Built a vacuum table 4 yrs ago. Purschased a used HVAC air conditioner service vacuum, you can find them on Craigs list quite often. used a sheet of 1/4" aluminum for the table, drilled and tapped a hole in the center and use a sheet of red hi temp silicone gasket material for the seal. there is an additional tapped hole with a valve off to the side to be used with a plexi bell jar that I use for debubblizing investment.
In use the standard flask is filled short of the rim by 3/8 to 1/2" with a series of short holes drilled around the outside edge of the flask for additional surface area for the vacuum to draw on. do not dill more the a inch deep and watch out for the location of your wax pattern. when the flask has calcined it is placed on the gasket, the pump is started and as soon as it draws a vacuum the molten metal is poured in.
I have pictures of the table and will see if I can find them for posting.
That sounds very interesting. I would certainly love to take a look at some pictures to get a better idea of what you created here. Thanks for your input on the subject!
