The clay used in this process is formulated to withstand extreme temperature changes. Pieces are first fired in an electric kiln. The specialized kiln used for this process uses propane for fuel and is outside. The pieces are pulled out of the kiln at approximately 1800 F and placed in air tight containers with combustible materials. This creates flame and smoke, the reduction process induces the glazes to produce a rainbow of colors. This is a fast process, but gives amazing, unique results. The pieces fired Raku are for decoration only, they will not hold water.