tokati Posted February 18, 2023 Report Share Posted February 18, 2023 Recently in our glaze firings to 1250 deg C in an electric kiln, the bottoms of our pots have been making this darker toasty patch, sometimes completely covering the bottom and other times with this kind of pattern. One of my studio mates seems to think its from the glaze of other pots, but I doubt it, since there would be a darkening on the walls of pots. Especially considering that the attached photo was unglazed on the outside and there was no effect on that part. Has anyone experienced and diagnosed this issue? Any information would be appreciated. Quote Link to comment Share on other sites More sharing options...
Callie Beller Diesel Posted February 18, 2023 Report Share Posted February 18, 2023 Hi and welcome! if it’s only appearing on the bottom of the pots it’s possible that there’ something on the kiln shelves or kiln furniture that’s fuming. If the shelves are old and have glaze drips that have been kiln washed over, there’s still things that can come through. If that’s the case, grinding shelves to remove all old bits and pieces, and apply fresh kiln wash ought to fix it. Hulk and Rae Reich 2 Quote Link to comment Share on other sites More sharing options...
Babs Posted February 19, 2023 Report Share Posted February 19, 2023 Any manganese drips in your kiln? Any contamination when sponging or drying pots. Change when you glaze and fire again? Quote Link to comment Share on other sites More sharing options...
High Bridge Pottery Posted February 19, 2023 Report Share Posted February 19, 2023 Could be soluble salts in the clay - https://digitalfire.com/glossary/soluble+salts Hulk, Callie Beller Diesel and Rae Reich 3 Quote Link to comment Share on other sites More sharing options...
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