The Gougeon Brothers on Boat Construction - WEST SYSTEM Epoxy

8 Fundamentals of Wood/Epoxy Composite Boatbuilding
epoxy polymers are complex molecules of multidirectional,
interlocking chains. <strong>The</strong>se chemical characteristics
give the cured epoxy physical properties in its own
right. In general, epoxies have greater strength, less
shrinkage, better moisture resistance, better resistance
to fatigue, and are less flammable than polyesters.
Epoxies are also excellent bonding agents for a wide
variety of surfaces.
WEST SYSTEM ® Epoxy
This book specifically recommends the use of WEST
SYSTEM epoxy in all manufacturing. While this may
appear to be self-serving, the fact is that our instructions
would be of little value if the bonding and sealing
materials, which are central to our method of boatbuilding,
were not discussed in detail. WEST SYSTEM
epoxy is a versatile, high-quality, two-part epoxy that
is easily modified for a wide range of coating and
adhesive applications. It is used for construction and
repairs requiring superior moisture resistance and high
strength. It bonds to fiberglass, wood, metal, fabrics,
and other composite materials, and is especially suited
for marine applications.
Epoxy brands can vary widely in their formulations,
quality of raw materials, and suitability for marine
environments. It’s easy to market an off-the-shelf industrial
epoxy product as a marine epoxy or formulate an
epoxy with one or two favorable characteristics while
sacrificing other important characteristics. It’s much
more difficult balancing all of the physical and mechanical
properties necessary for a versatile, high-quality
marine epoxy. Defining an epoxy’s performance criteria
and designing a formula to meet those criteria require
good chemistry, rigorous test programs, skillful shop
work, and direct experience with high-performance
boats and other composite structures.
Since 1972, <strong>Gougeon</strong> <strong>Brothers</strong>, Inc. has tested potential
resin and hardener formulas, ingredients, and combinations
to compare fatigue strength, compression strength,
glass transition temperature, and peak exotherm. Additionally,
our materials test lab tests qualified samples for
hardness, tensile strength, tensile elongation, tensile
modulus, flexural strength, flexural modulus, heat
deflection temperature, impact resistance, and moisture
exclusion effectiveness.
Figure 2-1 Formulating a high-quality marine epoxy requires
a balance of performance criteria.
Our testing not only supports in-house product development;
we also conduct tests to support outside builders,
designers, and government organizations in the engineering
of epoxy composite structures. Aside from a battery
of standard ASTM tests, <strong>Gougeon</strong> <strong>Brothers</strong> has developed
some new testing methods to evaluate adhesives
and composites, including the patented Hydromat Panel
Test, to simulate the pressure loads a section of a hull
would endure in a lifetime on the water. Over the years,
improvements in our products and in their application
Figure 2-2 Setting the MTS test machine controller in the
<strong>Gougeon</strong> materials test lab.