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Ring-A-Day: Bad Sinter

Made this heavy BronzClay ring assuming that I had understood what went wrong previously. The ambient temperature was 47F when I turned the kiln on (it’s cold at Resistor on the weekends), so I added 20 degrees and an hour to the regular program — kinda like baking a bigger bird. Well, it looked good out of the charcoal until I hit it with the brass brusher, or maybe I should say the brass crusher. I quenched it when the temperature was around 500F, so that little bit of moisture combined with the bronze powder to make mud in a thin metal shell.

Back to the drawing board on the kiln controller.


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Ring-A-Day: Broken Shank BronzClay

Seems my PID is having trouble with the proper sintering temperature. I began the polishing by filing the imperfections out of the shank. Then when I attempted to round the ring on the mandrel, the shank split. I sawed off the broken parts to solder it back together, but the sawing exposed a hollow section with unsintered bronze powder inside. Then the ring split at the crown. End of ring.

My best guess is that the kiln is in a room where the ambient temperature is about 30 degrees lower than when the rings were sintering successfully, and the ambient temperature sensor is lowering the programmed temperature. I’ll add 30 degrees or use the AutoTune function again and see if that solves the problem.