Poly 77-Series Liquid Mold Rubbers

poly-77-seriesThese polyurethane liquid mold rubbers are mid-range to firm hardness, high-performance, high elongation, room temperature curing systems. Although 74-Series & 75-Series liquid rubbers are our most popular mold rubber options, the two options in the 77-Series are sometimes chosen for the following reasons: They offer lower viscosity and higher elongation than rubbers of the same hardness in other series.


  • Shore A50 and A65 hardness liquid mold rubbers
  • Low-viscosity, pourable rubber so poured block and poured blanket molds can be made with ease
  • High-strength, abrasion-resistant, high elongation rubbers
  • Reproduces fine details
  • Long-lasting, economical
  • Rubbers can be demolded after ~16 hours


Typical Uses

  • precast concrete pavers, slabs, retaining wall blocks and other cast stone applications
  • flexible formliners
  • concrete countertop forms
  • molds for architectural GFRC and restoration applications
  • numerous general mold making & casting projects with casting materials including plaster, wax and resins
  • View more applications in the 77-Series Product Photo Gallery (gallery also includes 75-Series & 81-Series rubbers).


Product Options

Product Mix Ratio Shore Hardness Pour Time Cured Color
Poly 77-50 1A:1B A50 15 min. Tan
Poly 77-65 1A:1B A65 15 min. Tan
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.
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

77-Series Technical Bulletin | 77-Series Physical Properties Bulletin