When casting, the machine creates a vacuum at one end of the flask, which pulls the air and gases from the mold so that the molten metal flows quickly to every opening. Larger flasks can be cast with vacuum casting than with the centrifugal machine (although it is not possible to specify exact sizes, as the amount of metal to be cast, the shape of the cavity, etc., will all affect the size). This machine is capable of creating a negative mercury pressure equal to 27"-29" at sea level. The vacuum table measures 10-1/2" x 10-1/2" and rests on jiggle springs. Unit comes complete as shown. Shipping weight 50 lbs.