Amy B Posted September 29, 2020 Report Share Posted September 29, 2020 What causes glaze to fade/ change color after running in dishwasher? This is a new piece so its not a wear and tear issue. I bisque fired to cone 04 and fired to cone 5. Use commercial food safe glazes, all one color, no layering but after a dishwasher run, it had spots of blue come out under the green..... it actually looks neat but I’m worried about the safety of it. Link to comment Share on other sites More sharing options...
Callie Beller Diesel Posted September 29, 2020 Report Share Posted September 29, 2020 Anything that fades after one dishwasher run has something very wrong with it, and no, I would not consider those pieces safe for use. What clay and glaze are you using? Can you post an image from your phone? Link to comment Share on other sites More sharing options...
C.Banks Posted September 29, 2020 Report Share Posted September 29, 2020 The issues of glaze durability and 'food safety' are a bit of a kettle of fish. A glaze breaking down after one dishwasher run something I'd be worried about too. I certainly wouldn't promote the surface as durable. If your glaze firing went as recommended by the supplier I'd be disappointed as I imagine you are as well. The long answer is quite long. Digitalfire and Glazy are good places to start. They will be intimidating if you are unfamiliar with some of the language. Ultimately dishwashers are notoriously hard on ceramics. The temperature changes, detergent and alkalinity levels will test the best of glazes. hope this helps a bit without complicating the matter too much Link to comment Share on other sites More sharing options...
Min Posted September 29, 2020 Report Share Posted September 29, 2020 3 hours ago, Amy B said: What causes glaze to fade/ change color after running in dishwasher? This is a new piece so its not a wear and tear issue. An unbalanced glaze that is under supplied in alumina and silica or an overload of heavy transition (heavy) metals or underfiring (resulting in an undeveloped glassy matrix). Link to comment Share on other sites More sharing options...
liambesaw Posted September 29, 2020 Report Share Posted September 29, 2020 Especially common in glazes containing copper as the colorant. Dishwashers are a great test of glaze durability, the heat, the strong alkali and strong acid involved will make quick work of a non durable glaze. In commercial glazes the only measurement of food safety is the leachable lead and cadmium levels. There is no requirement for them to manufacture or develop a durable glaze. Link to comment Share on other sites More sharing options...
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