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I finally have a perfect functional, durable gunmetal black! It has an incredible silky surface. It does not cutlery mark. It does not craze on anything. It is easy to clean. This is G2934Y with 6% Mason 6600 black stain fired using the PLC6DS schedule. I had to tune it a bit, adding about 15% glossy G2926B, because it was a little too matte on initial firings. But now it is perfect. These are heavy mugs made using the M340 casting recipe (and the casting-jiggering process). The speckled mug was made by casting a thin layer of the speckled version of the slip first, then filling the mold with the regular slip. I used a 40-minute cast to get walls nice and thick!
This is the G2934Y satin matte glaze recipe with Mason 6600 black stain (6%). The piece on the left was fired using the C6DHSC firing schedule (drop-and-hold at 2100F then 150F/hr to 1400F). The one on the right was fired using the PLC6DS schedule (drop-and-hold at 2100F then free-fall from there). The slow cooling rate gives the glaze on the left time to crystallize, creating a stony matte (and altering the colour accordingly). My kilns are generally lightly loaded, so free-fall firings drop rapidly, producing the effect on the right. This phenomenon is a characteristic of high MgO glazes (ones having significant dolomite, talc, Ferro frit 3249). To vary, by recipe, the degree of matteness, we also make this glaze using a blend of G2934 base (which fires even more matte on slow-cool) and G2926B glossy (starting with and 80:20 matte:glossy mix). Of course, this type of glaze would not be practical in an industrial shuttle kiln, pieces would fire differently depending upon their placement on the cars.
Glossary |
Gunmetal glaze
A type of ceramic glaze: Pebbly matte black. For functional surfaces, it has enough glossy to not cutlery mark and be easy to clean. |
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Materials |
Mason 6600 Black Stain
A cobalt-containing stain useful in bodies, engobes and glazes at a wide range of temperatures. |
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