Some thoughts off the top of my head. Seems to me you could pour
the investment into any container. The container is needed to
contain the investment until it solidifies. If the investment is
thick enough, once it solidifies, the container will be meaningless.
The investment will support itself.
When I first started vacuum casting I used steel cans from the
kitchen for flasks. When vacuum casting the lower ring of the can
must not melt so aluminum was out.
Your description leaves me to believe you plan on putting the metal
into the mold and place it in the oven. The oven will be heated as
rapidly as possible. Once the metal is melted you will turn off the
oven and let the metal solidify and cool down. The cool down time
could be lengthy.
You will find that if you are casting any metal that has copper in
you will get a coat of firescale the will be almost impossible to
remove. Firescale will be forming on the metal as long as it is
over about 1000 degrees.
Sounds like an interesting process, Don’t give up and don’t let
naysayers discourage you. Lee Epperson