Plastisol Casting

Fried Egg - Plastisol Casting of Fridge Magnet
Cookie - Plastisol Casting of Fridge Magnet
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Plastisol Casting by Piper Plastics Corp.

A process used to develop products like refrigerator magnets and vehicle bumpers, plastisol casting is a cost-effective casting method that can vary based on the product being produced. 

Open mold casting and slush casting (also known as slush molding) are the two plastisol casting methods we at Piper Plastics specialize in. 

Open Mold Casting Steps

Since plastisol is primarily a suspension of PVC particles in a liquid plasticizer, it flows as a liquid and can be poured into a open mold.

  1. When the mold then gets heated to the proper temperature, the PVC resin swells and begins to absorb the plasticizer.
  2. After cooling the mold, a flexible, permanently plasticized solid product results.

Because of the open mold, this process is good for items with a “flat” bottom. Common examples include:

  • Refrigerator magnets
  • Key tags
  • Door mats

Slush Molding

The second plastisol casting process that we specialize in is slush molding. A more complex casting option than open mold casting, slush molding is a cost-effective alternative to injection molding that can be used to develop some plastic products. 

Metal molds are used when slush casting, as these molds are not affected by heat and can allow for a faster production time than flexible mold alternatives. Metal molds are able to be used over and over again, making them a major asset to the product manufacturer. 

  1. Open mold cavities are filled with plastisol. 
  2. The mold is spun on a centrifuge, forcing the plastisol to fill all the spaces within the mold. 
  3. Mold is placed in a heating solution at 400 °F for a few seconds.
  4. Once a gel-like layer of plastisol has formed within the mold, the mold is removed from the heat, and the still-liquid plastisol is emptied from it. 
  5. Mold is placed back in the heat to cure.
  6. After about three minutes, the mold is removed again and put in water to cool.
  7. Once cooled, the vinyl piece can be removed from the mold. As it cools it will go from a flexible form to a rigid final piece.

Here at Piper Plastics, we provide a variety of custom casting services, including:

  • Intricate & Complex Shapes
  • On-Site Pattern & Tool Development – Saves Time/Money
  • CAD/CAM, SPC/SQC to Custom Specs
  • All Colors, Textures & Durometers
  • FDA / USP /Automotive Materials
  • Thickness from .031″ to 12″