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Woodfired Clay Colors
Owen Rye reviews a woodfire/salt glaze body

lashing colors are typical of woodfiring, usually where a reduced atmosphere has been use in the higher temperature ranges, followed by an oxidised cooling. The flashing colors are very dependent on the nature of the clays used, and generally low iron clay bodies fluxed by felspars produce an orange coloured flash.

I have for many years been working at improving color response in woodfiring, both in glazes and on the clay itself. Rather than dull browns and tans I want reds, pinks, oranges and apricot colors. Experimenting for many years with clay body composition led to RSF, a woodfire/salt body sold commercially in Australia by Clayworks. RSF is one of the few specially formulated commercially available woodfire clay bodies in the world (the others being in Japan, e.g. Shigaraki clay). It has proved over the years to be very durable in the most testing woodfire conditions such as anagama firing, and even refiring multiple times, a practice that destroys most stoneware bodies. It has been successfully fired up to Cone 12-13 in the anagama but is best around Cone 10 for color development. Under the right firing conditions, RSF could produce strong pink/apricot/orange colours underneath wads, or where the clay was sheltered from direct flame.

Recently, because one of the materials in RSF became unavailable, the opportunity arose to experiment with further improvements in RSF. The new composition allows an even richer flashing quality.

In common with the earlier version of RSF, the new clay is also suitable for saltglazing. It has good throwing characteristics and is especially suitable for large pots, which I make by the coil and throw method. It is also used as a handbuilding body especially for large-scale work. I use it sometimes as paperclay, mixing shredded newspaper and some paper pulp into the commercial body in a clay mixer. This does not alter its firing characteristics in any way but allows making difficult shapes, and larger forms are much lighter than when made from the standard RSF.

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