We are normally told that microwave ovens are strictly for food only, and that anything else will cause all sorts of bad things to come our way. There can be few readers who haven’t at some time seen the shower of sparks when an inadvertent metallic object finds its way onto the turntable.

A particularly useful non-food application for a microwave oven comes in the form of the small kilns sold for glass fusing. These are ceramic cylinders coated internally with silicon carbide, and [ShakeTheFuture] shows us how to make your own.

Key to the process is ceramic fibre insulation, which is bonded both to itself and to the fused silicon carbide grit by a cured solution of waterglass, sodium silicate. The result can easily reach the required temperature for fusing glass, but also has an application in burning out surplus wax or PLA from a plaster mould. It’s particularly interesting to see the technique with the waterglass in action, and you can see a run-down of the whole thing in the video below the break.