Wound temperature, thermal insulation

Furnaces. Electric furnaces are used for higher temperatures. These are obtainable commercially, but satisfactory ones can be made in the laboratory (see Fig. 24-1). A pregrooved Alundum core is wound with suitable heating wire (nichrome, Chromel A, Kanthal) of 12 to 20 gauge, and covered with a thick coating of Alundum cement. This is surrounded by several inches of powdered magnesia, for thermal insulation, in a large... 

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