Porcelain enamel frit is a form of glass bonded to metal on a molecular level at high temperature. this results in a typical and unique composite material of glass and metal, which combines the positive qualities of both materials. specifications of porcelain enamel frit for ground coat: Vitreous enamel coating combined with cover coat in high level porcelain signs enamel mid temperature co-ni frit vitreous enamel coating combined with cover coat in high level porcelain signs enamel mid temperature co-ni frit About pei. the porcelain enamel institute, inc. (pei) is an organization of volunteers who actively support the porcelain enamel industry in north america; this includes the actual enamelers as well as many companies who provide raw materials, equipment and technology. 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.