Mayco Stoneware SG-201 Black Cobblestone glaze, 118 ml

Mayco SG-201 Black Cobblestone – black glaze with a cobblestone texture

Mayco Stoneware SG-201 Black Cobblestone is an effect glaze that forms a textured, cobbled surface during firing. You apply it over another glaze. In the firing it breaks up into a black pattern of raised, irregular scales, and the glaze underneath shows through in the cracks.

The result depends on the firing temperature. At cone 06 (approx. 998 °C, guide value per Orton chart, oxidation) the shattered, raised scale pattern forms. At cone 6 (approx. 1,222 °C, guide value per Orton chart, oxidation) the glaze beads up on the surface. Over another glaze, the texture smooths out and shows a similar cobblestone pattern. For cone 10 (approx. 1,285 °C, guide value per Orton chart) in reduction, Mayco states the same behaviour as at cone 6. The glaze is developed for cone 06, so you can also fire it higher. In that case, make a test piece with your own clay in your own kiln first.

Applying the glaze

The pattern only forms in the firing, and you control it through the application. Stir the glaze well and apply it with a brush or sponge.

• 2 coats are recommended with a soft, wide brush; the second goes onto the still-wet first coat.
• A thick application gives large breaks, a thin one small breaks. If the application is too thin, the glaze does not break up.
• The pattern follows the direction of the brushstrokes.
• Touching up afterwards does not produce a break pattern.
• On unfired glaze the pattern is more pronounced than on glaze that has already been fired.

Choosing the base

Black Cobblestone does not break up on matt glazes, so use a glossy glaze as the base. The colour underneath shows in the cracks, so a light glaze gives the black scales a strong contrast. If you would like the pattern in white, there is SG-202 White Cobblestone.

Mayco SG-201 Black Cobblestone product details

• Manufacturer: Mayco, Stoneware SG-201
• Colour name: Black Cobblestone
• Pattern: black, shattered with raised, irregular scales
• Contents: 118 ml
• Firing: from cone 06 (approx. 998 °C, guide value per Orton chart), higher possible
• Atmosphere: oxidation (cone 06 and 6), reduction (cone 10)
• Application: brush or sponge, over any glaze

You will also need: soft, wide brush or sponge; a glaze as the base, for example a glaze in a contrasting colour

Do not spray. Use suitable personal protective equipment. Dried glaze tends to flake off, so handle it carefully.