smesa Posted March 18, 2021 Report Share Posted March 18, 2021 I’ve been working with earthenware up until now and using the same kiln always. Always have needed a cone hotter in the sitter to match the maturity points of my witness cones. Never an issue! I decided to give stoneware a try, bisquing at the same temp (cone 04) and firing at cone 6. Using the same technique of 1 cone hotter in the sitter to match witness cones. My bisque witness cones didn’t act as they usually do! None bent. 05 was just staaarting to move. And my glaze fire witness cones at cone 6 did not bend either, with a cone 7 in the sitter. Does the change in clay change the way my kiln operates? Do I need another cone hotter (as in two cones hotter) in the sitter now? Any other ideas? Link to comment Share on other sites More sharing options...
Bill Kielb Posted March 18, 2021 Report Share Posted March 18, 2021 16 minutes ago, smesa said: Does the change in clay change the way my kiln operates? Do I need another cone hotter (as in two cones hotter) in the sitter now? Any other ideas? Could be your elements are wearing. The clay will make no difference other than If you are now producing more and filling the kiln more fully which I am guessing is unlikely but occasionally I get tripped up when they say they are making plates now so in reality a bunch more mass is going in the kiln. I would make sure your elements are fine, less than 10% increase in resistance from new. A few cone 6 firings will wear them far more than many cone 04. After putting the kiln in like new shape I would calibrate the sitter to finish at cone and as your elements wear you could then go up a cone knowing that element replacement is in the near future. Link to comment Share on other sites More sharing options...
oldlady Posted March 18, 2021 Report Share Posted March 18, 2021 once you have all that done, try using a bar in the sitter, not a tapered cone. for cone 6 you would use a cone 6 bar. Link to comment Share on other sites More sharing options...
smesa Posted March 18, 2021 Author Report Share Posted March 18, 2021 1 hour ago, smesa said: I’ve been working with earthenware up until now and using the same kiln always. Always have needed a cone hotter in the sitter to match the maturity points of my witness cones. Never an issue! I decided to give stoneware a try, bisquing at the same temp (cone 04) and firing at cone 6. Using the same technique of 1 cone hotter in the sitter to match witness cones. My bisque witness cones didn’t act as they usually do! None bent. 05 was just staaarting to move. And my glaze fire witness cones at cone 6 did not bend either, with a cone 7 in the sitter. Does the change in clay change the way my kiln operates? Do I need another cone hotter (as in two cones hotter) in the sitter now? Any other ideas? Link to comment Share on other sites More sharing options...
smesa Posted March 18, 2021 Author Report Share Posted March 18, 2021 1 hour ago, Bill Kielb said: Could be your elements are wearing. The clay will make no difference other than If you are now producing more and filling the kiln more fully which I am guessing is unlikely but occasionally I get tripped up when they say they are making plates now so in reality a bunch more mass is going in the kiln. I would make sure your elements are fine, less than 10% increase in resistance from new. A few cone 6 firings will wear them far more than many cone 04. After putting the kiln in like new shape I would calibrate the sitter to finish at cone and as your elements wear you could then go up a cone knowing that element replacement is in the near future. Thank you! I will give that a go must find a tech now..! Link to comment Share on other sites More sharing options...
Callie Beller Diesel Posted March 18, 2021 Report Share Posted March 18, 2021 Handy reference on how to calibrate a cone sitter: https://suemcleodceramics.com/how-to-calibrate-your-kiln-sitter-for-accurate-firings/ Link to comment Share on other sites More sharing options...
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