Soda Firing #2
One month and three days after firing #1, I was back in the frigid kiln yard with a space heater and a bucket of hot water, filling the soda kiln up once again. This time with a more grounded sense of confidence having actually been through the process once before, and also with a heap of excitement for the new work. I also had a new and improved game plan based on the successes and failures from the month before. Let's do this.
This time around I made pots with my 4 favorite clay bodies from the tests that came out of firing #1. I knew that this firing would yield much different results from the 1st, but I still figured it would be a good idea to build off of the first firing's results. I also made another batch of clay tests playing with the recipes of those from the first.
I'm sharing the details of my load so that those of you who also fire soda kilns can compare and contrast with the way that you stack a kiln. I'm always interested in seeing/talking about your strategies as well, so please reach out if you have anything you'd like to ask/share!
Okay, so now the fun part...
Firing #2 Details:
Directly from my notebook...
"My biggest issue with this firing was the huge cone disparity. I believe it was mostly due to cranking the gas too high, too quickly when I came in in the morning. Next time, gradual turn-ups. The pots all looked great. The ash glazes need to be hotter than soft 9, although, the nuka was nice, and white, and dry/matte at that temp. Maybe not great for a plate surface, though. Didn't worry much about body redux. Surfaces were very rich. Immediately sealing the damper seems to be okay. Only very minor blistering. This process seems to be hard on the furniture. Definitely moving in the right direction!"
As stated, this firing was quite uneven. Probably cone 12 in the hot spot, and 8/soft 9 in the cool spot. This obviously isn't an ideal circumstance, but it is great for learning. I found that contrary to my previous belief, clay colors in the hot areas were still very good, including bright reds and oranges. Hotter temps are certainly harder to achieve, but in terms of the work and what I am striving for, I think it is well worth it.
The full downfiring made a huge difference from the first go around. My stoneware body was red and purple instead of brown. Red and orange flashing on the porcelain was deeper and more vibrant. Carbon trapping was good, and only very minimal puckered/sugary surfaces that would be considered "seconds".
One thing I was very curious about after this firing was the importance of the body reduction. My reduction was very minimal with this firing and yet I still had a wide range of beautiful color. I wonder what would happen if I skipped body reduction completely?
Notes for the next firing:
-Don't turn up so fast!
-Skip body reduction
-Tighter stack (to even out temp)
-Re-oxidize with burner for 1 hour after downfire.
Thank you for reading! Please reach out with any questions/comments you may have about this stuff!
Thank you for sharing! Like you said, packing tighter will help even the heat out. I fire a downdraft soda built by Ted and had this same problem. 12 bottom 9-10 on top. Packing tighter on the bottom has gotten it basically completely even.
4/2/2020 01:48:27 pm
Hi Clayton! Thanks so much for reading. Your Ted kiln is a downdraught, and not a cross-draught, correct? My third firing was quite even, but I didn't necessarily pack the bottom any tighter. I was tighter up in the arch, though.
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