Poly 74-30 Liquid Rubber

poly-74-30Poly 74-30 is a 1A:1B mix, A30 hardness, liquid polyurethane rubber that can be demolded in ~16 hours. This liquid rubber is great for making molds for casting materials such as concrete, plaster, resins (polyurethane, polyester, epoxy – with proper release agents), and wax. This rubber is used extensively by art foundries and individual artists for making molds for sculptural reproduction in wax (for hot bronze) or for bonded bronze casting.

There are two other variations of Poly 74-30 available: Poly 74-30 Clear & Poly 74-30 High-Tear (HT). Poly 74-30 Clear has the same physical properties as Poly 74-30, but cures to a transparent amber color instead of an opaque amber color. Poly 74-30 HT offers higher tear and tensile strength compared to the standard Poly 74-30.

Poly 74-30 molds can be poured as supplied or brushed-on by mixing in Poly Fiber II thickener or Fumed Silica. For brush-on application, 74/75 Part X accelerator can be used to speed the process.


Mix Ratio Shore Hardness Pour Time Cured Color Mixed Viscosity Specific Volume Demold Time
1A:1B A30 25-30 min. Amber/Varies 2,000 cP 27.5 in³/lb ~16 hr.
Accessories: 74/75 Part C Softener, 74/75 Part X Accelerator, PolyFiber II Thickening Agent, UV Additive, Tietex® Fabric, Poly Purge Aerosol Dry Gas


Product Literature: Technical Bulletin | Safety Data Sheets | Physical Properties Bulletin | Sealer & Release Agent Selection Guide

Video Tutorials: For 74-Series video tutorials, visit the 74-Series page or the Polytek YouTube Channel.


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