Amanda Hummes Posted October 20, 2022 Report Share Posted October 20, 2022 Hello guys! I finally got my first kiln. It's a Skutt electric kiln. I have already did 2x bisque firings and unfortunately it was not a success. I programmed my bisque firing using CONE 04 - NO PRE-HEAT - NO HOLD, and for the second time I lost large pieces that I put in the same place inside the kiln. Any tips or suggestions for my third firing? What should I do to not lose some pieces again? Thank you, Amanda! =) Quote Link to comment Share on other sites More sharing options...
Kelly in AK Posted October 20, 2022 Report Share Posted October 20, 2022 Hi Amanda, congratulations on your new kiln, but sorry to hear you lost some work. If the pieces exploded you should definitely put in some preheat time. I fire a lot of student work, some of it not quite dry, and err on the side of caution. Eight hours preheat is my usual. If it’s all my work, it’s totally dry, and I know how thick every piece is, I still preheat for four hours. I’ve done less time successfully, I’m just so over blowing up pots that I don’t fool with it anymore. Rae Reich, Hulk, Amanda Hummes and 2 others 5 Quote Link to comment Share on other sites More sharing options...
Pres Posted October 20, 2022 Report Share Posted October 20, 2022 I moved this strand here so that it would be where most of the recent questions about new kilns and kiln firing is posted now. Sounds like you may have a calibration situation, and at the same time need help with the firing cycles @Amanda Hummes. @neilestrick who is very knowledgeable about kilns and firing will probably post in on this soon. Welcome to the forum, we hope you find many of your answers to questions here. Enjoy the journey! best, Pres Amanda Hummes and Hulk 2 Quote Link to comment Share on other sites More sharing options...
neilestrick Posted October 20, 2022 Report Share Posted October 20, 2022 @Amanda Hummes What exactly made the first two firings unsuccessful? Explosions? Cracks? Amanda Hummes 1 Quote Link to comment Share on other sites More sharing options...
Amanda Hummes Posted October 21, 2022 Author Report Share Posted October 21, 2022 On 10/19/2022 at 7:40 PM, Kelly in AK said: Hi Amanda, congratulations on your new kiln, but sorry to hear you lost some work. If the pieces exploded you should definitely put in some preheat time. I fire a lot of student work, some of it not quite dry, and err on the side of caution. Eight hours preheat is my usual. If it’s all my work, it’s totally dry, and I know how thick every piece is, I still preheat for four hours. I’ve done less time successfully, I’m just so over blowing up pots that I don’t fool with it anymore. Thank you so much for your answer Kelly! I will definitely try to use a pre-heat program. By the way, I don't have a vent, so I keep my first peephole open. With a pre-heat program, should I continue like this? Or do you suggest anything else? Also thought it might be a coolingdown issue but let's see the next chapter Lol. thank you again! Quote Link to comment Share on other sites More sharing options...
Amanda Hummes Posted October 21, 2022 Author Report Share Posted October 21, 2022 On 10/20/2022 at 4:10 AM, Pres said: I moved this strand here so that it would be where most of the recent questions about new kilns and kiln firing is posted now. Sounds like you may have a calibration situation, and at the same time need help with the firing cycles @Amanda Hummes. @neilestrick who is very knowledgeable about kilns and firing will probably post in on this soon. Welcome to the forum, we hope you find many of your answers to questions here. Enjoy the journey! best, Pres Thank you so much Pres! I'm so excited to be here sharing knowledge and thoughts about the ceramic process! thanks for the tip =) Quote Link to comment Share on other sites More sharing options...
Amanda Hummes Posted October 21, 2022 Author Report Share Posted October 21, 2022 17 hours ago, neilestrick said: @Amanda Hummes What exactly made the first two firings unsuccessful? Explosions? Cracks? Hello @neilestrick! Oh big explosions! The pieces literally exploded completely. My first thought was: - probably the temperature range up too fast? but on the second firing it happened again and I think maybe it's a cooling problem? Today I will do a glaze firing test with the pieces that have survived the last 2x bisque firings. Thank you, Amanda Quote Link to comment Share on other sites More sharing options...
Denice Posted October 21, 2022 Report Share Posted October 21, 2022 Big explosions, work wasn't entirely dry. I work with slabs and coils and will end up with some thick areas. If I only have one piece that I am concerned about I will stick in my kitchen oven and dry it for awhile at the ovens lowest temperature. Your a newbie and probably should use the preheat control, but you also need to learn when your piece is completely dry. Some potters put the pot against their cheek and if it feels cold then it is still wet. Denice Amanda Hummes and Pres 2 Quote Link to comment Share on other sites More sharing options...
neilestrick Posted October 21, 2022 Report Share Posted October 21, 2022 What Denice said. Explosions are caused by moisture. Even totally dry pots contain some moisture, which must evaporate out before it turns to steam and blows apart your work. When water turns to steam it expands 1700 times in size, so it's a powerful force. With thin pieces, the regular ramping rate of the kiln is slow enough to avoid explosions. But if you have large or thick pieces, it takes longer for that last bit of moisture to evaporate, so you need to do a preheat. Pres and Amanda Hummes 2 Quote Link to comment Share on other sites More sharing options...
Amanda Hummes Posted October 21, 2022 Author Report Share Posted October 21, 2022 4 hours ago, neilestrick said: What Denice said. Explosions are caused by moisture. Even totally dry pots contain some moisture, which must evaporate out before it turns to steam and blows apart your work. When water turns to steam it expands 1700 times in size, so it's a powerful force. With thin pieces, the regular ramping rate of the kiln is slow enough to avoid explosions. But if you have large or thick pieces, it takes longer for that last bit of moisture to evaporate, so you need to do a preheat. Thanks for the advice Neil. But I'm 100% sure that the pieces were completely dry. They were produced 1 month ago. Yes, I will definitely preheat for the next firings. But if this problem persists, do you suggest contacting a technician? thank you again. Amanda Quote Link to comment Share on other sites More sharing options...
Babs Posted October 22, 2022 Report Share Posted October 22, 2022 Had a sculptural piece of an old friend's, sat around for years , still exploded, damp inside. Explosion...water, cracking , another story or two. Quote Link to comment Share on other sites More sharing options...
neilestrick Posted October 22, 2022 Report Share Posted October 22, 2022 23 hours ago, Amanda Hummes said: Thanks for the advice Neil. But I'm 100% sure that the pieces were completely dry. They were produced 1 month ago. Even bone dry pieces contain water. Clay can't be 0% moisture sitting in a room that's 50-70% humidity. That last bit of moisture has to evaporate in the kiln before turning to steam, which takes longer for thick pieces, so a preheat or slower ramp is necessary. What speed did you use for the first firings? Never use Fast, especially for a bisque. Kelly in AK 1 Quote Link to comment Share on other sites More sharing options...
Pres Posted October 23, 2022 Report Share Posted October 23, 2022 Used to tell students that there were 3 types of water in the pots, Mechanical, atmospheric. and chemical. One is the water that makes the clay pliable, second is the water in the air and the pot cannot dry more than the air around it, and the third is the water chemically inherent in the clay and glaze materials. All of these have to be mitigated before and during a successful firing. best, Pres Quote Link to comment Share on other sites More sharing options...
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