Direct on frit. general usage: it is a stable quality porcelain enamel frit, one coat one fire, can be applied to enamel cookware / gas stove / bbq. High quality direct on black enamel frit for enamel baking tray , find complete details about high quality direct on black enamel frit for enamel baking tray,cobalt nickel ground coat enamel frit,cobalt nickel ground coat,nickel ground coat frit from supplier or manufacturer-hunan noli enamel co., ltd. Our main products of enamel frits including ground coat, cover coat, transparent frit, matt enamel, direct on black frits and various cast-iron frits. high temperature inorganic pigment including red& yellow, blue, green, black oxide etc, widely used in porcelain enamel, ceramics, glass, coating,painting etc. Enamel cup is coated with vitreous porcelain enamel. the enamel frit is milled to enamel powder and after almost 1000 u2103 firing, it can adhere to its steel body. after cooling, the surface can be very smooth, itu2019s without any toxic material. except for all the advantages a glass cup have.