Home > Listing of Enamels > Vintage Enamel > Thompson OpaquesClick Image To View Larger 570 Violet (op) $4.00 Weight 1 oz ($4.00) 8 oz ($32.00) 16 oz ($64.00) 1609:=:4,1612:=:32,1613:=:64 Quantity: - + Opaque, un-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.