Kiln Problems

I'll give an update on the ceramics studio here. The students glazed all the lovely bisque ware that came out of the kiln, but when I did a glaze firing two weeks ago, the pieces came under-fired. We have been running the kiln in the old studio based on the electronic readings, but this time, the electronic review said the kiln had attained 2232 degrees, when it was obvious that many of the pots in the bottom of the kiln had not gotten anywhere close to that temperature. I ordered some standard Orton indicator cones, and we reran the glaze kiln with indicator cones at each blowhole. I started the kiln early last Thursday, and was able to monitor it's progress. The upper element did heat up, but the lower element initially didn't heat up at all. When the electronic read-out said the kiln had reached 1200 degrees, then the lower element came on and heated up very rapidly, causing a couple pieces on the bottom shelf to pop when the kiln reached around 1350 degrees. I heard them go. The next day, when the student worker unloaded the kiln, the indicator cones were not deformed at all. The kiln had not even heated up to Cone 4. This is very disappointing for the students, who are eager to see their finished work. It would appear that the electronics in the kiln are malfunctioning - the temperature sensor appears to be very mis-calibrated, and the programing that is supposed to turn the different elements on and regulate how much current is run to each element is also not working correctly. My supervisor is making arrangement to have someone from Runyon Clay, where the kiln was purchased, come down and work on it. This kiln is at least 10 years old, and is apparently damaged in the move from the old studio to the new - it just got shook up, I guess. Always something. Spring break is next week for our little college, so I am having the students do mini-critiques for their midterm grade. They will present me with their two best pieces, and we will evaluate concept, technique and product for each piece. This will be fun for me, but stressful for the students, I suppose.