Epoxy Resin Guide
Using Epoxy Resins
Product Selection Chart
 This Product/Application Overview shows how bonding, fairing and coating applications are related to combinations of specific products in our 105 Resin-based line.
Step 1
Start with 105 Resin, the basic ingredient of all WEST SYSTEM epoxy compounds. Use 300 Mini Pumps for convenient and accurate metering.
Step 2
Mix with one of four WEST SYSTEM hardeners.
Select a hardener for its intended use and for the cure speed best
suited for your job in the temperature range in which you are working.
Step 3
Add one of six WEST SYSTEM fillers
to thicken the mixture as needed. Select a filler for its handling
characteristics or cured physical properties. Or, add one of four WEST
SYSTEM additives to provide specific coating properties.
See An Overview of WEST SYSTEM Epoxies for a summary of information on the 105 Resin system, G/flex Epoxy, Six-10 Thickened Epoxy Adhesive and G/5 Five Minute Epoxy.
Versatile
Building and Repair Product
Epoxy resin, used in conjunction
with its companion fillers, fabrics and tools, is one of the most versatile
materials available for boat repair and construction. Epoxy-based resins owe
their broad acceptance, by pros and amateurs alike, to the fact that they allow
you to tackle such a wide variety of projects. Whether you want to repair gel
coat cracks or a delaminating deck, install a bulkhead or even cold-mold a
brand-new hull, you can create an epoxy mixture with the precise
characteristics you need.
Key
Applications
Epoxy uses fall into a few core
categories:
- Coating,
where you apply one or more thin coats of epoxy to seal a surface or to
prepare the surface for varnish or reinforcing layers like fiberglass or
carbon fiber.
- Bonding,
where you use the epoxy as a glue, generally with some filler to allow it
to fill gaps between the surfaces, or to attach hardware to a surface.
- Laminating,
where multiple layers of wood or other materials are laid up to create a
thicker solid structure.
- Fairing,
where thickened resin is used to fill holes and depressions so that the
surface can be sanded and smoothed.
Note that while many applications
involve wood, epoxy resin can be used on fiberglass, carbon fiber, metals, etc.
How
They Work
The heart of working with epoxy is
the basic epoxy resin, combined with one of several hardeners. The clear amber
resin cures to a high-strength plastic solid at room temperatures when mixed
with specific proportions of the correct hardener. Hardeners are selected by
the ambient temperature (which results in a reasonable “pot life”), or by a
desired characteristic of the resulting mixture (like extra clarity for a clear
finish in the case of WEST SYSTEM’s 207 Hardener.)
Mixing
the Epoxy
The heart of working with epoxy is
the basic epoxy resin, combined with one of several hardeners. The clear amber
resin cures to a high-strength plastic solid at room temperatures when mixed
with specific proportions of the correct hardener. Hardeners are selected by
the ambient temperature (which results in a reasonable “pot life”), or by a
desired characteristic of the resulting mixture (like extra clarity for a clear
finish in the case of WEST SYSTEM’s 207 Hardener.)
To make it easier to buy, the right
amount of resin and hardeners are packaged in group sizes. For each
container size of resin, there is a corresponding container size of hardener
like WEST SYSTEM Group A or Group B.
Modifying
the Epoxy Mixture
Because unmodified epoxy is both
expensive and has low viscosity, you frequently add fillers or additives to
create the right blend of properties for the job. Fillers are designed to
thicken the epoxy mixture and are broadly grouped into two categories: High
Density and Low Density.
High Density fillers are used to modify the structural properties of the epoxy
by adding strength, bulk or both. Examples include WEST SYSTEM’s #404 and #406.
High density filler mixtures cure to a strong, hard-to-sand plastic useful in structural
applications like bonding, filleting and laminating.
Low Density fillers cure to a light, easily-sanded material which is often used
for cosmetic or surface applications such as shaping or fairing. Examples
include WEST SYSTEM’s #410 and #407.
Additives alter the physical properties when the epoxy mixture is
used in coating applications. Barrier coat additive (#422) improves the
effectiveness of the basic epoxy/hardener mixture at resisting moisture
penetration. Adding graphite powder (#423) makes coated surfaces slick, which
can be used on rudders, centerboards or centerboard trunks. Aluminum powder
(#420) can be used to prevent UV deterioration. Unlike additives and fillers, reinforcing
materials are not mixed with the epoxy, but are often used in conjunction
with the epoxy mixture to provide additional physical properties.
Safety
Like many other boat maintenance
materials, epoxy resin products should be applied carefully. Please refer to
the wide selection of books, manuals and DVDs on the uses of epoxy resins, for
information on how to use them safely.
In
Conclusion
We’ve found that using epoxy resin
products has added a whole new dimension to our boat repair skills. We feel
empowered to take on projects that we would have formerly delegated to a boat
yard or boat maintenance worker. Resin has many additional applications at home
when it comes to reinforcing furniture, patching surfaces, and other repairs.
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