Factors Affecting Bubble Formation In Vitreous Enamels

The fact that vitreous enamel coats have a bubble-structure has been realised for some considerable time, but the matter was brought back into prominence recently by a paper which Charlish and Heeley gave to the IVE, which showed that, in certain cases, this structure could cause serious defects, in that some of the bubbles extended right from the surface of the enamel coat to the metal base. This article attempts to decide, if possible, how this structure originates, and also, attempts to throw some light onto the question of the contents of the bubbles.