If you make a shallow hole in the bottom of the lower firebrick - as well as the hole for the cricible in thev top of it, the revolving pin in the centre of the microwave can revolve freely within the hole. The glass plate and the plastic revolver wheels can be taken out, which gives a little more space for the bricks and removes any risk of damage to the glass. There is no need to revolve the firebricks within the microwave oven..
If you don´t let the quadratic brick turn, you can, theoretically, use a much bigger brick (such a big one, that its corners wouldn´t allow for turning anyway), and so reach higher crusible-temperatures. Although you shouldn´t use up the whole energy just to heat up an ever bigger brick, but the crusible, of course. Nevertheless, a balance would be easy to find, and after all, you just trade time for higher temperatures, which is a good deal...
i heard something about crushing up Pyrex glass that's designed to handle high temp much like graphite(pencil lead does) helps to bring the gold up to temperature, warning is don't let the gold get to 4000 deg c or it vaporizes, i wonder if Sodom/Gomorrah brimstone would be good additive to fire-clay crucibles, hint use conical shaped (reverse cone like upside-down)
The inside of the walls of the top part of the kiln is coated with Silicon Carbide or Graphite dust, these two materials absorb a lot of the microwave radiation which they convert to heat.
Тигель скорее всего из карбида кремния имплантированной окислом железа, так же касается подсыпании этого же материала, только в тигель добавлен каолин, термоизоляция ШПГТ.
