PlatSil® 73-Series Silicone Rubbers

platsil-73-seriesPlatSil® 73-Series silicone mold rubbers are soft to mid-range hardness, high-performance, room temperature curing systems. They offer excellent flexibility, toughness, and chemical resistance. Suitable for making molds of simple shapes as well as complex models with fine detail and undercuts.


  • Shore A15 to A60 hardness liquid mold rubbers
  • High-strength, long mold life formulas
  • Excellent chemical resistance
  • No shrinkage upon cure
  • Reproduces fine detail
  • Release agent not required for most applications
  • Ideal for the most demanding resin casting applications
  • Can be accelerated for rapid cure (see “Accelerators” under “Accessories”)
  • Can be thickened for brush-on or trowel application (see “Thickeners” under “Accessories”)


Typical Uses



Product Mix Ratio by Weight Shore Hardness Pour Time  Demold Time  Cured Color
PlatSil® 73-15 1A:1B A15 20 min. 4-5 hr. White Translucent
PlatSil® 73-20 1A:1B A22 5 min. 1 hr. Gray Translucent
PlatSil® 73-25 1A:1B A25 15 min. 4-5 hr. Green
PlatSil® 73-29 1A:10B A30 45 min. 16 hr. White
PlatSil® 73-40 1A:10B A40 45 min. 16 hr. Yellow
PlatSil® 73-45 1A:10B A45 60 min. 16 hr. Green
PlatSil® 73-60 1A:10B A60 45 min. 16 hr. Blue
Softener Add Silicone Fluid 50cs to PlatSil products for a lower-viscosity mix and a softer rubber.
Thickener Add PlatThix liquid thickener to thicken the liquid mix for application by brush or trowel.
Retarder Add PlatSil® 71/73 Part R Retarder to slow the cure of PlatSil products.
Accelerator Add PlatSil® 71/73 Part X Accelerator to accelerate the cure of PlatSil products.


Product Literature

PlatSil® 73-Series Technical Bulletin | PlatSil® 73-Series Physical Properties Bulletin


Video Tutorials

This video features the making of a two-piece PlatSil® 73-40 silicone block mold:


Other PlatSil® 73-Series Video Tutorials on the Polytek YouTube Channel:



Tutorials & Other Information on the Polytek Blog