Enameling is a different process, where powdered glass is fused by heat to a metal or glass surface.
When heated, the ground, powdered, colored glass liquified and flows down onto the surface. One technical term it that it fluxes to the surface, and a close, intimate bond is developed, similar to a good glue.
I realize this is simplified, but, follow me here, please.
When dissimilar materials with different coefficients of expansion and sensitivity to heat and humidity are glued together, the weak link between everything is the glue. Over time and exposure to conditions relevant to the inherent weaknesses of each material losses can occur when the glue fails.
If two materials have a true molecular bond, these issues, (sensitivity to temperature, humidity, coefficients of expansion) do not come into play as the different materials are close enough to each other in these sensitivities so as not to be affected.
Examples of true molecular bonds include welds of layers of steel in blades (not crucible Damascus), and diffusion bonding of dissimilar metals as used by the Japanese in Mokume-Gane, or wood grain metal. In either case, no extra filler material or solder is added. Molecules of each layer are exchanged by high heat and an intimate contact, sometime assisted by the hammer or pressing under pressure while at temperature.
|