GEP Posted August 21, 2016 Report Share Posted August 21, 2016 I think one of my top zone elements just failed. My elements were approaching their life span, and there was one spot on my second-to-top element that looked more worn than everything else. This morning I found my kiln was still firing after 12 hours, when it usually takes 9. The top zone was way behind, and the ramp was climbing at roughly 30°/hour. Normal program is 120°/hour for the final segment. I looked at a cone chart, and the closest the data I could find for my situation was: cone 5 at 27°/hour is 2118 cone 5 at 108°/hour is 2167 This is pretty close to the ramp I was getting vs the one I'm used to. The difference between then is 49°. My final temp was supposed to be 2180°. So I subtracted 50 and shut the kiln off at 2130°. Does anyone have any sense that I did the right thing? If not, it's ok, I'll find out tomorrow morning when I open the kiln. If the top shelf or two is underfired, while the rest of it is ok, I'll consider that a victory. Link to comment Share on other sites More sharing options...
Marcia Selsor Posted August 21, 2016 Report Share Posted August 21, 2016 Be sure to tell us how it went. Marcia Link to comment Share on other sites More sharing options...
Joseph Fireborn Posted August 21, 2016 Report Share Posted August 21, 2016 Best of luck. I had a test kiln that couldn't reach temp. The first time I fired it, it slowly climbed from 2050F to 2100F(and stalled here) around the same rate your talking I estimated about 2-3 hours between those temps. I eventually got tired of watching it stall and turned it off. I reached cone 5. The glazes looked a little bit different though. Let us know how it goes. Link to comment Share on other sites More sharing options...
glazenerd Posted August 21, 2016 Report Share Posted August 21, 2016 GEP: I would assume 2180 with a ramp hold? If that is the case, how long did it stall at 2130? Long enough to jump a cone in heat work? How sensitive is the glaze? Will it tolerate a variance in cone and still melt? Nerd Link to comment Share on other sites More sharing options...
GEP Posted August 21, 2016 Author Report Share Posted August 21, 2016 It didn't stall at 2130. I found it at 2050 and still climbing at about 30°/hour. So I shut it off when it hit 2130. My liner glaze will melt at a lower temp, but my main semi matte glaze has a much smaller tolerance. Mostly, I didn't want to OVERfire. Last time this happened (maybe 6 yrs ago), I let the kiln finish to final temp and it was all overfired. If it's UNDERfired, I can refire. My glazes will look slightly different, but only enough for me to notice. Link to comment Share on other sites More sharing options...
oldlady Posted August 22, 2016 Report Share Posted August 22, 2016 sorry, mea. busy season is no time to need rewiring. hope it works out well. wish there were a way to tell when things will go wrong before turning on the kiln. i have a single element with a slight bit of lean to the right. it is in the center of the kiln and i hope it will last the season. going to fire this week. Link to comment Share on other sites More sharing options...
glazenerd Posted August 22, 2016 Report Share Posted August 22, 2016 GEP: Got it now: would think you have a very high chance of an under-fire. Nerd Link to comment Share on other sites More sharing options...
Marcia Selsor Posted August 22, 2016 Report Share Posted August 22, 2016 How were the results? Marcia Link to comment Share on other sites More sharing options...
GEP Posted August 22, 2016 Author Report Share Posted August 22, 2016 So far I've only looked at the top shelf. It's cooling very slowly. Ok I admit this load was very dense, six shelves of flat pieces. Not a nice thing to do to old elements. The liner glaze looks good but the semi-matte looks dry. Didn't pick anything up to inspect closer, still too hot. I'll know more in a few hours. Thanks for asking! Link to comment Share on other sites More sharing options...
GEP Posted August 22, 2016 Author Report Share Posted August 22, 2016 Here's the report. The top 3 shelves were very underfired. I'm actually impressed that my liner glaze still worked, I've never fired it this low before. Shelves 4 thru 6 were pretty close to being normal. I'm going to try to refire them anyways, because they still have some dry areas that don't feel good to the touch. I think one of the selling points of my pots is that they feel good to the touch. I will put a few of these pots in my next glaze load, which will have to be tomorrow now that I've only got one kiln right now. If they come out fine, then I'll refire the rest. I have refired underfired pots before, without any problems. Knock on wood. New elements and TCs have been ordered. So it wasn't what I was hoping for, but it's also not the worst thing either. Thanks for all the nice responses! Link to comment Share on other sites More sharing options...
oldlady Posted August 22, 2016 Report Share Posted August 22, 2016 good! Link to comment Share on other sites More sharing options...
No Longer Member Posted August 24, 2016 Report Share Posted August 24, 2016 What kiln do you have? A little time testing elements with a DVOM goes a long way IMO. I save all of our changed out elements to be matched up later by resistance for my Frankenstein junk kiln builds made from free stuff. Link to comment Share on other sites More sharing options...
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