Danny Posted May 27, 2020 Report Share Posted May 27, 2020 Hello me again. I have done a few glaze firing test in my kiln, test one reaching 1240, test 2 reaching 1222 and test 3 reaching 1220. But each time the cone 6 witness cones have over fired. The glazes have came out pretty good and I'm happy with them, afew colours burnt out. What could I be doing wrong? Link to comment Share on other sites More sharing options...
Min Posted May 27, 2020 Report Share Posted May 27, 2020 How quickly did the temperature rise during the final 1 1/2 - 2 hours? If your elements are getting old and worn the kiln can struggle to get to your target temp therefore the longer time spent getting there can amount to more heatwork and cause overfiring. Also, did you have a soak at the end of the firing? That too will cause more heatwork. Link to comment Share on other sites More sharing options...
Danny Posted May 27, 2020 Author Report Share Posted May 27, 2020 1083c to 1240 was 140mins 1081c to 1220 was 83mins 1100 to 1200 was 60 mins No I didn't have a soak time, I just let the kiln cool naturally when it reached max temperature My partner bought a small electrical muffle kiln new for Christmas, first time firing a kiln myself Link to comment Share on other sites More sharing options...
Min Posted May 27, 2020 Report Share Posted May 27, 2020 I'm not familiar with muffle kilns, were the cones quite close to the elements? Link to comment Share on other sites More sharing options...
Danny Posted May 27, 2020 Author Report Share Posted May 27, 2020 It was near the wall (maybe I should have put it in the centre) my kiln is very small. To be fair most of the glazes have come out well, with the odd burnt out I can't fit any work no bigger than 30cm tall or wide aha Link to comment Share on other sites More sharing options...
neilestrick Posted May 27, 2020 Report Share Posted May 27, 2020 You might need to calibrate your thermocouple. Link to comment Share on other sites More sharing options...
Bill Kielb Posted May 27, 2020 Report Share Posted May 27, 2020 2 hours ago, Danny said: 1083c to 1240 was 140mins 1081c to 1220 was 83mins 1100 to 1200 was 60 mins No I didn't have a soak time, I just let the kiln cool naturally when it reached max temperature My partner bought a small electrical muffle kiln new for Christmas, first time firing a kiln myself Move the cone away from the wall. Dial in a lessor temp as you go to find it for this kiln. Something is wrong with your segment programs though as they overlap the prior segments so hard to understand what is really going on here. So move the cone and build a program that is sequential. Make the final segment 1100 - 1200 @ 100c per hour though to start. Link to comment Share on other sites More sharing options...
Danny Posted May 27, 2020 Author Report Share Posted May 27, 2020 Thank you @neilestrick that's something to look in to. @Bill KielbKielb I'm probably doing the programs wrong. My last program I tested was 83 mins to reach 104c 278mins to reach 1100c 60mins to reach 1200c I'm not very good, the cones overfired but only the odd few glazes burnt out and the others looked good so it's confusing :/ I did see a program 5hrs to 600c- 2hrs50mins to 1222c and hold for 10 mins that I was maybe going to try Yes I will move the cones thank you Link to comment Share on other sites More sharing options...
Bill Kielb Posted May 27, 2020 Report Share Posted May 27, 2020 1 hour ago, Danny said: Thank you @neilestrick that's something to look in to. @Bill KielbKielb I'm probably doing the programs wrong. My last program I tested was 83 mins to reach 104c 278mins to reach 1100c 60mins to reach 1200c I'm not very good, the cones overfired but only the odd few glazes burnt out and the others looked good so it's confusing :/ I did see a program 5hrs to 600c- 2hrs50mins to 1222c and hold for 10 mins that I was maybe going to try Yes I will move the cones thank you Here is a popular one you can try (Been used for decades) 1. 60c/hr. To 120c 2. 200c/hr To 1080c 3. 100c/ hr To 1220c I am not sure what the hold at the end is doing but at this point only It’s helping to overfire this. So for now, no hold at the top until we really have a reason for it. Link to comment Share on other sites More sharing options...
Danny Posted May 28, 2020 Author Report Share Posted May 28, 2020 I will give this one a try later on today, hopefully the cones will look abit better and I can adjust from there This may be a silly question, but if the cone 6 pyrometric cone bent fully (overfired) does that mean the work went to a cone 7? I only put 4,5,6 pyrometric cones in because that was recommended before. Link to comment Share on other sites More sharing options...
liambesaw Posted May 28, 2020 Report Share Posted May 28, 2020 Cones can go from perfect cone 6 to completely slumped within a few degrees according to Orton. So I wouldn't bet on it, although cone 6 and 7 are fairly close. Link to comment Share on other sites More sharing options...
