Rutile blue glaze effect completely lost! A temporary solution.

Friday 4th October 2013

Left: 4% rutile in the Alberta Slip:frit 80:20 base. This glaze has been reliable for years. But suddenly it began firing like the center mug! Three 5 gallon buckets of glaze (of differing ages) all changed at once. We tried every combination of thickness, firing schedule, clay body, ventilation, glazing method on dozens of separate pieces with no success to get the blue back. Even mixed a new batch, still no color. Finally the 'crow bar' method worked, 0.25% added cobalt oxide (right mug). It is identical ... amazing. It is not the same mechanism to get the color and it is not exactly the same, but worked while we figured out the real issue: the firing schedule (the secret turned out to be cooling, soaking, then slow cooling to 1400F).

Pages that reference this post in the Digitalfire Reference Database:

GA6-C - Alberta Slip Rutile Blue Cone 6, Rutile Glaze, Plainsman Cone 6 Slow Cool (Reactive glazes)

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