Each of our 3 automated, vertically parted, high-pressure green sand molding machines are custom-designed, built and maintained in-house. They’re not really green, but that’s the term used for sand that has not been used for a mold. Why sand? It’s all in the chemistry.
Iron melts at about 2,800 degrees Fahrenheit. Sand won’t melt until the temperature is roughly 3,000 degrees, making it a perfect holder for molten iron. But at Poitras Foundry, sand alone won’t stand up to the pressure and heat of making quality castings.
Our green sand is made of:
-Silica sand to act as an insulator
-Clay or Bentonite used to bind the sand grains together and form a mold that won’t break down
-Filler material such as cereal or wood flour that will fill the spaces between sand grains
-Seacoal, which is a fine dust, adds carbon between sand grains to prevent oxidization by reducing atmosphere in the mold
Green sand molding provides a variety of advantages for our customers:
-Lower cost compared to other casting processes
-Provides a variety of molding processes to suit specific volume and quality requirements
-Ability to produce both prototype and production volumes with the same process