What Type of Acid Is Used to Etch Glass?
Historically, glass has been etched with the corrosive and dangerous hydrofluoric acid, a combination of hydrogen and fluorine. Because of its reactivity, hydrofluoric acid must be stored in polyethylene or polytetrafluoroethylene containers. The acidic salt ammonium bifluoride has sometimes been formulated with other substances to form a “safer” etchant for glass. Unfortunately, this may lead to a false sense of security. Ammonium bifluoride is compounded with inert ingredients, and though not quite so strong as straight hydrofluoric acid, is capable of inflicting similar damage.
