PRACTICAL BOATER
DO-IT-YOURSELF
PROJECTS TO IMPROVE YOUR BOAT BY LENNY RUDOW
HOw TO rePair crazing
Crazing in gelcoat, also known as spider cracks or stress cracks,
plagues countless boaters. Here’s how to fix the problem
Crazing iS an incredibly cOmmOn iSSUe on modern fiberglass boats, and although it usually starts off as a matter of cosmetics, in severe cases these surface cracks can grow, deepen, and eventually threaten your boat’s structural integrity. They usually form in areas where the fiberglass is under unusual stress (such as rail stanchion
and anchor pulpit attachment points, transom corners, and around hardware), or
in areas where significant impacts have
occurred, such as rub rail collision zones or
where a heavy object was dropped. You’ll
want to fix them quickly because they can
grow worse over time — but don’t worry, it
isn’t a hard job. With a little bit of know-how
and a few basic tools, you can tackle this task
on your own.
BEFORE YOU BEGIN
If the cracks on your boat were caused by
impacts, such as around rub rails or where a
heavy object was dropped, move on to Step
1. If, however, the spider cracks appeared at
an attachment point or in a high-stress area,
there’s a good chance they’ll simply return
after you fix them. In this case, before you
attack a single crack, you need to reinforce
the area. Adding (or up-sizing) backing
plates to attachment points and bracing
to high-stress areas is probably going to
be necessary. There’s some chance you’ll
discover the need for significant repair
work, such as a broken bulkhead, which
is best left to a pro. But in most cases, DIY
reinforcements should do the trick. How
will you know if the reinforcing job you’ve
done is sufficient? There’s really no way to
be sure, until you repair the crazing and see
if the cracks come back.
STEP 1 PREP THE AREA
FOR CRACK REMOVAL
Before you can start to fix crazing, clear the
area of any obstructions and remove all hardware that covers or obscures any part of the
cracks. Then, get busy cleaning. Thoroughly
wash and dry the area, and remove all obvious surface contaminants with a rag dipped
in a strong solvent like acetone.
STEP 2 SAND THE SURFACE
A surface area at least a quarter-of-an-inch
wide (including the crack itself) will need
Grind out the cracked
surfaces with a dremel
Apply gelcoat with a putty
knife or plastic spreader.
When gelcoat is dry, sand
the surface flush with the
surrounding surface.
TecH SUPPOrT
Degree Of Difficulty
TOOLS:
dremel
cone- or bullet-shaped
silicon carbide or
tungsten carbide
dremel bit
Sanding block
Plastic resin spreader
or putty knife
MATERIALS:
Solvent wash (such as acetone or interlux
202) $19
rags $3
medium 60- to 80-grit sandpaper $2
Fine 220- to 240- grit sandpaper $2
Super-fine 400-grit sandpaper $2
Ultra-fine 600- to 800- grit sandpaper $2
gelcoat paste and hardener $30
coloring agent (as necessary) $10
assorted mixing sticks and containers $3
Plastic wrap $0
PROJECT COST
$73 (based on west marine pricing)
APPROXIMATE YARD TIME/COST:
The time required for this job will obviously
vary quite a bit depending on the number
of cracks and how widespread they are, but
should take no more than three hours per
square foot of repair area. Fiberglass repair
costs between $60 and $110 per hour in a
yard, so you’ll save $180 to $330 by doing the
job yourself.
