soda firing; soda glaze

Vapor-glazing process touted as modern-day nontoxic replacement for salt firing. Gives slightly less gloss and orange-peel. Instead of salt, soda ash (sodium carbonate) in water solution is sprayed into kiln at maturing temperature, and sodium vapor combines with silica in clay to form sodium-silicate glaze. Recent research indicates that effluent gases are highly corrosive and no more benign (or destructive) than salt-firing fumes. See salt firing.