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General Purpose Hardeners

System Three General Purpose Epoxy is our original product. It actually gave the company its name. From the founding of the company until just a few years ago it has been the workhorse of the product line. The system formulation, containing one resin and three curing agents or hardeners contains a significant amount of renewable materials. Long before "green” was in vogue the System Three General Purpose Epoxy System contained as much as 30% plant derived materials and has never contained any volatile organic compounds (VOC).


General Purpose Hardeners

General Purpose Resin is a versatile, all-around epoxy resin system used in both marine and woodworking applications. Three different hardeners offer performance across a broad spectrum of environmental conditions.

General Purpose Resin wets out fiberglass cloth very well and can be mixed with various fillers to create non-sagging adhesives, filleting and fairing compounds for marine applications.


• Economical without sacrificing performance

• Non-brittle, flexible film

• Combine with silica thickener to make a general duty adhesive

• Use with System Three Epoxy Pigment Concentrates for woodworking applications

• Features a convenient 2:1 mixing ratio

• 0 VOC


One Resin, Three Hardeners, Endless Possibilities

Formulated to perform in any environment

Buy in kits or individually

The Flexibility to do it all

Finding the Right Hardener

General Purpose Epoxy FAQ

The final properties of the cured General Purpose Epoxy will be equal no matter which General Purpose Hardener is used. Choose which hardener to use based on your working temperatures and desired working time. Here is a general guideline to follow.

#1 Fast Hardener: 35° F (2° C) to 60° F (15° C).

#2 Medium Hardener 60° F (15° C) to 80° F (26° C).

#3 Slow Hardener 80° F (26° C) and warmer.

Some epoxy resins are prone to blushing in cold and damp conditions. Blush is a greasy feeling surface feature that can occur when the epoxy reacts with atmospheric moisture as it is curing. Blush, being water soluble and strictly on the surface can easily be removed by washing the epoxy with warm soapy water after it has cured.

To avoid the extra step of removing any blush, some epoxy formulas are specifically formulated to be blush free in any conditions. Our blush free epoxy products are; SilverTip Epoxy, Clear Coat Epoxy, and Cold Cure Epoxy.

Homebrewing your own epoxy compounds instead of using the SilverTip line of ready-to-use epoxy compounds involves mixing various fillers into a mixed batch of one of our liquid epoxies. Below are some guidelines for creating common compounds using System Three General Purpose Epoxy, Cold Cure, SilverTip Epoxy, Clear Coat, and SB-112 Liquid epoxies.


1 cup of Silica Thickener to 6 oz of mixed epoxy.


3/4 cup of Wood Flour to 6 oz of mixed epoxy.

Fairing Compound:

1/2 cup of Silica Thickener + cup of Glass Microspheres to 6 oz of mixed epoxy.

Filleting Compound:

1 cup of Wood Flour to 6 oz of mixed epoxy.

Playdough-like Putty:

3 cups of Glass Microspheres to 6 oz of mixed epoxy.

For further detail on mixing and applying compounds, please refer to the System Three Epoxy Book.