Ryleigh Posted April 6, 2020 Report Share Posted April 6, 2020 I just fired my first glaze kiln 2 days ago and finally cracked it opened this afternoon at 150°. Each piece has at least 2-5 larger pinholes that are very noticeable. My clay body is a buff stoneware that fires between cone 2-7 and I’m using amaco PC glazes in an electric kiln. I just realized that my cone 6 setting on my kiln is closer to a cone 5 than it is a 6. My cone 7 setting is a cone 6. Should I refire to my cone 7 setting? The pinholes are really noticeable, and I don’t want to sell them looking like this.. Link to comment Share on other sites More sharing options...
liambesaw Posted April 6, 2020 Report Share Posted April 6, 2020 What kind of a bisque schedule did you use on the clay body? Link to comment Share on other sites More sharing options...
neilestrick Posted April 6, 2020 Report Share Posted April 6, 2020 If your clay body goes to 7 but you only fired it to 5, it may not be fully vitrified, and the clay could absorb and weep moisture. Link to comment Share on other sites More sharing options...
Ryleigh Posted April 7, 2020 Author Report Share Posted April 7, 2020 4 hours ago, liambesaw said: What kind of a bisque schedule did you use on the clay body? 250°/hr to cone 04 Link to comment Share on other sites More sharing options...
liambesaw Posted April 7, 2020 Report Share Posted April 7, 2020 3 minutes ago, Ryleigh said: 250°/hr to cone 04 Try slowing down between 1200 and 1700f a bit. Sometimes bisquing too fast will cause incomplete combustion of organics and sulfides. These can then later combust during a glaze fire. People who fire darker stonewares know it quite well and adjust accordingly. Some people just hold at 1700 for a bit on the way up, but the idea is to burn these out before the glaze firing to minimize gassiness. It may not be your entire issue, but it's where I'd start since you don't mix your own glaze. Link to comment Share on other sites More sharing options...
Ryleigh Posted April 7, 2020 Author Report Share Posted April 7, 2020 6 minutes ago, liambesaw said: Try slowing down between 1200 and 1700f a bit. Sometimes bisquing too fast will cause incomplete combustion of organics and sulfides. These can then later combust during a glaze fire. People who fire darker stonewares know it quite well and adjust accordingly. Some people just hold at 1700 for a bit on the way up, but the idea is to burn these out before the glaze firing to minimize gassiness. It may not be your entire issue, but it's where I'd start since you don't mix your own glaze. I’ll definitely try that with my next bisque firing! Now that I think about it that makes a lot of sense with the way some of the larger pinholes look. I would eventually like to mix my own glazes so I can dip. I am currently brushing on all of my glazes and it is very time consuming and expensive. Link to comment Share on other sites More sharing options...
Bill Kielb Posted April 7, 2020 Report Share Posted April 7, 2020 5 hours ago, Ryleigh said: 250°/hr to cone 04 This might be helpful Here is a popular slow bisque for automatic kilns that has been used very successfully for years and slows down in the right places to complete burnout that you can try. Many get by with the fast bisque as well. Depends on your clay. Link to comment Share on other sites More sharing options...
Ryleigh Posted April 8, 2020 Author Report Share Posted April 8, 2020 23 hours ago, Bill Kielb said: This might be helpful Here is a popular slow bisque for automatic kilns that has been used very successfully for years and slows down in the right places to complete burnout that you can try. Many get by with the fast bisque as well. Depends on your clay. Thank you, that is helpful! Link to comment Share on other sites More sharing options...
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