Gas, Electric, or Wood Kilns
Q: My new place in Washington State has a brick barbecue, which I plan to use for a wood-fired kiln. But the place also has heavy electricity and natural gas. Which is better for ceramics, a wood kiln, a gas kiln, or an electric kiln?
A: If this is a barbecue built with common red bricks, you could melt the whole thing if you take it up to stoneware temperatures. Converting it into a kiln would require a firebrick lining at the very least. Although gas is cheaper to fire with than electricity, this differential is less in the Pacific Northwest than elsewhere in the US.
It is certainly easier to use electricity, as the kiln can be controlled automatically, shutting itself off upon attaining a certain temperature with its simple mechanical “kilnsitter.” There are optical pyrometers which are used to power solenoids for the same function in industrial gas kilns, but these are priced out of reach of most studio potters.
Wood kilns are the most labor intensive of all, requiring constant attendance for what can turn out to be days on end. Gas kilns are better than electric ones if one desires the effect of “reduction” firing, in which an abundance of fuel uses up the available oxygen in the chamber’s atmosphere, causing characteristic changes in the color of glazes and the clay body itself. Wood-fired kilns are supposed to impart more individuality to the ware, with more accidental effects from the fire.
“Oxidation” firing, which occurs in electric kilns, will produce different colors from the same glazes fired in reduction. Some colors, like copper red, will not work unless one can reduce the kiln. But bright colors come out cleaner in oxidation, and many effects are easier to control. Why not buy an electric kiln to get started, then build a gas kiln later? That way, you could fire both at the same time, (and really spin your meters!)