Let us say that one wants to burn out a flask and does not have a
kiln. What are the alternatives. Can you use a gas grill, a hot
plate, etc., etc. Please advise.
The method described in an old pamphlet on steam casting methods,
suggests taking a suitably sized red clay (terra cotta, I guess)
flower pot, lining it with a layer of furnace tape (this used to be
asbestos, but these days, is other mineral material. Works the same.
You may need to wet it to form it to the inside of the pot), and then
a layer of heavy aluminum foil. Keep the small hole at the bottom of
the pot open. Your flask goes, sprue down, on the kitchen stove
burner (either gas or electric), with the pot over it, set on high.
It will easily reach needed burnout temps this way. I recall being
able to get the flask to a nice low red/orange glow, easily near the
desired 1300F temps. One assumes the use of sufficient stove vent
fans, preferably the type vented to the outside, to handle wax
burnout fumes, and I'd suggest rigging up a steam dewax first, to
minimize fumes. When I did it, decades ago, I also took care that
the flask was off center on the burner, so over the liner under the
burner to catch drips, instead of over the hole often in the center
of such liners. You will want to get the permission of any
significant others who also use your kitchen before doing this.
Alternatively, any small electric hot plate that could equal a
typical stove burner should work as well, and that could be placed
outside or in the garage or something to avoid the ire of fellow
inhabitants. The real key to it all is the "kiln" made of the
insulated flower pot. Don't know about a gas grill, but if it directs
enough heat up into that pot, don't know why it wouldn't work...