Centrifugal vs vacuum casting

Here’s another question about lost wax casting (which I’m just
getting into): is centrifugal casting a superior and/or more
economical method than vacuum casting for small one-of-kind pieces
(or prototypes)?

I read that you might as well do vacuum casting because in any case
you need to buy an investing table and bell jar (at a minimum) for
debubblizing; so you may as well use it for casting as well and save
the cost of a centrifugal caster. However, Kerr centrifugal casters
are readily available on eBay, often for less than $100. Many
dentists seem to get along fine debubblizing with an inexpensive
vibrator. Or you can buy a neat little rubber investment mixing
device with a cover that has a mixing paddle operated by a hand crank
and an inlet in the top for a line to a vacuum pump (which could be
very small given the size of the container). These devices go new for
a little over $100 and small vacuum pumps are readily available from
eBay. The application would be making a sterling silver prototype
(or one-off piece) instead of production casting.

Any comments on this alternative to conventional vacuum casting
(which utilizes a $250 table and bell jar)?

Russell Trenholme

Hello Russell; where did you see the investment mixer for vacuum?

where did you see the investment mixer for vacuum? Kerr? 

They are made by Keystone in New Jersey. They have been largely
displaced I think by motorized mixer/vacuum devices. However, here’s
a link:

http://www.dentallabservices.com/index3.htm They’re shown at the
bottom of the page. I saw one on eBay grouped with a Kerr Centrifugal
caster and a vibrator. I think they are normally held on the vibrator
while the stirring is going on. My dentist says he just uses the
vibrator and hand mixes without a vacuum and has no problems! But
these bowls look like a good idea for small molds and certainly
wouldn’t require a very powerful vacuum pump.