H490 is H550 with 3.5% added yellow iron oxide. The red color only lasts until cone 8.


H490 fired test bars. Top is cone 10R. Below that going downward: cone 10, 9, 8 oxidation. Thus, the oxidation red color only holds under cone 8. For reduction, the both fires almost black. By cone 10R, it is behind to blister and melt.


H490 with Textured Engobe fired at cone 10R. By Joe Schmidt.

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702 Wood Street, Medicine Hat, Alberta T1A 1E9
Phone: 403-527-8535 FAX:403-527-7508
Email: tim.lerner@plainsmanclays.com