Bam2015 Posted August 31, 2022 Report Share Posted August 31, 2022 I feel a bit stupid asking this question, but here goes. Does a kiln go through a cooling down program after firing or does it just switch off? Betty Quote Link to comment Share on other sites More sharing options...
neilestrick Posted August 31, 2022 Report Share Posted August 31, 2022 In a typical firing, yes, it gets to temp and then turns off. Some people will program the kiln to cool at a specific rate, though, which we refer to as 'slow cooling'. Slow cooling can be used to change how glazes look, because more crystal growth happens as the cooling is slowed. This can result in better color development or changes in the surface of the glaze (matte, shiny, etc.). Another reason for a controlled cooling cycle is to achieve the same results from different kilns. For instance, I have 3 kilns- a 10 cubic foot model, a 4 cubic foot model, and a -1 cubic foot test kiln. They all cool at very different rates, and some of my glazes will look different depending on which kiln they're fired in. By using the same programmed cooling rate in all 3 kilns, I get the same results regardless of which kiln I use. Rae Reich and Hulk 2 Quote Link to comment Share on other sites More sharing options...
Bam2015 Posted September 1, 2022 Author Report Share Posted September 1, 2022 Thanks Neil. That's what I assumed but last time I did a glaze fire, most of my little porcelain bowls cracked on the bottom and I had shut my kiln switch off after the firing was complete. So I was wondering if I made the kiln cool too quickly and that caused the cracks. I've used porcelain in the past without this problem. This time I dried them pretty quickly, I treated them like stoneware, so maybe that was the problem. Betty Quote Link to comment Share on other sites More sharing options...
neilestrick Posted September 1, 2022 Report Share Posted September 1, 2022 49 minutes ago, Bam2015 said: Thanks Neil. That's what I assumed but last time I did a glaze fire, most of my little porcelain bowls cracked on the bottom and I had shut my kiln switch off after the firing was complete. So I was wondering if I made the kiln cool too quickly and that caused the cracks. I've used porcelain in the past without this problem. This time I dried them pretty quickly, I treated them like stoneware, so maybe that was the problem. Betty I wouldn't expect the cooling to be a problem with little bowls. Chances are they were already cracked or stressed before the firing. Can you post a picture of the cracks? Quote Link to comment Share on other sites More sharing options...
Bam2015 Posted September 1, 2022 Author Report Share Posted September 1, 2022 Neil, I already tossed them. But thank you for offering to take a look at them. Betty Quote Link to comment Share on other sites More sharing options...
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