These are some of the pots that came out of the latest wood firing in the Manabigama at the University of North Dakota. I was excited to see the results as we chose to do a few things differently this firing, single firing most of the work but also changing how tightly the kiln was packed.
Previously we had used shelves from through the whole kiln, squeezing larger pieces into the front or between the stacks of shelves. This time we left the whole front half of the kiln free to fill with larger pieces, with the obvious result of better ash distribution.
For those that don't know anything about the Manabigama, designed and built by John Theis and Bill Van Guilder, it has an incredible amount of draw and can hit cone 13 really fast (in as few as eight hours). Having fired it a number of times with a hard cone 13 in front and as low as a cone 8 in the back, we started looking at ways to keep an even temperature throughout the firing but also slow the firing down to develop more ash.
To achieve this, we put four bricks into the exit flues and opened only four to eight of the primary air holes throughout the various stages of firing... relatively few considering the twenty that are able to be opened up. The firing ended up being sixteen hours (with a four hour preheat) and fired up to temperature nearly evenly the whole time, reaching between a cone 10 to cone 11. We are finally starting to utilize all the variables of the kiln and it is a real pleasure to fire as a student, especially as I see these kilns popping up all over the country.