It has been two years since I last fired in a wood fueled kiln (see sample pot at bottom of this post). In the interim, I have been firing in electric and working on my cone 6 (around 2200 degrees F) glazes. Occasionally, I would throw a pot into the gas kiln. But mostly I have stuck with what was predictable. I haven’t been interested in the unpredictability of a wood kiln.
But then I went to Italy and fired in a soda kiln. This particular kiln was fired with liquid propane gas to a temperature of around 2377 degrees F. Then toward the end of the firing, we introduced soda (in the form of sodium bicarbonate) to the kiln which gave a wonderful luster to our pots and activated the flashing agents in our slips as you can see from this piece below. The orange color is uneven from where the flame and soda interacted with the pot surface. The grey deposits are where the soda built up on the pot.
The results that come out of a soda kiln, or any kiln where you are using the kiln atmosphere to achieve a specific result, are beautiful and unpredictable. Soda is not the only atmosphere additive. Potters will also add salt to a kiln, which can yield a surface texture similar to an orange. Still others simply fire with wood and let the flying ash land on the pots in the kiln, creating wonderful patterns and textures.
I think of atmospheric kilns like playing golf. You get one great pot out of an atmospheric kiln (like that one great drive or putt), and you keep coming back for more trying to replicate that pot (or shot). But like my experimentation with golf, I took a hiatus from atmospheric firing. While I liked the results from the wood firing in 2007, the process requires a lot of work and I was making so little work at that time that I was not willing to commit to a process with such variable results. But my experience with soda firing in Italy hooked me again. I had to go back for more. The unpredictability was now an enticement, not a source of frustration.
The Washington D.C. metro area doesn’t have a lot of soda firing occurring, but salt and wood kilns are relatively plentiful. One of the great resources we have in this area is Baltimore Clay Works. BWC has a two chambered wood fueled kiln, one of which they add salt to (and sometimes soda) at the end of the firing. Next Friday I will be glazing and loading several of my pots into 1/5th of the BWC’s kiln. We will be firing starting Saturday morning and finish up Sunday morning. We will unload the kiln the following Wednesday.
Because I haven’t fired in this kiln, I am trying to maximize the amount of information I get out of it, without going crazy. I am using four different clay bodies: Laguna’s B-mix, Standard 306 brown stoneware, Standard Trina Buff white stoneware and Standard 213 porcelain. I have two atmospheres to work with: salt and wood. While I have numerous glaze possibilities, I have decided to limit myself to three: yellow salt, oribe and golden shino. A few weeks ago, I sat on my living room floor with a large sheet of paper and divided it by four (for each clay body), divided those spaces by two (for each chamber), and then again by three (for each glaze). My studio colleagues chuckled at me for my methodical approach, but I look forward to seeing each of the twenty-four possibilities that will come out of the kiln in early November.
As much work as just preparing for this firing has been, I am excited to be going back to atmospheric firing. If all goes well, I hope to fire in such a kiln two to three times per year, creating a high fired line of my altered work. I am also excited to be sharing the experience with you. Assuming I will have internet access next weekend, I hope to post pictures from Friday’s glazing, wadding and loading day by Saturday morning and then pics of the actual firing by Sunday. Then the unloading and results by November 6th. Stayed tuned.