I garbage-picked an old 30" westinghouse electric range. It appears to have 31/2" or 4" of insulation on all sides of the oven. I'm impressed. I wonder what temp it could achieve. I'm only looking for 750F or maybe 800F-- pizza temp. The temp of the external sheet metal is likely to be a limiting factor, but that could be further insulated.The wiring could stink or fry, but a wiring upgrade wouldn't be too hard.