Refiring a terra cotta mug that had already bubbled only made it worse

Sunday 31st December 2017

Plus the glaze ran even more. The main problem was that the original firing was taken too high, about cone 02 (seven hour schedule). This body nears zero porosity there and is beginning to decompose. That generates gases. The second firing was taken to cone 03 in four hours. But the glaze just percolated more. However freshly glazed bisque ware in that same firing came out perfect. Lessons were learned. Fire faster. Keep it cone 03 or lower. Do not put the glaze on too thick. Use self-supporting cones to verify the electronic controller, they are much more accurate than regular cones.

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Terra cotta, Blisters

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