Restoring the Shine to Fiberglass
by Don Casey
The outer surface of a fiberglass boat is normally a special resin called
gelcoat. Gelcoat has little structural value-the underlying laminates
of resin-saturated glass fabric provide that-but gelcoat protects the
hull and gives it its color and shine.
When the gelcoat was originally sprayed into the hull mold, it-like
any gel-took on the shape and texture of the mold surface. The ultra
high gloss most new boats exhibit is due entirely to the highly polished,
mirror-like surface of the mold used in the original construction of
the boat.
Time and exposure eventually erode the relatively soft surface of gelcoat,
leaving it dull and chalky. Fortunately, the gloss usually can be restored.
Cleaning
The first step in restoring the gloss to dull gelcoat is always a thorough
cleaning. Add a cup of detergent to a gallon of water-warm water is
better-and use a sponge to wash the surface with this solution. Be sure
to protect your hands with rubber gloves.
If mildew is present, add a cup of household bleach to your cleaning
solution. Difficult stains like fish blood and waterline scum may require
the direct application of a concentrated cleaner formulated for fiberglass.
Rinse the clean surface thoroughly and let it dry.
Degreasing
For dependable results from wax or polish, the gelcoat surface must
be completely free of oil and grease. Detergents often fail to fully
remove these contaminants from porous gelcoat. Wipe the entire surface
with a rag soaked in MEK (preferred) or acetone, turning the rag often
and replacing it when you run out of clean areas. Again, protect your
skin with thick rubber gloves.
Wax
Keeping gelcoat coated with wax-starting when the boat is new-is the
best way to prolong its life. Regularly waxed gelcoat can retain its
gloss for 15 years or more. The real purpose of a coat of wax is to
protect, but wax also has restorative properties if the gelcoat is not
too badly weathered.
Application instructions vary among brands, but in general you apply
the wax with a cloth or foam pad using a circular motion. Let the wax
dry to a haze, then buff away the excess with a soft cloth, such as
an old bath towel. The remaining wax fills microscopic pitting in the
gelcoat and provides a new, smooth, reflective surface.
Polishing
Polish is not a coating, but rather an abrasive-like extremely fine
sandpaper. Polishing removes the pitted surface rather than coating
it. Use a soft cloth to apply polish to a small area at a time, rubbing
with a circular motion until the surface becomes glassy. After polishing,
you should apply a coat of wax to protect the surface and improve the
gloss. Some polish products include wax in their formulations.
Using
Rubbing Compound
If the gelcoat is weathered so badly that polish fails to restore its
shine, you will need the stronger abrasives rubbing compound contains.
Wax on the surface can cause the compound to cut unevenly, so first
remove all wax by "sweeping" the surface in one direction-not back and
forth-with rags saturated with dewax solvent or toluene.
Select a rubbing compound formulated for fiberglass and use it exactly
like polish, rubbing it with a circular motion until the surface turns
glassy. The gelcoat on your boat is about 10 times as thick as the paint
on your car, so compound shouldn't cut all the way through it as long
as you are careful not to rub in one place too long. If the gelcoat
starts to look transparent, stop.
After the surface has been compounded, polish it, then coat it with
wax and buff it. Providing the gelcoat has an adequate thickness-the
boat might have been compounded previously-this process will restore
the shine to fiberglass in almost any condition.
Do
You Need an Electric Buffer?
You can wax, polish, and compound by hand, but on anything but the smallest
boat, your arm is going to get very tired. An electric buffer takes
much of the work out of keeping a boat shining and is less expensive-and
less painful-than elbow replacement.
Electric buffers operate at relatively slow speeds, so don't try to
"make do" with a polishing bonnet fitted to a disk sander or a sanding
pad chucked into a drill. You will either ruin the surface or ruin the
tool. A buffer with an orbital motion will leave fewer swirl marks.
Restorer
In recent years a number of products have come on the market that claim
to restore the surface of the gelcoat. Restorer formulations renew the
gloss in essentially the same way as wax-by providing a new smooth surface-but
without the need for buffing. Results can be dramatic, but because restorers
are a plastic (acrylic) coating-similar to urethane varnish-they can
wear off, flake off, and occasionally discolor. Restorer kits typically
include a prep wash and sometimes a polish in addition to the restorer.
A specialized stripper-for removing old sealer-is also necessary.
There are variations in the recommended application, but in general
it is the same as already described-clean, polish, and coat. The acrylic
sealer is usually water-thin, so applying it to the hull is much easier
than, say, pastewax. And it dries to hard film, so no buffing is needed.
However, you do have to apply several coats-five is typical-to get a
good shine. If the product you have selected doesn't include an applicator,
use a sponge or a soft cloth to wipe the sealer onto the gelcoat. Drying
times are short, so subsequent coats can generally be applied almost
immediately.
A
multicoat application can restore the shine to weathered gelcoat for
up to a year, but when it is time to renew it, you will need to remove
the old sealer using the special stripper supplied in the kit (or available
separately). Apply five fresh coats of sealer and your boat should shine
for another year.
| 
