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Thomas M. Sandretto, Inc.

   We designed and managed the manufacture of our own investing machine.  There are two chambers.  After mixing powder and water the investment slurry is poured into the top chamber where it is placed under very low pressure by the use of a very strong vacuum pump.  The low pressure removes entrapped air bubbles from the mix.  After a specific period of time the slurry is metered through a ball valve into the bottom chamber where up to eight 4 1/2" X 8" stainless steel flasks are placed on a turntable.  Each flask surrounds an assembly of wax patterns made up into trees.  Low pressure is maintained for a total working time of about nine minutes to insure that no air bubbles remain clinging to the wax patters.  An trapped air bubble in the investment material results in a sphere of cast metal when the flask is filled with molten metal.  Normal atmospheric pressure is then allowed back into the lower chamber prior to the investment material setting up.   After a quick rinse with clean water our investing machine is ready to handle another eight molds.

This photograph shows molds poured using our investing machine.

  In addition to gas melting in a crucible furnace there are times when we melt and cast using our medium frequency vacuum assist gravity pour casting machine.  This machine works very well and has stood the test of time for us.

    Our capacity is about 32 molds per furnace.  Each mold is 4" X 8.5" and is burned out overnight to a maximum temperature of 1350F.

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Copyright 1974 - 2010 Thomas M. Sandretto, Inc.    Last modified - December 19, 2010

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