sfinster Posted April 15, 2016 Report Share Posted April 15, 2016 I just replaced the elements in an old (1991) Skutt 1027 kiln. I loaded with shelves for the test firing, putting self-supporting ^04 cones at the bottom, middle, and top, and using a junior ^04 in the kiln sitter. All switches 1h low, 1h medium, then all to high. The switch dropped after 3 hours. The next day when I opened it up I found that the top and bottom witness cones weren't really bent at all, the middle witness cone was bent about halfway, and the sitter cone was overfired into a U. I should mention that I had the downdraft fan running the whole time. Not sure how to proceed. I was considering loading a bisque, spending more time on low and/or medium, and leaving the center ring on medium when I switch the top & bottom to high. I figure the worst that can happen is that I have to bisque things again. Anyone have any helpful suggestions? Thanks in advance. Link to comment Share on other sites More sharing options...
Min Posted April 15, 2016 Report Share Posted April 15, 2016 How are you loading the bisque? Is there a lot more mass in one section(s)? 5 hours if pretty fast if the kiln was really packed or if the clay has a lot of impurities to burn out. Link to comment Share on other sites More sharing options...
sfinster Posted April 15, 2016 Author Report Share Posted April 15, 2016 How are you loading the bisque? Is there a lot more mass in one section(s)? 5 hours if pretty fast if the kiln was really packed or if the clay has a lot of impurities to burn out. The first test firing is empty. Just shelves and posts, no work. Link to comment Share on other sites More sharing options...
Dick White Posted April 15, 2016 Report Share Posted April 15, 2016 1. That the sitter cone was bent to a U means the sitter is out of adjustment. The sitter should drop when the cone is bent to 90deg. Get a sitter calibration disk and adjust the claw and drop plate correctly. 2. That you got some wonky results with an empty kiln is normal. That you fired the new elements to bisque temperature with an empty kiln is the best thing you could have done. New elements need to be fired in a completely clean atmosphere to set a protective coating of oxidation on them. The atmosphere in a loaded kiln is pretty corrosive, and the initial protective oxidation will help them last longer. Now load some greenware and fire it again, but this time with a full set of witness cones, i.e., one cone above and one cone below your target. Then you will know more precisely whether a ring is over or under firing and by how much, and can adjust for it. Link to comment Share on other sites More sharing options...
ronfire Posted April 15, 2016 Report Share Posted April 15, 2016 When I adjust the sitter I use the guide plate and a feeler gauge. Find usually .016 works. If I need to change the setting I then use a thick or thinner gauge to make the change. Will adjust the sitter for the glaze fire, if a bisque is out ½ to 1 cone temp is not to critical. Also I find using bars more consistent than cones in the sitter. Link to comment Share on other sites More sharing options...
Min Posted April 15, 2016 Report Share Posted April 15, 2016 How are you loading the bisque? Is there a lot more mass in one section(s)? 5 hours if pretty fast if the kiln was really packed or if the clay has a lot of impurities to burn out. The first test firing is empty. Just shelves and posts, no work. sorry, misread your question. Link to comment Share on other sites More sharing options...
sfinster Posted August 14, 2016 Author Report Share Posted August 14, 2016 Update - I have done several bisque and 2 ^6 glaze firings since this post. I am getting better results with a full load and very slow firing. Witness cones show that I'm getting above ^5, not quite to ^6. I'm going to go with it. Link to comment Share on other sites More sharing options...
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