Thursday, August 29, 2013

How to lose 5lbs in 1 day

I went to Medicine Hat last Wednesday to fire the Salt and Soda Kilns at the Shaw Centre at Medalta.
I left right after work on Wednesday afternoon and arrived at our motel at 7:30. Kathy and I got up early and went to glaze and load the kilns on Thursday and turned the kilns on low and slow overnight to preheat. There were various issues with this round of firing. The cone packs in the soda kiln blew up during the preheat, so we were flying a bit blind. Aaron found us an optical thermographer called the Cyclops. He was not sure how to use it, so had one of the train kiln operators from the old IXL brick factory to come over and trouble shoot it with us. As this was our only guide for temperature, we used it as well as colour in the kiln. By the time a witness cone bent in the salt kiln we had finished adding the soda, so that was pretty much a shot in the dark. We took a reading when cone 7 bent, and it looked like the “cyclops” was out by a hundred degrees or so. I think we were slightly underfired in the soda, but got some decent results. The salt was much better, although it could have used a bit more salt. In total, we added about 6 pounds of soda ash, and 14 pounds of salt. I did not take many pictures during the firing as it is too hard to do that when there are only 2 of us. If I could find a way to grow a 3rd arm, that would help. I would look weird though.
As to the weight loss, it was all sweat. The temp in Medicine Hat on the day of the firing was about 31 degrees Celsius (87.8 F). Without the kilns it was pretty darned hot out. The kilns themselves were at about 2385 F or so at top temp. We were a little limp with the heat by the end of the day. While we were waiting for the salt kiln to reach salting temp (it took until 9 pm or so), we ordered a pizza, around the time the pizza was to arrive, a torrential downpour sprang up. So we had heat, lightning, thunder, rain and pizza.
All in all I think the firings were OK. The soda was a bit dry in spots, but the salt was relatively juicy. There were some really nice glazes in this firing. I had some excellent carbon trapping in a Malcolm Davis shino, some good colour development in the yellow salt glaze, and some really lovely pink halos and blushing on the insides of some of my rice bowls where I used the Andrew Wong Lustre glaze. That glaze can come out quite boring and white if not reduced enough (?), but this time, I think we had good reduction. Not too much, just enough. 
Oh ya, I also saw the Medalta International Cup Show. The labels had not been put up yet, but I was able to recognize quite a few potters. There were several of Jim Gottuso's yunomis and beer glasses, a couple of cups from Zygote, a wall piece from Mindy Andrews and a ton of others that I just can't recall the makers of off the top of my head. There was stoneware, porcelain, low fire, high fire, salt, soda, functional and not so functional, etc etc...Very good show. Great job Carol for picking all of these amazing cups.

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