Ask any ten boaters how they protect the exterior wood of their boat and you’ll get ten answers, sometimes at length. There is no question that the deep, lustrous look of twelve coats of gloss varnish on a cap rail epitomizes boating elegance. Living with that reality is a different story.
It used to be
traditional varnish or leaving the wood bare were the only choices and the “bare”
option only worked for teak. Modern chemistry has changed all that, providing a
bewildering number of choices in finishing that exterior wood. A casual look at
a boating supply web site shows 27 different types of varnish alone, not
counting the other types of marine wood finishes.
The areas that
will need finishes, aboard a boat, can be broken down into two different areas,
exterior and interior. Finishes have evolved to meet those areas needs in
varying degrees. Let’s look at some of those options and consider their
effectiveness and suitability for the look you want on the wood on your boat.
Varnishes
Varnishes have
been around the longest in protecting wood aboard a boat. The varnish protects
the wood from water, oil and grease and provides protection from the sun’s UV
rays. Most varnishes are composed of
varying degrees of five different ingredients:
·
Oils
·
Resins
·
Solvents
·
Dryers
·
Ultra-Violet
protection additives
As they say,
“the devil is in the detail”, and what differentiates these products is the
type and amount of each ingredient. For example, satin varnishes, designed for
use below decks, will have much less UV additive than an exterior gloss varnish
and more of a flattening agent for the satin look.
Each of the
components in a varnish contributes to the overall effectiveness and purpose of
the varnish. The oils, most commonly Tung oil in high quality varnish and Soya
in lower quality ones, allow the varnish to penetrate the wood fibers. The more
oil in a varnish the better it penetrates the wood.
Resins can be
organic, in traditional varnishes, or synthetic, used in formulations that are
more modern. The resin component makes a significant contribution to the water
resistance of a varnish. The resin to oil ratio has a significant effect on the
drying times and durability of the final coating. Longer drying times allow a
more durable finish at the risk of defects in the finish from weather changes
(rain or dew) and insect and dust inclusion.
The solvents and
dryers provide for brush-ability and contribute to the final flexibility and
water resistance of the varnish. The UV additive, obviously, protects both the
wood and the finish from the damaging UV rays from the sun.
The choice of a
varnish is a complex compromise. The harder the varnish, the more durable the
finish in terms of abrasion resistance and water damage. However, harder
finishes tend to become brittle and crack with the expansion and contraction of
the wood than a softer finish. Your choice of varnish will change based on
location. A varnish that holds up well in Maine
won’t be the best for use in
Varnish is also
more difficult to apply than some other finish choices. A proper finish is
built up out of multiple coats, as many as twelve or more, applied at the
proper interval and after the proper surface preparation. No small task on a
boat with extensive wood to varnish.
Probably the
most widely used non-varnish coating is Sikkens Cetol. These products use some
of the same components as varnishes (resins and UV additives, for example) but
differ in characteristics. They are thinner, penetrate the wood deeper and
provide a micro porous finish that allows the wood to breath.
Application is
easier than varnishing as the finish, being thinner, flows easily. Three to
four coats are recommended, with a yearly maintenance coat suggested. More
frequent re-coating will be necessary in harsher climates, i.e.
Treating wood
with oil is a time-honored tradition. Typically, the oils use is Tung oil.
Linseed oil can be used but it darkens much faster than Tung oil. The oil is
easily applied by wiping it on with an oil soaked rag. Multiple coats are
applied until the wood surface is saturated.
The oil
treatment enhances the look of the wood, providing a natural satin finish.
Unfortunately, that look doesn’t last long as the oils darken in sunlight. Many
manufacturers add UV additives, pigments and other compounds to extend the life
and looks of the oiled wood. Plan on applying multiple coats to start with plus
regular maintenance coats.
Modern chemistry
has provided boaters the choice of a catalyzed finishing system. These finishes
use a catalyst to cure the resin into a durable surface. AwlGrip Awl-Brite,
Bristol Finish, Honey Teak and Interlux Perfection Varnish all fall into this
category. These products are similar to two-part paints, without the pigment.
In addition to
the durability aspect, rapid application is also possible. Often the time to
recoat is only three hours or so. This allows multiple coats to be applied in
the same day, reducing the overall time required to achieve an excellent
finish. Most of these products provide a clear, unpigmented coating,
accentuating the natural wood look.
Inventive
boaters have concocted some of their own solutions to the finishing issue. One
of the more common and successful is using epoxy as a base for a final finish.
After the wood is sanded and prepped, epoxy is applied to the wood, usually
three coats. The epoxy provides a strong, stable base coating effectively
sealing and protecting the wood.
The problem with
epoxy is that it has no UV protection and will begin to discolor and breakdown
after being exposed to the sun’s UV rays. To solve this problem, several coats
of a high-UV varnish are applied over the epoxy, thus providing the necessary
UV protection.
One caveat: test
your varnish over the epoxy on a sample before applying it to your boat. Some
varnishes are incompatible with the epoxy substrate and will not cure hard.
Proper cleaning and preparation of the epoxy surface is also necessary. The
resulting process provides a strong stable finish requiring minimal maintenance
coats of varnish.
The harsh
tropical sun is death on a fine varnish finish. Rather than spend time trying
to maintain that classic deep varnish look on their bright work, some cruisers
have taken the heretical step of painting their bright work.
Several coats of
white paint are applied over a good varnish base. The paint protects both the
varnish and the wood. After returning to more moderate climes, the paint is
removed and the varnished bright work restored to its original look. Heretical
but practical.
Another
traditional approach to teak finishes is to simply do nothing. Teak left
exposed to the weather naturally ages to a light gray color that some
(especially those tired of varnishing) find attractive.
Regular cleaning
of the bare teak will restore most of the original color at the expense of some
of the teak itself. Scrubbing with stiff brushes is to be avoided as it wears
away the softer grain while leaving the harder grain, resulting in a rough,
ridged surface.
Many times teak
decks are left unfinished to provide a better, less slippery footing.
Eventually the wear and tear and maintenance of the teak will require replacing
the decking, not a pleasant (or inexpensive) experience.
Application
Techniques
One of the most
important finishing techniques is to choose the right finishing solutions.
While reading the manufacturers sales literature can be enlightening, it isn’t
the best way of picking a solution. Rather, walk the docks of your marina and
look at other boats with bright work finished to your liking. Strike up a
conversation with those folks and find out how they did it, what products they
used and how long it took. Get a consensus for what works in your area. Most
boaters are happy to brag about their boats and their projects.
There are multitudes
of books written about finishing bright work on boats, for whichever finish you
choose. Temper their recommendations with what you learn from your fellow
boaters. You need to strike a balance between degrees of difficulty and
durability. Even an hour spent finishing is one less hour on the water.
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Posted by: Thomp Bill | February 06, 2012 at 04:28 AM