Wooden Boat Restoration Repair - WEST SYSTEM Epoxy

PROBLEM POSSIBLE CAUSES SOLUTION
Clear coating turned
cloudy.
Fairing compound (epoxy/407
or 410 mixture)
sags and is difficult to
sand.
Waxy film appears on
surface of cured epoxy.
The hardener has turned
red after several years
storage.
Paint or varnish will not
set up over epoxy.
Epoxy became very hot
and cured too quickly.
Pinholes appear in epoxy
coating over
abraded fiberglass or epoxy.
Bubbles formed in coating
over bare wood or
other porous material.
Moisture from condensation
or very humid conditions
reacts with amines in uncured
hardener.
Entrapped air from aggressive
roller application.
Fairing material not thick
enough.
Amine blush forms as part
of the curing process.
Moisture in contact with
hardener and metal container.
Epoxy not completely
cured.
Paint incompatible with epoxy.
Epoxy surface not thoroughly
prepared.
Batch is too large.
Temperature too warm for
the hardener.
Surface tension causes epoxy
film to pull away from
pinhole before it gels.
Air trapped in the wood escapes
through coating
(outgassing) as the wood’s
temperature is rising.
Problem solving guide 74
1. Wash and sand cured coating to remove blush.
Cloudiness may appear in the amine blush at the
surface or throughout the coating.
2. Use 207 Special Clear Hardener for clear coating
applications.
3. Use 205 or 206 Hardeners for clear coating only
in dry conditions.
4. Use 207 Hardener for laminating thin veneers that
may allow epoxy to bleed to the surface, especially
when vacuum bagging.
1. Apply coating at warmer temperature–thinner epoxy.
2. Apply epoxy in thin coats.
1. Add more filler to the mixture until it reaches a
“peanut butter” consistency–the more filler added,
the stiffer and easier it will be to sand.
2. Allow the wet-out coat to gel before applying the
fairing material to vertical surfaces.
1. Blush formation is typical. Remove with water.
See 8.4.1 Special preparation, page 64.
2. Use 207 Special Clear Hardener, which is blush
free.
Red color will not affect epoxy performance.
May not be suitable for clear coating or in exposed
areas where color is not desired.
Allow the final epoxy coat to cure thoroughly. Allow
several days if necessary for slow hardeners at
cooler temperatures. Warm the epoxy, if possible.
1. Use a different type of paint. Some single part
polyurethanes are incompatible with the hardener.
If unsure, test for compatibility on a coated piece of
scrap material.
2. Use 207 Special Clear Hardener.
Remove the amine blush and sand the surface thoroughly
before applying paints or varnishes.
See 8.4.1 Special preparation, page 64.
1. Mix smaller batches.
2. Transfer the mixture to a container with more
surface area, immediately after mixing.
Use 206 Slow or 209 Extra Slow Hardener in very
warm weather.
After applying epoxy with 800 Roller Cover, force
epoxy into pinholes with a stiff plastic or metal
spreader held at a low, nearly flat angle. Re-coat
and tip off coating after all pinholes are filled.
1. Coat the wood as its temperature is dropping—after
warming the wood with heaters or during
the later part of the day.
2. Apply a thinner coat, allowing air to escape
easier.
3. Tip off the coating with a roller cover brush to
break bubbles.
Wooden Boat Restoration & Repair ©2008 Gougeon Brothers Inc., All rights reserved.
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