As mentioned in the spring issue of the SustainLife journal, we recently began building a wood fired kiln. We have been using a gas-fired kiln for the past twelve years, but due to some design flaws and repair needs, we decided to build a new one. This new wood-fired kiln will be a big step toward sustainability for us, as potters. The only cost in firing the new kiln will be our labor, as we will be able to heat it by burning scraps of wood.
We started laying bricks in March, 2012, and as of May 21, we have completed the construction of the fire boxes, the walls of the firing chamber and the arched roof. The next thing we will build is the chimney.
Most of the kiln is built from dry-stacked, high-temperature, insulating fire bricks, in a double-walled construction. The fire boxes are an exception, as they are mortared together and constructed of very hard, dense higher-temperature brick. These high-duty fire bricks can handle the intense heat of the fire boxes better than the insulating bricks used throughout the rest of the kiln.
The arched roof is also made of dry-stacked brick. To lay those bricks in place, we built an arch former of wood. It’s top surface matches the shape of the kiln’s arch. We braced the arch former from inside the kiln, then laid the bricks in position on top of it. Once the arch bricks were all in place, we removed the arch former, allowing the roof to stand on its own, held in place by the weight of the bricks, the side walls and the design and shape of the arch.
We have done most of the work with volunteer labor, including help from some of our eager students who wanted to place a couple of bricks on the walls!
Our goal for completing the project is June 1. We hope to fire the kiln for the first time shortly after that.
See also our photo essay on building the kiln.