521 Marine Grade Epoxy Resin - Quart Kit - Slow Hardener 521 Marine Grade Epoxy Resin Pro Marine Supplies
521 Marine Grade Epoxy Resin - Quart Kit - Slow Hardener 521 Marine Grade Epoxy Resin Pro Marine Supplies

521 Marine Grade Epoxy Resin - Quart Kit - Slow Hardener

Same day shipping on orders placed Mon-Fri by 4pm.

Retail Price: $49.99

Your Price: $39.99


Product Description 

Our 521 Marine Epoxy Resin can be used with our 521 fast or slow hardener, depending upon your application. 521 Marine Epoxy Resin bonds with fiberglass, metals, wood, and composite fabrics and features superb strength, durability, and moisture resistance. The 521 epoxy cures to a high-strength solid suitable for laminating, bonding, fairing, coating, and reinforcing. Pot life ranges from 12 minutes @ 75°F for Fast Hardener, to 30 minutes @ 75°F for Slow Hardener. Cures to a high-strength, moisture-resistant, light amber plastic solid that can be sanded and shaped easily, once cured. Not suitable for clear-coating applications. Self-leveling properties are ideal for coating and laminating. Viscosity is favored for wetting out fiberglass cloth and other reinforcement fabrics easily. Use this versatile epoxy resin with 521 fast or slow hardener to complete a number of boat building, repair, and restoration projects.

  • Bonds with fiberglass, reinforcement fabrics, wood, etched aluminum, and bare steel and lead
  • Its viscosity is preferred for ease of wetting out fiberglass and other fabrics
  • Makes a strong filleting or fairing compound or adhesive 
  • Excellent thin-film characteristics provide smooth flow-out and self-leveling ideal for coating and laminating
  • Easily sanded and shaped once cured
  • Easy to measure and mix using pre-calibrated 5:1 Epoxy Pumps (included), or by weight or volume
  • Easy to apply by brush, roller, syringe, spreader, or by pouring onto wood, fiberglass, reinforcement fabrics, etched aluminum, bare steel, and lead.
  • Compatibility: Pro Marine Supplies 521 Epoxy Resin can be used interchangeably with 521 Fast or Slow Hardeners
  • Kits are available in quart and gallon sizes, with your choice of Pro Marine Supplies 521 Fast or Slow Hardener. The kit comes with resin,  hardener, and pumps.
  • Note: Resin group sizes correspond to sizes of Pro Marine Supplies 521 Fast and Slow Hardeners.

Product Specifications -

  • Mix ratio by volume: 5 parts resin to 1 part hardener
  • Application: Brush, roller, or syringe; can also be poured and spread with an epoxy spreader. 
  • Minimum recommended temperature (Fast Hardener): 40°F
  • Minimum recommended temperature (Slow Hardener): 60°F
  • Recommended temperature for dispensing via pump: 60-70°F
  • Pot life @ 77°F: 12 minutes (Fast Hardener); 30 minutes (Slow Hardener)
  • 5:1 Epoxy Resin Color: Clear
  • Hardener Color: 521 Fast, Slow (amber)


521 Epoxy Resin Marine Grade 

Viscosity cPs @ 77 F - 500 ~ 700 

WPE - 195 ~ 215 

Gardner Color 1 Max. 

Density - 9.3

521 Fast Hardener 


cP @ 77 F - 100 ~ 200

Amine H+Eq. Weight - 34 

PHR - 18 

Gel Time - 13 

Density - 8.6

521 Slow Hardener 


cP @ 77 F - 200 ~ 400

Amine H+Eq. Weight - 86

PHR - 46

Gel Time - 40

Density - 8.2