Frit

A frit (sometimes spelled fritt) is a ground glass or glaze used in pottery. Some materials have to be fritted before they can be used because they are soluble or toxic. For example, some lead compounds are toxic, and borax, used in glaze as a flux and a glass former, is soluble. The modern potter uses lead as a frit of lead bisilicate (PbO.2SiO₂), lead sesquisilicate (2PbO.3SiO₂) or lead monosilicate (PbO.SiO₂). Borax will be used as a frit of sodium diborate (Na₂.2B₂O₃.10H₂O) or anhydrous borax (Na₂.2B₂O₃). [Fournier, Robert, "Illustrated Dictionary of Practical Pottery" (Van Nostrand Reinhold, 1973 ISBN 0-442-29950-8]

Near eastern pottery from the 13th century made use of frits in the clay body to achieve white wares that looked like Chinese porcelain, whose raw materials were inaccessible and little understood. Iznik pottery from the late 15th century was made of 80% silica, 10% glass frit and 10% white clay, with added lead and sodium compounds to reduce the firing temperature. [Atasoy, N., and Raby, J. "Iznik", (London, Alexandria Press, 1989)] In Europe from the 16th to the 18th century, several attempts were made to imitate porcelain using frit; these can be referred to as soft-paste porcelain although this terms also covers other formulations. The development of feldspar porcelain by the Meissen pottery lead most manufacturers to abandon frit bodies. However, some imitations of Iznik ware made at Kütahya today still use a frit body.

Frit is popular as a method of decorating handmade glass. It is utilized in both the offhand/furnace type of large scale glass work as well as the smaller scale flamework/lampwork process. Glass is crushed, graded according to size, and melted onto other glass to produce patterns and color. A common method of application is to roll the hot glass, hollow or solid, in frit. It can be sprinkled on to the pieces, or poured on the inside of a tube.

Lead Frit Paste is used in CRT manufacture to join the separate panel and funnel into a tube. [http://www.epa.gov/epaoswer/hazwaste/minimize/npep/success/sony.htm]

Frit also refers to the rapidly water quenched glass fragments of phosphosilicate glass (e.g. bioglass). Rapid quenching is used to avoid crystallisation and phase separation of light scattering dimensions.

References

See also

* Fritware