Thompson Enamel is the finest quality enamel available on the market and is carefully formulated in the United States and designed to perform consistently. 1997 Crackle Base Black Thompson Opaque Enamel - 80 Mesh Medium Temperature Medium Expansion Enamel for Copper, Gold, Silver, Low Carbon Steel & Metal Clay. Normal firing temperature range is 1400-1500 degrees fahrenheit. Coefficient of Expansion Range is 258-360 cubic expansion. Made lead-free in the USA. Available in 1 Ounce Jar, 2 Ounce Jar, 8 Ounce Jar, & 5LB Container.