Platinum Silicone Mold Rubbers

platinum-silicone-mold-rubbersPlatSil® platinum silicone mold rubbers consist of two parts (Part A & Part B), which, after mixing, cure at room temperature to flexible, high-strength rubbers. Platinum silicone mold rubbers are sometimes preferred over tin silicone rubbers because they do not shrink on cure and have a longer library life.


  • Do not exhibit shrinkage upon curing so they are useful for casting dimensionally stable parts for highly accurate prototyping and model making applications.
  • Do not require release agents when casting most materials.
  • Cured molds have a long library life.
  • These rubbers can be poured as supplied or thickened with PlatThix liquid thickener for brush-on molds.


Typical Uses & Casting Materials

  • Resin casting (polyurethane, polyester, epoxy)
  • Foam casting
  • Wax casting
  • Sculpture reproduction
  • Soap and candle making
  • Plaster casting
  • Cold cast bronze art


CAUTION: Care should be taken to ensure objects that come in contact with PlatSil® liquid rubbers are not contaminated with amines, sulfur, tin compounds and others which may inhibit the cure of the system.

There are three series within the platinum silicone mold rubber line:

Platinum Silicone Rubbers

PlatSil® 71-Series 8 individual product options. Shore A10 to A40 hardness range. Includes one translucent rubber option. 1A:1B, 1A:10B, and 1A:5B mixes available. Demold times ranging from 30 minutes to 24 hours. SiliGlass (a rubber that shatters like glass – for spfx) & SiliFoam (a soft, silicone foam) are included in this series.
PlatSil® 73-Series 7 individual product options. Shore A15 to A60 hardness range. Includes two translucent rubber options. 1A:1B and 1A:10B mixes available. Demold times ranging from 1 hour to 16 hours.
PlatSil® Gels 3 individual product options. Soft, skin-safe, translucent rubbers for delicate casting projects, including theatrical prosthetics and special effects. Shore OO30, A10 & A25 hardness.


Video Tutorials

This video features the making of a two-piece PlatSil® 73-40 (in the PlatSil® 73-Series) block mold of a resin figure:


Other Platinum Silicone Rubber Video Tutorials on the Polytek YouTube Channel: