Before we get carried
away with how wonderful epoxies are we need to bear in mind that there
are some and
there is a growing concern among the
scientific community about the
health and environmental risks of traditional petrolium based
are hard therefore
brittle. There are
additives which will make them less so but these will reduce their
points. So it is best not to use them on anything which needs to flex,
as sheathing a carvel boat.
will deteriorate under
prolonged exposure to UV
light (sunlight). Even clear epoxies will yellow. So they will need to
they cure a waxy coating
(blush) will form on the
surface. This needs to be completely removed before over-coating with
anything. Nothing will stick to the wax.
another layer of epoxy this is
best done after hardening but before it has fully cured.
contamination of the
wood such as oil, wax or
moisture will prevent the epoxy soaking in. This can result in the
planning a big
project involving epoxy
resin make sure that you are not allergic to it.
never used to bother me
but I now find that while
I’m ok doing small jobs, prolonged exposure leaves me with a skin
rash and I have occasionally felt quite ill.
After application and during the curing process,
epoxy resin releases a wax-like’ film onto the surface called ‘Amine Blush’.
This amine blush will prevent subsequent layers
of epoxy and other products fully adhering unless removed properly.
The best way to reduce blushing is to work
in warm temperatures (the epoxy sets up fast, reducing the blush window) and
with humidity at low levels.
It would be best to avoid conditions where
moisture is coming out of the air as temperatures fall.
Amine blush is water soluble so, thoroughly
washing the cured epoxy with clean warm water, soap, and a stiff brush or
Scotch-Brite™ pad is the only way to completely remove it.
Sanding before removing the amine blush may
sand the blush deeper into the surface making it much harder to remove.
Even those products labelled as ‘amine
blush free’ or ‘no blush formula’ are best washed.
Solvents like Acetone will not remove the
If there is a good reason not to get your
project wet, you can use West System’s “Peel Ply”.
Peel ply is a finely woven nylon fabric
that will not bond to epoxy, however, the amine blush forms on the peel ply,
not on your cured epoxy.
Simply follow the instructions to apply
peel ply, ensure that the peel ply is thoroughly wetted out, let your epoxy
cure and then remove the peel ply once cured and before applying the next
coating, the blush will have formed on the peel ply not on the epoxy below.
Another advantage to using peel ply is that
it’s fine woven pattern is impressed into the epoxy coating, creating a ready
to bond to, graded, textured surface.
come in two
parts, the resin and a hardener
ratios will vary
from one product to the
is always best to stick
to the recommended
ratios. However curing times can be altered by altering the ratio. But
beware some products are less forgiving than others.
must be thorough.
working time (pot
life)is the interval after
mixing during which the epoxy can be applied. This will vary according
the product used.
mix the amount that
you will have time to apply
during the ‘pot life’.
sure you have all the
components, tools, etc
ready before mixing.
the end of the ‘pot
life’ the mixture
will begin to get warm and can become dangerously hot. Be careful
especially if using plastic mixing pots.
the epoxy will
quickly the actual ‘curing’ can take days before full strength
epoxies are best used
when temperatures are
between 15C (60F)and 25C (80F) and when humidity is low.An increase in
temperatures will reduce the working time but will thin it making it
I am perfectly aware that the majority of Wooden Boat aficionados are sensible folk. However, I need to point out that I am an amateur wooden boat enthusiast simply writing in order to try to help other amateur wooden boat enthusiasts. And while I take every care to ensure that the information in DIY Wood Boat.com is correct, anyone acting on the information on this website does so at their own risk.