Spectrum 878 Cosmic Copper Raku Glaze

Spectrum 878 Cosmic Copper Raku Glaze develops an intense copper metallic effect with natural tonal transitions created during post-firing reduction.

Spectrum Raku Cosmic Copper is formulated to produce an intense copper effect. After reduction, it can develop red-copper, brown and more mirror-like areas whose distribution depends on the firing conditions.

Spectrum Raku Glazes

Spectrum Raku is a series of ready-to-use brush-on glazes formulated for raku firing. The manufacturer recommends applying 2-3 coats to bisque ware, allowing them to dry completely, and firing to 950°C. The hot ware is then transferred to a reduction container filled with combustible material such as sawdust, straw or dry leaves.

Raku firing results are inherently variable and depend on the clay body, glaze thickness, firing temperature, reduction material and the reduction process itself. To obtain effects similar to those shown on the samples, keep the ware in a reduction atmosphere for at least 20 minutes. A thinner glaze application can intensify metallic effects in many colors. Once fully cooled, the surface can be cleaned with water and a scouring pad to reveal the sheen and color more clearly.

Spectrum 878 Cosmic Copper Raku Glaze

• After reduction, the glaze develops intense red-copper and metallic areas.
• The manufacturer recommends applying 2-3 coats of glaze to bisque ware and allowing them to dry completely before firing.
• The glaze is intended for raku firing at 950°C.
• After firing, the ware requires post-firing reduction. For results similar to the samples, we recommend at least 20 minutes in a reduction atmosphere.
• The final result can vary depending on the clay body, glaze thickness and reduction process, so testing on a sample tile is recommended.
• The glaze is not intended for food-contact surfaces.