PaulR Posted September 16, 2018 Report Share Posted September 16, 2018 I just finished a bisque firing where I had used stains and underglazes on greenware. They came out exactly like I wanted so I do not need to do anything else to the pots. Is it ok to immediately start the glaze firing? Is it better for the pots or the kiln to be completely cool? The kiln reads 100 degrees, will that hurt if I start the glaze firing? Thanks for any advice. Link to comment Share on other sites More sharing options...
Chilly Posted September 16, 2018 Report Share Posted September 16, 2018 When you say you don't need to do anything, does that mean you are not glazing them? Link to comment Share on other sites More sharing options...
PaulR Posted September 16, 2018 Author Report Share Posted September 16, 2018 No glaze, just the stains and underglazes that were put on before bisque firing. Link to comment Share on other sites More sharing options...
Min Posted September 16, 2018 Report Share Posted September 16, 2018 It's fine to start the kiln while still warm. Going forward, if you are not glazing you can single fire (bisque and glaze in one firing) and go to whatever cone you are "glaze" firing to. This type of single firing goes slow like a bisque up to your bisque cone/temperature then proceeds with the remaining firing going at the schedule for the glaze firing from the peak temperature of your bisque to your final "glaze" cone/temperature. Do you have a programmable controller or a manual kiln and what cone are you firing to? Link to comment Share on other sites More sharing options...
PaulR Posted September 16, 2018 Author Report Share Posted September 16, 2018 It's an Easy fire automatic L&L kiln and I fire to cone 6. I tried letting some pots dry longer and then fired them at cone 6 with no bisque firing and they all blew up. They seemed completely dry so not sure why. Link to comment Share on other sites More sharing options...
Min Posted September 16, 2018 Report Share Posted September 16, 2018 2 hours ago, PaulR said: It's an Easy fire automatic L&L kiln and I fire to cone 6. I tried letting some pots dry longer and then fired them at cone 6 with no bisque firing and they all blew up. They seemed completely dry so not sure why. Moisture in the pots will cause them to blow up. Put a room temperature pot against your cheek and if it feels cool on the bottom then it's still not dry. If you used a cone 6 glaze firing program it likely went too fast through the lower temperatures. There are charts here showing what the ramps are using the controllers that are on the L&L kilns. If you do a mash up of a ^04 bisque with an average ^6 glaze program you would have something like this: (all in F) 80 / 250 / hold for 2-3 hours if you are not sure the pots are dry or if they are thicker than 3/8" or so 200 / 1000 / 0 hold 100 / 1100 / 0 hold 180 / 1676 / 0 hold (from here on it goes to the latter part of a med/fast ^6 glaze firing schedule) 400 / 2000 / 0 hold 108 / 2130 or until cone 6 is down kiln off Link to comment Share on other sites More sharing options...
AndreaB Posted September 17, 2018 Report Share Posted September 17, 2018 Is there any advantage to leaving a vessel unglazed? I did try this and found that the surface scratched very easily. How could I avoid this happening? I did glaze the inside, my thinking being that if the vessel were to be used for food purposes then it would be food safe. I do like the look of a matt unglazed surface. A pic of a local potter's bowl is attached. Thanks Link to comment Share on other sites More sharing options...
Rebekah Krieger Posted September 23, 2018 Report Share Posted September 23, 2018 On 9/17/2018 at 4:45 PM, AndreaB said: Is there any advantage to leaving a vessel unglazed? I did try this and found that the surface scratched very easily. How could I avoid this happening? I did glaze the inside, my thinking being that if the vessel were to be used for food purposes then it would be food safe. I do like the look of a matt unglazed surface. A pic of a local potter's bowl is attached. Thanks It sounds like your pots might not have been vitrified. What cone is your clay vs the firing that you did? Link to comment Share on other sites More sharing options...
oldlady Posted September 24, 2018 Report Share Posted September 24, 2018 PAUL R, is there an electronic controller on your L&L? there is a preheat section on mine and i use it all the time because i single fire. i am not suggesting that you single fire but if you do have a controller, try the preheat with a hold time of an hour to thoroughly dry your work before the temperature rises. then try slow glaze to the cone you wish. just to see if that will work. Link to comment Share on other sites More sharing options...
Chilly Posted September 24, 2018 Report Share Posted September 24, 2018 On 9/16/2018 at 8:10 PM, PaulR said: They seemed completely dry so not sure why. How thick were they? Did they have enclosed hollow areas? Link to comment Share on other sites More sharing options...
AndreaB Posted October 27, 2018 Report Share Posted October 27, 2018 On 9/23/2018 at 8:50 PM, Rebekah Krieger said: It sounds like your pots might not have been vitrified. What cone is your clay vs the firing that you did? I bisque fire to 1000 deg C and glaze fire to 1222 Link to comment Share on other sites More sharing options...
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