Do you know why something may explode in a bisque firing?
Well, I’m finding out as I try different things out. I had a piece that had a little moisture (still cool to the touch) when I put it in the kiln, and thought that would dry out safely with a slow firing setting. Well, it did not. Even at a slow setting, it was to fast for the moisture to safely leave the clay and the pressure made the piece explode. I asked some experts (with lots more experience than me!), and I found out that I should have used a ramp up method with a hold time period for the first two phases. The first ramp up should only increase 50 degrees Fahrenheit per hour until it reaches 180 degrees, then it should hold at that temperature for at least 12 hours. This is the perfect temperature to draw all the moisture out of the pieces to prevent any blow ups! The second ramp up phase takes the temperature to 360 degrees and if I want to be really careful, I should hold that temperature for 2 hours before ramp 3 and 4. I will be making those adjustmets for future bisque firings. Blowing up precious hours of work into pieces is not something I want to repeat regularly.