Danny Posted May 28, 2020 Author Report Share Posted May 28, 2020 @liambesaw it's very interesting, think it's going to be afew trial and errors my way until I get the perfect cone 6 If I followed the temperature schedule and the max temperature was 1220c and the cones overfired, do I only drop the max temperature and keep the rest of the segments the same? I'm a newbie so sorry for all these questions Link to comment Share on other sites More sharing options...
Bill Kielb Posted May 28, 2020 Report Share Posted May 28, 2020 2 hours ago, Danny said: @liambesaw it's very interesting, think it's going to be afew trial and errors my way until I get the perfect cone 6 If I followed the temperature schedule and the max temperature was 1220c and the cones overfired, do I only drop the max temperature and keep the rest of the segments the same? I'm a newbie so sorry for all these questions We still aren’t sure about your schedule with the overlaps in them so if you enter the schedule above and don’t have your cone right next to an element / sidewall and it still over fires meaning it flattens cone 6 reduce the final temp a few degrees at a time until you get a perfect cone six. Convention for using cone packs is Guide, Firing, Guard 5,6,7................. 5 for guide - 6 for firing or you target - and 7 as your guard. Folks who view the cones (with proper IR eye protection) watch their cones and as the guide bends they view more frequently until the firing cone bends and nearly touches, then they shut off their kiln. When their kilns are large and store lots of heat, they may find the cone 7 starts to fall in which case their next firing they may turn off their kiln when cone six is 3/4 down or earlier to account for the stored heat. It’s all a learning experience for the particular kiln. No holds at the top until you have a reason and you are not overfiring. Link to comment Share on other sites More sharing options...
Danny Posted May 28, 2020 Author Report Share Posted May 28, 2020 Ok thank you for your advice, fingers crossed for my next few firings! Link to comment Share on other sites More sharing options...
Sorcery Posted May 28, 2020 Report Share Posted May 28, 2020 Your margin of error is so small with that kiln, you might consider adjusting materials to the kiln, rather than adjusting the kiln (which is impossible imo) to the materials. The "burn out" sounds more like a glaze application that is too thin. Do you have room for cones 5 and 7? Sorce Link to comment Share on other sites More sharing options...
Danny Posted May 28, 2020 Author Report Share Posted May 28, 2020 Hello yes I have room for cones 5 and 7, at the moment I have only been putting in cones 4,5 and 6 because that was recommended to me before hand. My kiln only reaches max temperature of 1240c. It's just confusing because has I said in previous comments majority of the glazes have came out has expected and I'm happy with them, the odd few burnt out (possible because I didn't apply some thick) and the cones are overfired. Link to comment Share on other sites More sharing options...
Sorcery Posted May 28, 2020 Report Share Posted May 28, 2020 Your happiness is a better gauge than a cone! Sorce Link to comment Share on other sites More sharing options...
Danny Posted May 28, 2020 Author Report Share Posted May 28, 2020 @Sorceryoh right, I'm probably worrying about getting the cones perfect, but the clay is fully matured and the glaze looks good so I should be happy Link to comment Share on other sites More sharing options...
Sorcery Posted May 28, 2020 Report Share Posted May 28, 2020 Perfection of clay and glaze doesn't always, if ever, like up perfectly with a cone. The fact that you are getting good results in that little guy is a feat itself! I am impressed! Bravo! But.....pics or I don't believe it! Hehe! Sorce Link to comment Share on other sites More sharing options...
Danny Posted May 28, 2020 Author Report Share Posted May 28, 2020 @Sorcery I've tried to upload images but it's saying the photo is to big so it won't let me, any advice? Technology is not my thing aha Link to comment Share on other sites More sharing options...
Sorcery Posted May 28, 2020 Report Share Posted May 28, 2020 It stinks! But texting em to wife works for me! You want her number?lol! My problem now with technology, my phone has so little Storage, I don't have the room necessary to DELETE stuff! Wtf! Sorce Link to comment Share on other sites More sharing options...
Danny Posted May 28, 2020 Author Report Share Posted May 28, 2020 Finally uploaded, I need to work on my painting techniques! Link to comment Share on other sites More sharing options...
Danny Posted May 29, 2020 Author Report Share Posted May 29, 2020 The cone 6 did not overfire, thank you Link to comment Share on other sites More sharing options...
Bill Kielb Posted May 29, 2020 Report Share Posted May 29, 2020 4 hours ago, Danny said: The cone 6 did not overfire, thank you Hey, look at you. Success! Link to comment Share on other sites More sharing options...
Danny Posted May 29, 2020 Author Report Share Posted May 29, 2020 @@Bill KielbKielb thank you so much! Link to comment Share on other sites More sharing options...
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