mrcasey Posted September 10, 2014 Report Share Posted September 10, 2014 I recently got some disappointing results from a glaze firing. There are these little pimply - welty looking things all over a few of my pots. There aren't any holes in the glaze. I fired to cone 6 in an electric kiln. My clay body is Laguna 609 #65. A friend of mine dug some native clay, added ball clay, and put it in our pug mill. I got a little bit of that mixed in with the 609. Don't know if that's an issue or I got lazy with my wedging. I've never had this problem before. Casey Link to comment Share on other sites More sharing options...
Pres Posted September 10, 2014 Report Share Posted September 10, 2014 I think your clay may have gotten contaminated by something in the other clay. I can't be certain, but I have only seen this one other time when a clay with a different feldspar and composition was put in our pug mill by a student. She had brought the clay in from home, and thought it was OK to use as she had purchased it the year before. No box, bag only, no label. I only found out about it later. We had a few loads of pottery with this problem. Link to comment Share on other sites More sharing options...
neilestrick Posted September 10, 2014 Report Share Posted September 10, 2014 Looks like bloating to me. Most likely an issue with the local clay if it's never happened before. Link to comment Share on other sites More sharing options...
Min Posted September 10, 2014 Report Share Posted September 10, 2014 Sounds like it's time for your friend to come and clean out your pugger. Link to comment Share on other sites More sharing options...
alabama Posted September 11, 2014 Report Share Posted September 11, 2014 hey, If the pieces are non-functional, it might be ok since it only affects the asthetic surface. Of course, if you're a famous potter, the critics are going to say,"OMG, the pimply surface is the best texture I've ever seen"!! ;>) "How was it done, can you tell us the secret"? It was probably caused by some contamination in the natural clay composition... like calcium, lead, or any other material not rated for your heat range, since this was the first encounter.. Just for fun, break open one of the bumps and see if some type of white calcium hydroxide powder falls out... If it doesn't see if it is some type of garnet stone. Your options may be to throw it all away, or make garden toads and toad furniture with it. : ) Don't beat yourself or friend up too much... Its almost like a rite of passage, which didn't turn out your way. I've seen disasters that turned out pretty good. Good luck, Alabama Link to comment Share on other sites More sharing options...
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