I have a new project.
Transform a vacuum machine in a casting vacuum machine myself. Does
anyone have suggestions?
Vlad R. Poenaru - from sunny Brazil.
Vlad,
I’ve done exactly that. Started with the vacuum pump and just
ordered the replacement parts from Rio, or any other jeweler’s
supply. The parts I ordered: the 3 way valve (to switch between the
casting side and the debubblizing side or neither), the little “trap”
(to catch any loose investment), and a pressure gauge. It’s really a
pretty simple project. I fabricated a metal box…but it could just
as easily been made with wood, I guess.
INSIDE view of homemade vacuum casting machine. This shot shows the
“TRAP” on the right side, and you can see it WORKS 
Never said it
was pretty LOL.
Bill Roberts
Hi Vlad:
Two questions:
(A) What kind of vacuum pump do you have? (Rotary or vane?) Do you
happen to know what the displacement, and ultimate pressure are?
(B) What kind of casting machine do you want?
I’ve made a variety of casting, investing and vacuum systems out of
various old pumps, but it’s helpful to know the starting point and
end goal first.
Regards,
Brian Meek.
Hi Bill:
Now that you’ve built it, most of those parts, even the 3-way valve,
are available at better hardware stores. In California, OSH used to
stock them before the beancounters gutted the place. (Sorry) (They
even had vacuum gages.)
Meanwhile, might I make a suggestion? In the detail picture, it
looks like your trap is a glass bottle. It might be safer and more
efficient to replace that with a trap built out of a short section
of black iron gas pipe. I did that to the vacucast out at school.
(The new ones don’t come with a trap anymore, so you’re stuck
rebuilding a brand new machine, just to get it up to spec. Right
out of the box. Gurr…) The reason I suggest replacing it is: hot
metal plus cold glass equals broken glass and hot metal all over the
guts of your machine. Annoying and possibly very expensive. With the
black iron pipe version, you just unscrew the bottom, pull the slug
of metal, screw the end back on, and you’re back in business.
FWIW,
Brian.
In California, OSH used to stock them before the beancounters gutted the place.
Don’t know much about the vacuum caster part, but if you need small
appliance parts of all kinds, there is a company called Appliance
Sales & Service Co.
Their store here in San Francisco (sure they do mail order) is:
http://www.thegourmetdepotco.com
All the belts, knobs, switches and doodads from appliances of all
kinds - small appliances more than large ones (washing machines…)
It’s also a good place for stuff like heat proof wiring, like in
toasters and vulcanizers… Vast…