealed with a brush or spray sealer.