Hi Orchid Community,
My name is Max Goodman, I run the jewelry program at a community art
studio called 3rd Ward in Brooklyn, NY. Currently, we run a lost wax
casting class. We cast using a Vigor brand vacuum chamber from the
1940s that belongs to a coworker. When we first got the vacuum in the
shop we ran a test cast by pouring manganese bronze into our flasks
at 900 degrees farenheit. Our test cast was successful, and following
that we have had mixed success. Lately, we’ve had an extremely low
success rate, though as far as I can tell nothing has changed. Our
vacuum has a knob that points either towards the investment table or
the casting chamber, but it seems to add suction to both regardless
of where the knob is pointing, and it doesn’t release until we turn
the motor off, even if the knob is positioned on the release setting.
Though the guage reads at its maximum setting while casting (30 psi)
it seems to me that the metal is not being vacuumed properly into the
moulds, and this is what is causing our failed casts. We have tried a
number of metals, including sterling silver and a new
lower-melting-temperature bronze that is designed for pour casting,
and raising the temperature on the flasks in the kiln, nothing seems
to make a difference, so I’m turning to you Orchid Community. Here
are my questions:
Do you know of a place where I can get a vacuum repaired,
preferably near New York City?
Can you think of any human errors I might be making that I have
not thought of?
Do you know any tricks for successful vacuum casting?
I await your knowledgeable answers, and thanks in advance for your
thoughts and help!