oholiabs Posted January 27, 2019 Report Share Posted January 27, 2019 I fired several pieces made from Laguna Bmix clay WC401. They came out of the bisque firing of cone05 just fine, but when glazed and fired to cone 6 the pieces melted completely? Any idea why? The glazes were commercial cone 6 glazes. I've read you can fire to cone 6 with no problem. Link to comment Share on other sites More sharing options...
neilestrick Posted January 27, 2019 Report Share Posted January 27, 2019 12 minutes ago, oholiabs said: I fired several pieces made from Laguna Bmix clay WC401. They came out of the bisque firing of cone05 just fine, but when glazed and fired to cone 6 the pieces melted completely? Any idea why? The glazes were commercial cone 6 glazes. I've read you can fire to cone 6 with no problem. Do you mean the clay itself melted, or just the glazes melted too much and ran? The only way a clay body would melt at cone 6 is if it was actually a low fire white body. Any chance you grabbed the wrong clay? Any chance the kiln over fired? Link to comment Share on other sites More sharing options...
hitchmss Posted January 27, 2019 Report Share Posted January 27, 2019 Agree with Neil; what actually melted? Photos would be helpful. I use Bmix, but for cone 10; I fire it to cone 12, and it handles the extra temp with no issues. Ive had it all the way up to 14 with very minimal bloating. I cant imagine that if what you actually used, was Bmix 5, that the recipes are so far different, that even if you did overfire by 2-4 cones, that you'd have a puddle where there used to be a pot. The only time I ever saw a pot (clay, glaze, and all) completely melt, was some paper porcelain, which was loosely folded (origami style) into a vase shape, and fired to a cone 10 in a salt kiln. The 10" pot was literally a 1/2" puddle when we opened. Otherwise, Ive never seen a pot truly melt. Link to comment Share on other sites More sharing options...
Denice Posted January 27, 2019 Report Share Posted January 27, 2019 The only clay I have seen completely melt was a low fire clay when I was in high school. The teacher left it firing overnight thinking the sitter would turn it off, it didn't. It was a load of his work not the students. Denice Link to comment Share on other sites More sharing options...
liambesaw Posted January 28, 2019 Report Share Posted January 28, 2019 I've fired bmix 5 to cone 9 and it bloated and deformed but didn't melt into a puddle, just sagged a little. Link to comment Share on other sites More sharing options...
oholiabs Posted January 28, 2019 Author Report Share Posted January 28, 2019 Thanks for the replies. The entire piece melted, after surviving a cone 04 bisque.. no other piece in the kiln melted. I don't think it was a mix up with clays because I only have the one white clay body in the studio. Link to comment Share on other sites More sharing options...
neilestrick Posted January 29, 2019 Report Share Posted January 29, 2019 3 hours ago, oholiabs said: Thanks for the replies. The entire piece melted, after surviving a cone 04 bisque.. no other piece in the kiln melted. I don't think it was a mix up with clays because I only have the one white clay body in the studio. Low fire white bodies will melt by cone 3. If you still have some of that clay left, make a little tiny pinch pot with it, put it inside of a pinch pot that you know will survive, and fire it in the next cone 6 load and see if it melts. If it does, then you've probably got a box of clay that was labeled wrong or mixed wrong. Link to comment Share on other sites More sharing options...
glazenerd Posted January 29, 2019 Report Share Posted January 29, 2019 You would have nearly double the amount of feldspar in a cone 6 to create a puddle. Krueger pottery purposely fried an old kiln for a display at NCECA 2016 in KC. After Ryan and I hot wired it to over fire: I sprinkled a cup of cryolite over the broken cups and plates. It takes some doing to get clay to melt into a puddle. T Link to comment Share on other sites More sharing options...
neilestrick Posted January 29, 2019 Report Share Posted January 29, 2019 56 minutes ago, glazenerd said: You would have nearly double the amount of feldspar in a cone 6 to create a puddle. Krueger pottery purposely fried an old kiln for a display at NCECA 2016 in KC. After Ryan and I hot wired it to over fire: I sprinkled a cup of cryolite over the broken cups and plates. It takes some doing to get clay to melt into a puddle. T That sounds like fun! I was thinking maybe they used frit or talc instead of feldspar by accident. Expensive accident if they used frit. Link to comment Share on other sites More sharing options...
Mark C. Posted January 29, 2019 Report Share Posted January 29, 2019 My only question have you worked with low fire clay at all in the last few years?? If that answer is yes I'm betting 100% its a mix up. I have seen low fire flow into a puddle at cone 11. I have also seen cone 5 B mix at cone 11 boatup like the Michelin man. It did not run but was more like expanded dough. Link to comment Share on other sites More sharing options...
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