Does the microwave kiln ruin a microwave oven due to heat buildup?

Protect the microwave oven from heat damage by placing 3 – 1/2” ceramic posts under the kiln. If you remove the MagicFuse microwave kiln after the glass has fused, the heat will not build up inside the microwave oven. Allow the MagicFuse to cool outside the oven on a heatproof surface such as a large ceramic shelf. The MagicFuse reaches around 1650 F when the glass begins to fuse. This is a higher temperature than you will ever encounter in your kitchen. But the firing is so rapid that the heat does not have time to work its way to the outside surface of the kiln.