PlatSil® 71-Series Silicone Rubbers

platsil-71-seriesPlatSil® 71-Series platinum silicone mold rubbers are soft to mid-range hardness, high-performance, room temperature curing systems offering excellent flexibility and toughness. Molds can be made from relatively simple models as well as highly detailed, complex models with undercuts.


  • Shore A10 to A40 hardness liquid mold rubbers
  • High-strength, long mold life formulas
  • Release agent not required for most applications
  • Excellent chemical resistance
  • No shrinkage upon cure
  • Reproduces fine details
  • Pourable & brushable (see “Thickeners” under Accessories for brushing)
  • Can be accelerated for rapid cure (see “Accelerators” under Accessories)
  • Ideal for the most demanding resin casting applications


Typical Uses

  • resin casting (e.g., polyurethane, polyester, epoxy)
  • foam casting
  • plaster casting
  • prototyping applications
  • art foundry wax casting
  • sculpture and décor reproduction
  • PlatSil® SiliGlass is designed for making super-clear, glass-like rubber castings for special effects and prop applications. Acts and looks like broken glass when hit.
  • hobby, craft, prop and display mold making and casting projects
  • view more applications in the Silicone Rubber Photo Gallery (gallery also includes 73-Series, 70-Series & 80-Series rubbers).


Product Options

Product Mix Ratio by Weight Shore Hardness Pour Time  Demold Time  Cured Color
PlatSil® 71-10 1A:10B A10 5 min. 30 min. Pink
PlatSil® 71-11 1A:1B A10 20 min. 4 hr. Blue-Green
PlatSil® 71-20 1A:1B A20 25 min. 4 hr. Light Purple
PlatSil® 71-30 1A:10B A30 60 min. 24 hr. Light Green
PlatSil® 71-35 1A:10B A35 60 min. 24 hr. Blue
PlatSil® 71-40 1A:5B A40 60 min. 24 hr. Translucent
PlatSil® SiliGlass 1A:1B A40 5 min. 30 min. – 1 hr. Clear
PlatSil® SiliFoam 1A:1B N/A N/A 30 min. Milky White
Softener Add Silicone Fluid 50cs to PlatSil products for a lower-viscosity mix and a softer rubber.
Thickener Add PlatThix 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® 71-Series Technical Bulletin | PlatSil® 71-Series Physical Properties Bulletin


Video Tutorials

This video (Part I in a two-part series) features the making of a one-piece PlatSil® 71-20 block mold:


Other PlatSil 71-Series Video Tutorials on the Polytek YouTube Channel:you-tube


Tutorials & Other Information on the Polytek Blog