sbrew Posted May 19, 2014 Report Share Posted May 19, 2014 This is my first time asking a question but ive often found answers o my questions on these boards... I've used kiln sitters before, years ago, and never once had problems until a bisque firing last night. I've noticed that it's been taking a bit longer to reach cone 04 in bisque and cone 6 in my glaze firings, my bisque last night took about 9 hours before I manually shut the kiln off. I could tell the sitter was close to shutting off, and I wanted to get some sleep. When I opened the kiln after cooling, the cone had bent, but it has this big bubbly blob in the bend. The bisque looks fine, but I've never seen a cone do this.. I have a small paragon s1193 kiln, and most of the firings have been perfect until the recent slowing down of the firings and this cone mishap. I've been using it since late January of this year.. I attached a pic of the cone 04, to see if anyone else has had this issue... Thanks! Link to comment Share on other sites More sharing options...
sbrew Posted May 19, 2014 Author Report Share Posted May 19, 2014 Pic didn't work the first time! Link to comment Share on other sites More sharing options...
mregecko Posted May 19, 2014 Report Share Posted May 19, 2014 Weird. Could it have overfired significantly? Looks almost like clay bloating. Alternate theory, could it have gotten something in / on it? Soaked in some odd chemical, water, some sort of oxide on it, etc? Link to comment Share on other sites More sharing options...
sbrew Posted May 19, 2014 Author Report Share Posted May 19, 2014 Not that I'm aware of, I keep the cones in their box in a Tupperware container so I don't accidentally get glaze or anything on them. I would usually say it overfired, but then why wouldn't the sitter have shut itself off? Link to comment Share on other sites More sharing options...
Mark C. Posted May 19, 2014 Report Share Posted May 19, 2014 I have few questions is this a small cone or bar? any chance they got wet ever? was the sitter rod close to a shelve?could have expanded into the sitter?or a clay piece? It does look overfired and bloated so my guess is overfiring Did you have a test cone (larger in load to know the end temp? If the answer is not than get some for next fire. Mark Link to comment Share on other sites More sharing options...
Arnold Howard Posted May 19, 2014 Report Share Posted May 19, 2014 I've seen a cone bloat like the one in your picture. However, it bloated because it was fired very rapidly. It was a self-supporting cone that bloated and distorted so severely that it couldn't bend. I had fired it to about 1300F in 15 minutes as an experiment. I think your defective cone is a fluke and probably the only bad one in the batch. Sincerely, Arnold Howard Paragon Industries, L.P., Mesquite, Texas USA ahoward@paragonweb.com / www.paragonweb.com Link to comment Share on other sites More sharing options...
williamt Posted May 20, 2014 Report Share Posted May 20, 2014 On the issue of longer fire times, how old are the elements in your kiln? or how many firings at cone 6? I had a couple of over firings because the kiln was taking too long to get to temp and too much heat work occurred. I'm currently changing elements! The cone does look bloated. Link to comment Share on other sites More sharing options...
Min Posted May 20, 2014 Report Share Posted May 20, 2014 How about contacting Orton and attach a pic with the bloated cone? http://www.ortonceramic.com/contact-us/ Link to comment Share on other sites More sharing options...
Pres Posted May 20, 2014 Report Share Posted May 20, 2014 Years ago, I had a kiln that had the setter mounted over two sections. No big deal until I overfired a load. I had the timer usually set 30 min longer than what a load would take, so not a major overfire, but significant. I checked everything out, and found that the cone had melted-slumped. I also found the setter rod was in the valley of the cone. However, because the two sections got out of alignment the setter trigger would not fall. Make certain to check everything out with the setter to make certain everything that is supposed to happen with it does. Link to comment Share on other sites More sharing options...
Babs Posted May 20, 2014 Report Share Posted May 20, 2014 I agree I have had cones do this in one kiln which when turned onto the highest input roared away like a freight train. The cone would bloat and melt and in so doing fix the kiln sitter needle in such a way that it would not turn off Link to comment Share on other sites More sharing options...
neilestrick Posted May 20, 2014 Report Share Posted May 20, 2014 I've only seen cones do that because they got wet at some point. Link to comment Share on other sites More sharing options...
Wyndham Posted May 21, 2014 Report Share Posted May 21, 2014 I've had sitter cone fuse and over fire. Seems that the kiln sitter drop bar didn't drop in time and the cone fused holding the kiln sitter rod from moving. Check to see if the drop bar has any debris. Wyndham Link to comment Share on other sites More sharing options...
Babs Posted May 22, 2014 Report Share Posted May 22, 2014 Yes, can't say about the wetness as I stopped firing that kiln on high and stopeed firing to that cone almost simultaneously. Coukd have been a damp box or cone. i do from time to time readjust the pin in the sitter by inserting the gauge, through time the sitter needle does change in diameter which alters what happens. Link to comment Share on other sites More sharing options...
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