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Showing results for tags 'diy kiln controller'.
Hi, I would like to share my Kiln built and ask for some insights as my experience with Kiln were all in studios where others were operating it and I did not follow the whole firing cycle. I believe it is important to start saying that I was not sure if I should post it here or at "Equipment Use and Repair", please let me know. I will try to convert the metric information to imperial, but i may fail, apologies in advance. I decided to make a small kiln from K28 bricks (1530C / 2800F), the bricks are 65mm(2 1/2"). The bricks lay inside a metal drum, with a thin layer of ceramic insulation blanket, in order to reduce the gap between brick and metal, and try to add a bit more insulation; It is a Dihedral (new word on my vocabulary, twelve-sided polygon), and ~300mm (11 1/2"?) height, and ~300mm (11 1/2"?) "diameter", resulting in ~20L or 0.7ft3 From commercial Kiln, I found that 20L takes 2300W, threfore using an Europe power plug (230V and 13Amps): I used Kanthal A1 wire (1mm, AWG 18) aiming for 23Ohms, ie. ~12.5m (41ft).; I coiled the element around a 6mm (1/4"?), resulting in a Surface load of 5.89W/cm2 (38W/in2) -> I know this is high, but I struggled to find a thicker wire, I will replace that in the future; The element above, also resulted in a coil pitch ("stretch factor") of 4x when using 3x layers of element inside the Kiln, again on the extreme side, it will be fixed with a thicker wire; I also built the controller myself, which I can share if people are curious. With the introduction out of the way, I did a test fire on the kiln yesterday, aiming for Cone 05 1/2 -> 1015C or 1839F, as a test, since my local ceramic shop only had this cone in stock and I would like to validate against the thermocouple, type K, readings. The Kiln had a bottom shelf, raised 1/2" from the floor; the self supporting cone was placed in the middle. The ambient temperature was -4C (25F) After 10hrs , it was late and the Kiln was really struggling to raise the temperature more than 870C (1600F), the temperature was going up, but Very Slowly as seen on the graph below. Therefore I concluded that it would take few more hour to reach the final temperature (if it was able to do so). The firing schedule, not very relevant I guess, was: 120C -> 110C/hr | 250F -> 120F/hr 538C -> 250C/hr | 1000F -> 400F/hr 120C -> 167C/hr | 1659F -> 300F/hr 1015C -> 60C/hr | 1839F -> 108F/hr Finally, my questions are: Does someone have a 2300W Kiln and can share some experiences with the firing Cycle? Do you see any absurd flaw that would justify the behavior? Some pictures: