Raku firing provides instant gratification for the artist! Glazed ceramic pieces are taken out of the raku kiln, glowing red at around 1850 degrees Fahrenheit. These pieces are immediately placed in a combustible material inside a steel can to produce flashing, crackle effects and rainbow metallic finishes. Each firing takes about 30 minutes or so. The ceramic piece is usually cooled within an hour, showing the highly variable effect.