The binder may be a fluoropolymer or an enamel frit. This mixture of silica and fluxes is called a frit. This is made from a hard white frit paste coated with transparent alkaline glaze. The key ingredient of vitreous enamel is finely ground glass called frit. Quartz sand may have been used to contribute silica to the frit. This porous frit is a salt bridge. Glass solders are available as frit powder with grain size below 60 micrometers. For wet application of enamel, a slurry of frit suspended in water must be created. The auxiliary electrode may be isolated from the working electrode using a glass frit. Two options are used, a glass frit bond ring or a metallic bond ring. When fired, the glass frit melts and binds the other components together. The earliest formulations were mixtures of clay and ground-up glass (frit). Regrinding and resintering the frit will create finer cuprorivaite crystals, also producing lighter shades. Scholars have suggested several potential connections between frit and faience. Then another layer of crystal was gathered over the frit.