Poly 74-Series Liquid Mold Rubbers

liquid-mold-rubbersThese polyurethane liquid mold rubbers are soft to mid-range hardness, high-performance, room temperature curing systems. They offer superior flexibility and toughness allowing durable molds to be made from relatively simple to the most highly detailed, undercut and complex models. The 74-Series liquid mold rubbers are supplied as pourable liquids so poured block and blanket molds can be made with ease; thickening agent can be easily added to make brush-on molds.


  • Shore A20 to A55 hardness liquid mold rubbers
  • High-strength, abrasion-resistant, longest lasting molds
  • Reproduces fine details
  • Pourable or brushable (see “Thickeners” under “Accessories” for brushing)
  • Can be accelerated for rapid cure
  • Economical & versatile
  • Ideal for the most demanding mold making applications
  • All rubbers can be demolded after ~16 hours


Typical Uses


Product Options

Product Mix Ratio Shore Hardness Pour Time Cured Color
Poly 74-20 1A:2B A20 30 min. Yellow
Poly 74-24 1A:1B A25 20 min. Amber
Poly 74-29 1A:1B A30 30 min. Black or White
Poly 74-30 1A:1B A30 25-30 min. Amber/Varies
Poly 74-30 HT 1A:1B A30 25-30 min. Amber/Varies
Poly 74-30 Clear 1A:1B A30 25-30 min. Transparent Amber
Poly 74-40 2A:1B A40 20 min. Varies
Poly 74-41 1A:1B A40 20 min. Varies
Poly 74-44 2A:1B A45 20 min. Gray
Poly 74-45 1A:1B A45 30 min. Yellow
Poly 74-55 4A:1B A55 15 min. Amber
Softener Add Poly 74/75 Part C Softener to 74-Series products for a lower-viscosity mix and a softer rubber.
Accelerator Add Poly 74/75 Part X Accelerator to 74-Series products to accelerate the cure.
Thickeners Use PolyFiber II or Fumed Silica to thicken the liquid mix for application by brush or trowel.
UV Stabilizer Use UV additive to help reduce the characteristic surface degradation caused by sunlight.
Reinforcement Materials for Blanket Molds Use Tietex® Fabric to reinforce blanket molds.
Product Life Extender Use Poly Purge Aerosol Dry Gas to extend product life by spraying it into containers before resealing.


Product Literature

74-Series Technical Bulletin | 74-Series Physical Properties Bulletin


Video Tutorials

Watch how to make a veneer stone mold with Poly 74-20:


Other 74-Series Tutorials on the Polytek YouTube Channel:


Tutorials & Other Information on the Polytek Blog