Bonnies Posted July 4, 2012 Report Share Posted July 4, 2012 So many questions on this topic but I'm hoping to find a direct answer to help understand my results:- I fired my new second hand J&J kiln last night for the first time, attempted heat was 06. This is an older model, with just a kiln sitter and no automation. I placed an 06 cone in the kiln sitter, and a bed of pyrometric cones to view through the peep hole - 07, 06, 05. After gradually ramping heat over 4 hours, and 3 + hrs on high, the kiln sitter shut off. I know that I should have probably placed an 05 in the sitter, as the heat near the kiln wall can be higher thus causing inaccuracy, however the pyrometric did not bend at all, not even the 07. Any tips or suggestions ? What can I assume about the firing and elements if the 07 witness cone did not bend, but the 06 in the sitter did? And can I assume that the bisqued work matured? THANKS! Link to comment Share on other sites More sharing options...
Marcia Selsor Posted July 4, 2012 Report Share Posted July 4, 2012 If the ^06 in the sitter shut off the kiln, then you should have an ok bisque. I think you may want to calibrate the setter for future firings. Was the ^06 bent just barely? The ^07 in you pack should have done something. How large is the kiln. Where were the cones in relationship to the sitter? Could you have an element out near to the location of the ^07? Marcia Link to comment Share on other sites More sharing options...
Bonnies Posted July 4, 2012 Author Report Share Posted July 4, 2012 If the ^06 in the sitter shut off the kiln, then you should have an ok bisque. I think you may want to calibrate the setter for future firings. Was the ^06 bent just barely? The ^07 in you pack should have done something. How large is the kiln. Where were the cones in relationship to the sitter? Could you have an element out near to the location of the ^07? Marcia Link to comment Share on other sites More sharing options...
Bonnies Posted July 4, 2012 Author Report Share Posted July 4, 2012 Hi Marcia, thanks for replying so fast, and on July 4th! What a pleasant surprise... To your questions: Yes, the ^06 was bent just barely and taking a look again at the ^07, really, hard to detect a change in angle at all. The kiln is a J&J 18, two rings so it's about 18 high by 17.5 wide. I didn't pack very much into the kiln (1 large tile per shelf), using 5 shelves in all. The cone bed was placed 1/3 inwards on the top shelf, so that I could view it from the top peep hole. I need to double check the bottom elements, maybe fire on high for 10-15 min to make sure they all glow up, but the element around the cone bed was definitely glowing. So far I can only see the tile on the top shelf which looks great, but I don't know how well it's matured... Any more thoughts and tips - EXTREMELY APPRECIATED! Especially as to what to check, and how to better plan next firing! Thanks, Bonnie Link to comment Share on other sites More sharing options...
Marcia Selsor Posted July 4, 2012 Report Share Posted July 4, 2012 I think 5 shelves in an 18" kiln is a lot of mass. You would probably need to fire longer. I scanned an old slide from my year of visiting potters in Spain. This is home made plate or tile setters. Little clay pegs are inserted into the holes in the columns. This would help eliminate a lot of mass and reduce the stress on your kiln.When you unload the kiln, check your elements. Link to comment Share on other sites More sharing options...
Bonnies Posted July 11, 2012 Author Report Share Posted July 11, 2012 HI Marcia, Did you see my message back to you today... I'm a newbie to this so I don't know where the messages are but I answered you this morning. In any rate, just did another firing, only 4 shelves this time, containing just 4 9"x9" tiles... Kiln worked for 8 hours - as I ramped up from low, medium, and then finally high which was around 3 of the 8 hours. Large cones don't appear to have bent - ^07; ^06; ^05. I'm assuming the sitter cone 06 bent slightly, turning it off... will be smarter tomorrow. Is it logical that there be a temperature difference between the small cones for the sitter - in my case ^06, which bends before a large ^07 cone in a cone bed? Also, while asking - how many hours after the kiln is finished is it ok to prompt the lid to help the cooling process? Thanks so much! Bonnie Link to comment Share on other sites More sharing options...
Marcia Selsor Posted July 11, 2012 Report Share Posted July 11, 2012 I usually wait til about 400 degrees F. With tiles I'd wait til it was cooler. maybe 300. Not good to rush cooling. Marcia Link to comment Share on other sites More sharing options...
Mark C. Posted July 11, 2012 Report Share Posted July 11, 2012 There are differences between large and small cones. Mark Link to comment Share on other sites More sharing options...
Bonnies Posted July 13, 2012 Author Report Share Posted July 13, 2012 There are differences between large and small cones. Mark I will try maybe making my cone bed with small cones, 05, 06 and 07, and see how that works. Thanks Link to comment Share on other sites More sharing options...
Bonnies Posted July 13, 2012 Author Report Share Posted July 13, 2012 I usually wait til about 400 degrees F. With tiles I'd wait til it was cooler. maybe 300. Not good to rush cooling. Marcia Thanks! Link to comment Share on other sites More sharing options...
Recommended Posts
Archived
This topic is now archived and is closed to further replies.