nancysmith Posted October 30, 2018 Report Share Posted October 30, 2018 I have a small electric kiln that I've test fired. I'm very new firing kilns.... Cone 6 in the ASD Cones 5,6 and 7 for witness cones. One set on the bottom shelf in front of the peephole and the other set on the top shelf in front of the peephole. Safety timer switch turned to 20 Switch set for high fire Kiln turned on, the ASD cone 6 tripped it off, the safety timer switch had 1 hour left on the dial Kiln turned off and cooled After opening the kiln (it was an empty kiln because I was test firing) the top set of witness cones were fine, cone 5 overtired, cone 6 good, cone 7 underfired. The bottom set of witness cones only turned white and standing straight, no bend at all???? Why would this be? Something I did wrong? Nanc Link to comment Share on other sites More sharing options...
Arnold Howard Posted October 30, 2018 Report Share Posted October 30, 2018 Were the cones placed directly on the floor of the kiln? This would explain why the bottom cones are underfired. The floor of the kiln is difficult to heat, because the floor is a heavy thermal mass that requires a lot more energy to heat than the center of the kiln. Arnold Howard ahoward@paragonweb.com Link to comment Share on other sites More sharing options...
neilestrick Posted October 30, 2018 Report Share Posted October 30, 2018 So 19 hours? That seems mighty long. What brand and model of kiln is it? Link to comment Share on other sites More sharing options...
nancysmith Posted October 30, 2018 Author Report Share Posted October 30, 2018 5 hours ago, Arnold Howard said: Were the cones placed directly on the floor of the kiln? This would explain why the bottom cones are underfired. The floor of the kiln is difficult to heat, because the floor is a heavy thermal mass that requires a lot more energy to heat than the center of the kiln. Arnold Howard ahoward@paragonweb.com The cones were on the bottom shelf about 1" off the bottom base of the kiln So when the kiln is full of pieces to fire, what happens to the ones on the bottom shelf, compared to those in the middle and top?? Link to comment Share on other sites More sharing options...
nancysmith Posted October 30, 2018 Author Report Share Posted October 30, 2018 5 hours ago, neilestrick said: So 19 hours? That seems mighty long. What brand and model of kiln is it? It's a Duncan kiln The teacher model DA 820-2 Link to comment Share on other sites More sharing options...
neilestrick Posted October 31, 2018 Report Share Posted October 31, 2018 @nancysmith I'm wondering if all your elements are working. A small kiln like that should have plenty of power. Turn it on high for a few minutes and see if all the elements glow. Just carefully crack the lid and take a peek inside with the room lights off. Also check the serial plate and see what the max temp is. Could be that you're maxing it out, and the elements are a little worn so it's having a hard time getting to temp. A kiln that's rated for cone 6 really isn't good for firing to cone 6. Link to comment Share on other sites More sharing options...
nancysmith Posted November 1, 2018 Author Report Share Posted November 1, 2018 I will check the elements for sure!! When you say a cone 6 kiln doesn't fire to cone 6....because this is so new to me....will I be firing to cone 5? And using cone 6 clay? Link to comment Share on other sites More sharing options...
neilestrick Posted November 2, 2018 Report Share Posted November 2, 2018 5 hours ago, nancysmith said: I will check the elements for sure!! When you say a cone 6 kiln doesn't fire to cone 6....because this is so new to me....will I be firing to cone 5? And using cone 6 clay? I mean that a kiln will only get to its peak working temperature if the elements are in perfect condition. As soon as they age a little bit, they don't have the power to get there any more. Ideally you want to fire 3-4 cones below the peak temp. That way the elements can wear a while before they need to be replaced. It's the difference between getting only 50 firings out of a set of elements instead of 150. Link to comment Share on other sites More sharing options...
nancysmith Posted November 7, 2018 Author Report Share Posted November 7, 2018 Thank you so much for your help! Link to comment Share on other sites More sharing options...
nancysmith Posted November 7, 2018 Author Report Share Posted November 7, 2018 I just turned on the kiln for a few minutes, cracked the lid and all elements were red. The max temp is 2300. Also there's an automatic dial which I used for my test fires, or manual low and manual high. Link to comment Share on other sites More sharing options...
Mark C. Posted November 7, 2018 Report Share Posted November 7, 2018 Kiln fire differently with no load in them. You need the thermal mass to find out how it really will work . I read your kiln specs online and it should do cone 6 as its rated to cone 8. 19 hours is way to long for a fire. I suggest firing a real load of pots and put cone all over to see whats going on. Link to comment Share on other sites More sharing options...
nancysmith Posted November 8, 2018 Author Report Share Posted November 8, 2018 Thanks! So should I fire glazed pots or Just a bisque? Link to comment Share on other sites More sharing options...
neilestrick Posted November 8, 2018 Report Share Posted November 8, 2018 If it won't reach temp empty, it won't do it full either, and you run the risk of ruining a lot of glaze work. No sense loading it up with work until you know for sure it works. Try another cone 6 on manual high and see if it does any better. It could be that the automatic setting it ramping it up too slowly. Link to comment Share on other sites More sharing options...
Mark C. Posted November 8, 2018 Report Share Posted November 8, 2018 You could put a few bricks or posts in the load to create some mass. Link to comment Share on other sites More sharing options...
nancysmith Posted November 8, 2018 Author Report Share Posted November 8, 2018 Thankyou, I will try manual high Link to comment Share on other sites More sharing options...
nancysmith Posted November 10, 2018 Author Report Share Posted November 10, 2018 Should the 2 peep holes be open or closed? The hood of the kiln also has a small vent hole. Link to comment Share on other sites More sharing options...
neilestrick Posted November 10, 2018 Report Share Posted November 10, 2018 If you're using a downdraft kiln vent, close all the peeps. If not, keep the upper wall peep open. Link to comment Share on other sites More sharing options...
nancysmith Posted November 12, 2018 Author Report Share Posted November 12, 2018 Neil, You're saying to try closing the bottom peep and leave the top peep open? I don't have a vent as of yet, the kiln is in a room w window off our garage. Link to comment Share on other sites More sharing options...
neilestrick Posted November 12, 2018 Report Share Posted November 12, 2018 Just one peep open, the upper peep in the wall. Link to comment Share on other sites More sharing options...
nancysmith Posted November 15, 2018 Author Report Share Posted November 15, 2018 Thank you Neil!!! Link to comment Share on other sites More sharing options...
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