Casting machine material

I am trying to build a vacuum investment casting machine for lost wax casting of high temperature materials (inconels and other nickel
superalloys).
The heater will be induction, either a ready-bought one or one I build myself. It will melt the casting material in vacuum, then cast it under argon pressure and/or gravity into an evacuated mould.
My problem is what to make the case out of.
A rough design might be a vertical cylinder about 100mm dia and 80mm high, with two large threads on top and bottom, which will have (slightly high-tech) jamjars screwed into them. The induction coil will be inside this cylinder, with the leads passing through it.
The cylinder will be divided with a horizontal partition at the bottom with a valved hole in it for the melt to pass through, so the top and bottom jamjars can be independently evacuated/pressurised at need,
Then I can get access to the coil and the crucible inside by unscrewing the top jamjar, and access the casting area by unscrewing the bottom jamjar ( while not interfering with the atmosphere in the other jamjar).
So, any thoughts on what to make the cylinder out of? Mostly it will be fairly cool, but some bits will get hot, and of course it has to contain vacuum and/or a few bars pressure.
And it can't be electrically conductive, as that would interfere with the induction coil.
Ta,
-- Peter F
if I thought 'twere easy, I'd not ask
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wrote:

Alumina tube is available in the right sort of diameters, but is seriously
sawed and ground as a lower cost alternative. almath.co.uk seem to have both.
regards Mark Rand
--
RTFM

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"Peter Fairbrother" wrote in message
I am trying to build a vacuum investment casting machine for lost wax casting of high temperature materials (inconels and other nickel superalloys).
The heater will be induction, either a ready-bought one or one I build myself. It will melt the casting material in vacuum, then cast it under argon pressure and/or gravity into an evacuated mould.
My problem is what to make the case out of.
A rough design might be a vertical cylinder about 100mm dia and 80mm high, with two large threads on top and bottom, which will have (slightly high-tech) jamjars screwed into them. The induction coil will be inside this cylinder, with the leads passing through it.
The cylinder will be divided with a horizontal partition at the bottom with a valved hole in it for the melt to pass through, so the top and bottom jamjars can be independently evacuated/pressurised at need,
Then I can get access to the coil and the crucible inside by unscrewing the top jamjar, and access the casting area by unscrewing the bottom jamjar ( while not interfering with the atmosphere in the other jamjar).
So, any thoughts on what to make the cylinder out of? Mostly it will be fairly cool, but some bits will get hot, and of course it has to contain vacuum and/or a few bars pressure.
And it can't be electrically conductive, as that would interfere with the induction coil.
Ta,
-- Peter F
if I thought 'twere easy, I'd not ask
-------------------------------------------------------------------------------- How about a borosilicate glass (e.g. Pyrex) tube clamped between two flanges for sealing? The glass will easily tolerate gradual heating and cooling, while a wall thickness of 1/4" will resist vacuum and low positive pressure. Attaching any fittings to it would be nearly impossible however.
Clifford Coggin Kent England
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