Overview: Cost, savings and repair strategy
Even the best boat captain has had a
docking turn into a scuff-and-chip event.
But you don't have to pay astronomical
marina fees to get your boat fixed. You can do it
yourself with advice from expert fiberglass repair
specialist Chris Hassis. He's fixed boo-boos on
fiberglass personal watercraft, snowmobiles and
pickup toppers, and even luxury yachts. You'll
need the right tools and materials—and lots of
patience. But he'll show you how to save a ton of
money and make your boat look like new. We were
astounded at this refurbished boat's rebirth.
The boat now looks every bit as good as it did in
Most hired-out repairs of any type
are roughly 50 percent labor and 50
percent materials. Not so with this
fix—hull repairs are all about labor.
The repairs on this boat would cost
roughly $3,000 at a shop. But the materials
only cost about $250 and the buffer
about $150! So roll up your sleeves. Your
repairs might not be perfect, but your
boat will look unbelievably better than
it did before. Just don't try to rush or
skimp on the materials. And know that
this job is much bigger than it looks.
All fiberglass boats have a thick
structural core of fiberglass strands
impregnated with polyester resin. But
the part you actually see is the gel coat.
That's the thin layer of pigmented resin
that gives the boat its sheen and color.
Most light scratches are in the gel coat
layer. They can be sanded out and the
area built back up with new gel coat.
But if they penetrate the core, they
need to be filled. You can tell that the
scratch is into the core if you see fiberglass
fibers (Photo 2).
No boat spiff-up is complete without
new license numbers, transom names
and pinstripes. Just do an online
search for “boat graphics” and you'll
find thousands of options to choose
from. Find stripes by searching for
“boat pinstripes.” Remove the old ones
by warming them with a heat gun
(Photo 1). But be careful—if you overheat
the surface, you can burn the gel
coat. If yours are painted on, sand them
off with 1,200-grit sandpaper.
Fix gouges: Prep
Grind out gouged areas with a
V-shaped grinder bit (Champion SF1; from heavydutystore.com
; Photo 2).
Sand out the light scratches, starting
with 80-grit and ending with 240-grit.
Fix gouges: Fill and smooth
To fix gouges and deep scratches, you'll
need “chop” (powdered fiberglass)
filler, gel coat and gel coat reducer. Jot
down your boat's model and serial
numbers and contact the manufacturer
to order gel coat (about $100 per qt.) to
match your boat's color. It may not be
an exact match, but it'll be a lot closer
than mixing colors from scratch. Then
order some gel coat reducer (Patch-Aid
is one brand; about $49 per qt. from minicraft.com or spectrumcolor.com) to
thin the mixture enough to go through
the spray gun. For gouge repair, you'll
mix chop filler (Chris uses Cab-O-Sil from
epoxy5050.com) with the gel coat to
create a thick paste. Then pick up
paper cups, stir sticks, acetone (for
cleanup) and rags. You'll also need a
disposable spray gun (Preval is one
brand; about $7 online or at paint and art supply
stores). To finish the job, you'll
need a professional-type buffer. The
variable-speed feature is important,
and so is the high power of a professional
buffer. So don't skimp on one or
think you can get by with a $29 wax
polisher. Use a wool buffing pad (such
as a Dewalt DW4988 pad, available through our affiliation with amazon.com or westmarine.com), and
buffing compound (3M Imperial
Compound and Finishing Material, which is what Chris uses, available through our affiliation with amazon.com or westmarine.com).
Mixing gel coat is a messy and stinky
process—so wear chemical-resistant
gloves, safety goggles and a respirator.
Start with a small amount of gel coat
and stir in the chop and hardener to
make a putty that's the consistency of
peanut butter (Photo 3). Once you add
the hardener, you've only got a 10- to
20-minute “open” time, so mix small
batches and work on one gouge at a
time. Thorough mixing is critical to
proper curing. Spend a full
minute stirring. If you don't,
you'll end up with patches of
sticky resin that can take
days to harden.
Overfill gouges so the
filler mounds slightly.
You'll sand it flush after it
cures. Curing can take one
to two hours—depending
on humidity levels. So test
it by touch. If it's sticky, it's
not fully cured. Once it's
fully hardened, sand it
with 80-grit sandpaper
Color-Matching Gel Coats
Sometimes you can't get your hands
on factory gel coat (your boat is too
old or the manufacturer is out of
business). Then you have two
options. You can order an off-the-shelf
color that's close to yours and
decide that “close enough is good
enough.” The other option is to custom
mix, but be aware that this is no
easy task. Buy a color chip chart for
off-the-shelf colors (from a local
marine supplier, or get the No.
01900 color chart from rayplex.com
for about $12). Mix your own color with
a kit (No. 33114; about $35) from
Fix gouges: Apply the finish
Now you're ready to mix a fresh
batch of gel coat (without the chop)
and spray the scratched and patched
areas (Photos 6 and 7). Chris recommends
using a disposable spray gun
and paper cups. Unthinned gel coat
won't go through the sprayer. Add the
recommended amount of reducer
(read label directions) and hardener
and mix the ingredients. Spray the
patched areas with short bursts.
Spraying gel coat isn't like spraying
paint. It splatters on and has to be
sanded and buffed to get to a smooth
gloss. So don't be disappointed that
the finish isn't paint-like right away.
Back to Top
Final-sand, buff and wax
Wait for the gel coat
to cure. Sand the
repairs with 600-grit
and then 800-grit
sandpaper. For the
perfect finish, sand
with 1,200-grit wet/
dry paper then buff
(Photo 8). Apply buffing
directly to the pad.
Work on a 2 x 2-ft.
area and use light to medium pressure
at a fairly low speed. Reduce pressure
as the compound starts to dry. Wipe
off the haze as you go. Apply the
graphics and then wax.
Order of Events
Wash and rinse the boat. That
will show you all the dings that
need fixing. Mark them with
masking tape so you won't
If you're replacing pinstripes,
license decals or other graphics,
remove them next.
Fill any deep gouges and spend
your time sanding out scratches
while the filler sets up.
Apply gel coat to the filled
gouges and finish to the scratches
and then final-sand the filled
Buff all the repaired areas and
then the rest of the boat.
Apply any graphics to finish up.