How is vitreous enamel fused onto a metal surface in enamelwork?

In enamelwork, vitreous enamel is fused onto a metal surface through a precise heating process. First, the enamel—a compound of flint or sand, red lead, and soda or potash—is melted into a clear glass known as flux, which is then pulverized into a fine powder.1

Before application, the metal surface must be thoroughly cleansed, typically by immersion in acid and water, followed by drying. The powdered enamel is applied to the metal, often using techniques such as champlevé or cloisonné to hold the material in place. Once the wet powder is spread, it is dried in front of a furnace.12

The object is then carefully introduced into the muffle of a furnace—a compartment shielded from direct flames—where it is heated until the enamel fuses and adheres to the metal base. This firing process typically takes only a few minutes, after which the object is withdrawn and allowed to cool, resulting in a durable, glossy, and decorative finish.13