Muffle Furnace

A muffle furnace is a heating device built so the material being heated is kept apart from the fuel and from the products of combustion, including flying ash and combustion gases, so nothing from the fire itself touches or contaminates the work. Potters use a muffle furnace to fire ceramics and apply enamel coatings, glassworkers use one to fuse glass, and it is also used for a controlled second firing of already glazed porcelain at a lower temperature than the first firing. A modern muffle furnace is usually an electric box shaped oven or kiln that heats the material by conduction, convection or radiation rather than by open flame, which gives the operator precise control over temperature and keeps the material clean of soot.