Spectrum's Raku glazes produce exciting colors and surfaces when raku fired. Remember that these glazes need to be fired using the Raku process to produce the results you see on the color chips. They should be fired between Cone 011(1600deg; F) to Cone 06 (1850deg; F) in a gas kiln. (Spectrum recommends firing #850 - #856 to a peak of 1700deg; F - 1750deg; F and #860 - #866 to a peak of 1600deg; F - 1650deg; F.) Then they should be allowed to cool in the kiln to approx 1600deg; F. (Different combinations of peak temp and reduction starting temp will produce different results.) While still red hot they should be transferred as quickly as possible into a reduction bin - typically a metal garbage can or small metal container with a lid that... Read More
Spectrum's Raku glazes produce exciting colors and surfaces when raku fired. Remember that these glazes need to be fired using the Raku process to produce the results you see on the color chips. They should be fired between Cone 011(1600deg; F) to Cone 06 (1850deg; F) in a gas kiln. (Spectrum recommends firing #850 - #856 to a peak of 1700deg; F - 1750deg; F and #860 - #866 to a peak of 1600deg; F - 1650deg; F.) Then they should be allowed to cool in the kiln to approx 1600deg; F. (Different combinations of peak temp and reduction starting temp will produce different results.) While still red hot they should be transferred as quickly as possible into a reduction bin - typically a metal garbage can or small metal container with a lid that has been lined with organic material, such as newspaper, sawdust, hay etc. Use raku gloves and tongs. As soon as the pieces are in the bin the lid should be put on to keep oxygen from entering the container, in order to develop the reduction atmosphere. The pieces should be allowed to cool in the bin for at least 20 minutes before being removed and quenched in water. Pieces should be cleaned immediately with water and a hard bristle brush. After cleaning, warm the pieces in the kiln to evaporate any water from the piece. This helps to set the colors more permanently.
Raku pottery is never Dinnerware Safe due to the irregular surfaces and crackled nature of the glazes and clays. Raku ware is not watertight. All of Spectrum's Raku glazes are not Dinnerware Safe and Toxicity Ratings vary: see lsquo;Specs' under individual colors for this information.
When the red-hot pieces go into the bin the organic material ignites producing flames and smoke, so this part of the firing, particularly the opening of the reduction bin, should be done outside in a well ventilated area. Always take safety precautions when firing raku such as the use of high temperature gloves
