PlatSil® FS-20 Silicone Rubber


PlatSil® FS-20 (Fast-Setting) Silicone Rubber is a two-part, platinum-catalyzed, liquid silicone system that cures (RTV) to a milky white, Shore OO66/A20 rubber. This product offers a simple 1A:1B mix ratio (by weight or volume), a fast demold time of ~25 minutes, and a long pour time (~8 minutes) relative to its cure speed. This allows for fast turn-around of molds and parts with sufficient time to mix and pour. Heat can be used to further accelerate the cure. 

This is a pourable rubber, but it can be easily thickened with PlatThix Liquid Thickener or Fumed Silica for brush-on application.


Current Stock:
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Technical Specifications

Mix Ratio by Volume:
Mix Ratio by Weight:
Shore Hardness:
Pour Time:
8 min.
Demold Time:
25 min.
Cured Color:
Milky White
Mixed Viscosity:
3,800 cP
Specific Volume:
24.9 in³/lb
Specific Gravity:
626 %
Tensile Strength:
467 psi
Die B Tear Strength:
148.2 pli
Die T Tear Strength:
52.8 pli
Cure Inhibition:
Contamination from sulfur (e.g., sulfur-based clay), amines, tin compounds, cured polyester resin, some paints and some silicone rubbers may inhibit surface cure of platinum-cured rubbers.

More Information

Material Calculator

Technical Bulletin

Safety Data Sheet

Kit Components
PlatSil® FS-20 Components
2-lb kit includes: 1 lb of PlatSil® FS-20 Part A (~1 pint)
1 lb of PlatSil® FS-20 Part B (~1 pint)
16-lb kit includes: 8 lb of PlatSil® FS-20 Part A (~1 gallon)
8 lb of PlatSil® FS-20 Part B (~1 gallon)
80-lb kit includes: 40 lb of PlatSil® FS-20 Part A (~5 gallons)
40 lb of PlatSil® FS-20 Part B (~5 gallons)

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