I just emptied the kiln from my latest glaze firing. I've been hesitant to do a glaze firing because the last one I did was terribly unsuccessful. The chun glaze came out whitish/cream colored and totally blistered. The other glazes were blistered as well but not nearly as badly. I realized that I had kind of rushed the firing - not waiting a full hour between turning the switches on. In fact none of the witness cones (4, 5, and 6) even bent. So this time I waited a full hour and even an hour and 10 minutes on the last 3 switches. I put the chun pieces back in hoping they might cure properly, to no avail. The chun glaze actually flaked off to some extent. The other glazes, mostly royal blue which has always been the most stable glaze one could ask for, even blistered. I noticed it had done that previously but mostly when using porcelain clay.
The first few times I fired, pieces came out nicely, especially the royal blue. I don't know why it's changed. So now I'm Googling and trying to figure out what the problem might be.
fiorghra - a place for my ramblings about pottery, kayaking, poetry, and life in general, for me to look back on when I'm old and feeble.
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Follow up: I spoke to Malley while at Hattie's the other night. She said the first bad firing was probably due to too low a temperature and the second was due to too high a temperature. So I need to put a Cone 5 in the peep hole and use that to determine when I get to the proper temp. Period. Will give it a try.
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