I am interested in buying a vacuum casting machine. The
choices have confused the heck out of me. I would like to be able
to cast perforated flasks but I'm not sure if I really need that
high-tech of a machine.
If you are doing small flask, smaller than say 2Dx3h, you don’t need
a perforated flask. My machine has just a flat table with a 1/4" hole
in the center for the vacuum, and a silicon rubber gasket. I have
cast flask up to 4’d with this. The one thing I do to prepare the
flask for the casting table is to carve a concave surface in the
investment and then carve a couple troughs that cross in the center.
That way, I get a “Pull” on the full surface of the flask, not just
where the vacuum hole happens to align with it. I mostly cast 14K
with only on or two pieces, and have had very good luck with this
setup. I think that doing large trees though that the perforated
flask is the way to go.