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mat glazes12/1 si/al ratio

updated thu 1 jan 04


Craig Martell on wed 31 dec 03

>.If a glaze has a Si:Al ratio of 12:1 no amount of slow cooling is going
>to make it matte..


I guess, as usual, this depends on the total glaze makeup. One of the
first blue celadon glazes I made that actually produced the sky blue color
had a Si/Al ratio of 12 to 1 and it was semi matt from mostly undisolved
silica. There wasn't enough Ca in the glaze to make a calcium matte. To
back this up a little more, I made another glaze with the same molecular
equivalents in the fluxes, but the Si/Al ratio was about 9.5 to 1. This
glaze is very bright and shiny. All the silica has been disolved producing
a glassier matrix. That's my take on things anyway.

regards, Craig Martell Hopewell, Oregon