Frit

Frit is a granular or powdered glassy material produced by partially melting a batch of silica and fluxes, then rapidly cooling the melt to solidify it before full fusion. The resulting frit is typically milled to specific particle sizes and sold as a ready-made ingredient for glaze and ceramic body formulations.

In ceramics and glassmaking, frits serve mainly as fluxes that lower the melting point of glazes and promote a uniform, glassy surface. They can include silica, flux components such as soda, potash, or boron, and colorants or stabilizers. By providing predictable melting behavior, frits help produce durable glazes with reduced shrinkage and fewer defects. Frits are also used in fritware, a type of ceramic body developed in the Middle East in which ground glass frit is added to clay to form a workable, translucent material and to aid glaze compatibility.

In laboratory and industrial settings, the term frit also refers to a porous ceramic filter, such as a fritted glass or porcelain disc, used in vacuum filtration. These frits support a membrane or paper and allow liquids to pass through while retaining suspended solids.

Historically, frit materials have been important in the production of tin-glazed and faience wares, where frit-based glazes or frit-rich bodies contributed to gloss and translucency. Today, frits are widely produced and standardized for use across ceramics, glass, and filtering applications.