We fired our test tiles at Claymakers today. There was a bit of a drizzle early in the day, but it got better by noon. Still chilly though. The tile above was the best of the three. It was fired to 1500 degrees.We fired first to 1450, second firing was 1500 and the third firing was 1550. At 1500 the underglazes held and the cobalt started to settle out. All three firings gave great copper(upper left hand squares) with really good crackle.
At 1450 the underglazes all flaked off though held some color but powdery and rubbed off easily. Might be good for naked raku.
At 1550 the underglazes flaked off and no color held.
Good crackle at all three temps for this copper carb
Cobalt didn't melt until the highest temp
All in all some great success with low fire possibilities. Next week we will meet and look at everyone's tiles and make some final conclusions. I'll get more photos of everyone else's tiles and post next week. I'm really excited about this. Each firing took less than one hour from start to finish. We started at 9am and I was leaving the studio at 2pm with everything cleaned up and put away. Pretty efficient! And a great group of potters to work with. I took lots of great photos but left the dang card for my camera at home and discovered this too late to do anything about it. I'll get some pictures of the firing we do when we apply glazes to actual pieces!