You seem to have a fundamental misunderstanding about how crucibles operate. The outside of the crucible is not supposed to get particularly hot. Heat is applie

You seem to have a fundamental misunderstanding about how crucibles operate. The outside of the crucible is not supposed to get particularly hot. Heat is applied to the inside; the crucible contains both the material and the heat. If you don’t do this then all the air in the room is also heated up to ludicrous temperatures, and that tends to be bad for any other equipment or people nearby.