Neptune ^06 Raku 4oz RAKU FIRING ? Raku glazes can be fired anywhere from 1600 F up to cone 06 (1850 F) in either an electric or gas kiln. We recommend firing 850 to 856 and 868 to 879 to a peak of 1700 - 1750 F and 860 to 866 to a peak of 1600 - 1650 F. They should be allowed to cool in the kiln to 1600 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 lidded metal garbage can or small metal container that has been lined with organic material, such as newspaper and/or sawdust, etc.). 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.