Home > Listing of Enamels > Vintage EnamelClick Image To View Larger 967 Sapphire (op) $7.00 Quantity: - + Opaque, cataloged, Thompson Enamel for Copper, Silver, Gold, Iron and Steel. This enamel is "medium fusing" and should be fired at 1450 to 1550 degrees F. for approximately 2 to 4 minutes. All Enamel is pre-1990, 80 mesh and lead bearing.