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Product Details

Entropy Clear Slow Hardener (CLS) is used to extend working properties and cure time when mixed with Entropy Clear Laminating Epoxy Resin (CLR) or Optically Brightened Laminating Epoxy Resin (BRT) for laminating wood, fiberglass, carbon fiber, or Kevlar. These premium resins are used for hand layup, room-temperature processes, or infusion laminating.

This biobased resin system exhibits low color, excellent air release, and exceptional UV and color stability. Use with CLR resin or BRT resin for long pot life and low exotherm lamination and coatings. Resin and hardener combined have a bio-content greater than 30%, and can be modified with epoxy compatible colorants and fillers.

Requires corresponding size of Clear Laminating Epoxy Resin (CLR) or Optically Brightened Laminating Epoxy Resin (BRT - bright white) for use (2:1 mix ratio). See chart below.

Tech Specs
Specifications & Mechanical Data Entropy CLR/CLS Admixed Entropy BRT/CLS Admixed
Color Clear White
Mix Ratio by Volume 2:1 (resin:hardener) 2:1 (resin:hardener)
Mix Ratio by Weight 100:47 (resin:hardener) 100:47 (resin:hardener)
Mixed Viscosity @ 77°F 800 cPs 800 cPs
Pot Life @ 77°F 43 minutes 43 minutes
Tack-Free Time @ 77°F 8 hours 8 hours
Ideal Working Temperature Range Optimal - 70-85°F; Extended - 60-95°F Optimal - 70-85°F; Extended - 60-95°F
Ideal Working Humidity Range Optimal - 0-40%; Extended - 0-85% Optimal - 0-40%; Extended - 0-85%
Recommended Full Cure 7 days @ 77°F; post cure recommended 7 days @ 77°F; post cure recommended
Tensile Strength 9,800 psi 9,800 psi
Elongation 6% 6%
Flexural Strength 14,580 psi 14,580 psi
Compression Strength 12,520 psi 12,520 psi
Tg Ultimate 171°F 171°F
Hardness, Shore D 70-80 70-80
Entropy CLR or BRT Laminating Epoxy Resin Quantity Clear Slow Hardener (CLS) Quantity Mixed Quantity
32 oz.16 oz. hardener48 oz.
1/2 gallon resin1 qt. hardener3 qt.
1 gallon resin1/2 gallon hardener1.5 gallons
2 gallons resin1 gallon hardener3 gallons
5 gallons resin2.5 gallons hardener7.5 gallons
Info & Guides

NOTE: Exact fill weight of 5 Gallon CLS Hardener is 5.139 gallons.

Technical Information

Features of Clear Slow Hardener (CLS) Combined with CLR Resin or BRT Resin

  • Slow hardener for Entropy's high-performance, CLR clear epoxy resin, or bright white BRT epoxy resin.
  • Green epoxy resin with longer pot life and a slower room temperature cure than CLF (fast) or CLX (Extra Fast) hardeners.
  • Excellent composite laminating resin ideal for hand layup and vacuum bagging.
  • Great for high-color applications requiring a clear, non-yellowing resin system.
  • UV-stable formula with relatively low viscosity.
  • First USDA BioPreferred Certified liquid epoxy resin system.
  • CLS requires corresponding size of Entropy CLR Epoxy Resin or BRT Epoxy Resin for use (2:1 mix ratio). See chart below.

Entropy Clear Slow Hardener (CLS)/Clear Laminating Epoxy Resin (CLR) System Best Uses

  • Surfboards, SUPs (stand up paddleboards), handplanes
  • Adhesives and sealants
  • Fiberglass boat repair
  • Clear coating applications
  • Natural fiber composites
  • Carbon fiber composites
  • Fiberglass composites

Entropy Optically Brightened Laminating Epoxy Resin (BRT)/Clear Slow Hardener System Best Uses

  • White surfboards
  • Bright white cosmetic marine laminating applications

Safety and Handling Information

Despite the natural derivation of Entropy resin products, exposure to these materials represents hazards typical of all epoxy resins. Exposure should be minimized and avoided through the use of proper personal protective clothing & equipment, and appropriate manufacturing controls. All persons who use, store, or transport these materials should understand proper handling precautions and recommendations, as stated in the SDS (safety data sheets).