The general firing range for Thompson enamels is 1400°–1500°F (760°–815°C). Enamels will fuse in 1 to 4 minutes depending on the color, type and thickness of the metal, and the temperature of the kiln. A typical firing is 1450°F (790°C) for around 2 minutes. Enamel powders will change in color after firing. Refer to the color image for a general indication of the fired result. Computer monitors do not accurately represent color, and enamel colors may vary slightly from batch to batch, so pre-testing your enamels before using them is recommended. Bronze is not recommended for enameling. The enamels are not formulated to adhere to it and will crack or chip off.

Color Specific Information:

• Color: 2720 Harold Purple
• Metals: Recommended for fine copper and gold. Not recommended for silver. See additional firing notes below. Recommended Firing Range:
• Consistent with general firing range.
• Firing: Additional firing time and/or multiple firings may be required.
• COE: 315 cubic expansion
• Grade: 80 Mesh
• Type: Transparent
• Color Code: (G) contains Gold

Additional Firing Notes:
Transparent G colors may require more than one coat and multiple firings to develop the color. This color reacts with both copper and silver. Firing on Copper: Firing over a flux layer will completely eliminate the problem as can be seen on the copper sample pictured. If firing over clear, the initial firing should be 1550°F (845°C) to clear the oxides off the metal. The copper should appear clean and bright under the enamel. If it appears reddish or mottled it wasn't fired hot enough and/or long enough. Refire at high temperature. Subsequent color firings should be at lower temperatures. Firing on Silver: The silver sample pictured is sheet metal and was fired directly and over a single layer of 2040 Clear. The reaction is somewhat mitigated over the clear, but there is still bleed through. If attempting on silver, fire at least two layers of 2020 or 2040 Clear first, and then reduce the temperature of the kiln before firing the color. This technique often works well on sheet metal, but is less effective on metal clay due to its porosity which releases more silver salts into the enamel. Color reaction frequently bleeds through even with the clear barrier underneath. Be sure to test techniques before committing a valuable piece. Overall, this is not a color recommended for silver for those less experienced with enameling. It's important to become comfortable and achieve some level of success with the Standard and (A) colors before trying the more challenging colors.

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©2013 - The color notes presented here are the intellectual property of Pam East and reproduction in whole or part in any form requires written permission.