MarkS Posted January 30, 2011 Report Share Posted January 30, 2011 I'm relatively new to ceramics and recently fired my first kiln load of glazed items. Most, if not all seem to have this "pitting" regardless of the type of glaze. I fired to ^6 in the kiln sitter and then an additional 30-45 based on the cone on the shelf not having bent yet. I had the Firemate speed control set to medium and started at "0" on the power control. What caused the problem I'm seeing and what do I do about it? Thanks! P.S. This is also my first attempt at Ancient Jasper Link to comment Share on other sites More sharing options...
Denice Posted January 30, 2011 Report Share Posted January 30, 2011 I'm relatively new to ceramics and recently fired my first kiln load of glazed items. Most, if not all seem to have this "pitting" regardless of the type of glaze. I fired to ^6 in the kiln sitter and then an additional 30-45 based on the cone on the shelf not having bent yet. I had the Firemate speed control set to medium and started at "0" on the power control. What caused the problem I'm seeing and what do I do about it? Thanks! P.S. This is also my first attempt at Ancient Jasper Mark, you need to give us a little more information because pitting can be caused by several things. What cone was your clay and what cone was your glaze to fire at. Did you bisque and what cone did you fire that to and was it a fast or slow firing. Did you clean your pieces before you glazed them. This information will help someone who is familiar with the Firemate system answer your question. Denice (Wichita, KS) Link to comment Share on other sites More sharing options...
MarkS Posted January 30, 2011 Author Report Share Posted January 30, 2011 The items were bisque fired to ^04. I blew or hand wiped the dust off the items before applying glaze and I wondered if this was the problem. The clay was several varieties of mid-fire stoneware clay with Amaco high-fire glazes - all new. It was then fired to a good ^6 - the cone was completely bent over. As best I understand it the speed control regulates how much power is passed to the coils versus time. At medium setting it might be increasing 10% an hour. Based on the appearance of this glaze I'm thinking it got too hot. Link to comment Share on other sites More sharing options...
Pres Posted January 31, 2011 Report Share Posted January 31, 2011 The items were bisque fired to ^04. I blew or hand wiped the dust off the items before applying glaze and I wondered if this was the problem. The clay was several varieties of mid-fire stoneware clay with Amaco high-fire glazes - all new. It was then fired to a good ^6 - the cone was completely bent over. As best I understand it the speed control regulates how much power is passed to the coils versus time. At medium setting it might be increasing 10% an hour. Based on the appearance of this glaze I'm thinking it got too hot. Sounds like to me the ware was still dirty. Try a damp sponge wash after brushing of the dust/dirt with a soft brush. Two things will happen with the damp sponge wash-remove finer dirt/dust, and put a small amount of moisture into the pot that will help with a smoother layer of glaze. Link to comment Share on other sites More sharing options...
MarkS Posted February 1, 2011 Author Report Share Posted February 1, 2011 Well, I was thinking dust could be the problem but had also read somewhere that it could be caused by getting too hot or cooling too fast. Any thoughts about that? If the Kiln Sitter shuts off the kiln is it OK to let it cool naturally to ambient temp? Thanks! Link to comment Share on other sites More sharing options...
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