Section 12 HULL/BODY
Subsection 02 (ADJUSTMENT AND REPAIR)
12-02-18 SMR2000-071_12_02A.FM
Test spray the gelcoat mixture on paper to verify
its consistency and pattern. You may have to apply
5 or 6 coats to cover the area properly. Overlap
each coat further than the last, leaving at least 30
seconds between passes. Avoid trying to coat the
surface with only a few heavy coats, this will not
allow the gelcoat to dry properly.
Apply a coat of polyvinyl alcohol to seal off the air
and protect the gelcoat surface from dust. PVA
speeds up the curing process because gelcoat will
not cure properly when exposed to air.
SANDING
Wash the polyvinyl alcohol off with water. De-
pending on the size of the area repaired, you can
either block sand as per previous procedure or you
may use an air sander. Sand the surface down with
progressively finer grits of sandpaper until the de-
sired finish is achieved.
BUFFING AND WAXING
Buff the surface using a heavy duty polisher with
a buffing pad. Make sure the pad is free of dirt or
you may damage the gelcoat. Carefully begin buff-
ing with a white medium compound. Finish off us-
ing a fine compound. While buffing, pay close at-
tention to avoid overheating the surface.
Compound Fractures
Possible causes:
– Thickness of fiberglass laminate.
– Direct result of impact.
Compound fractures are those that have gone
past the gelcoated surface and in through the lay-
ers of fiberglass laminate. Two types of repairs
have to be performed. The first is to restore the
structural integrity of the damaged area. Fracture
types can vary from a simple crack to a large hole.
Usually, fiberglass reinforcement becomes neces-
sary, especially if the fracture can be attributed to
weakness. The final part of the repair is the
gelcoating, which cannot be done until the interior
and exterior laminate surfaces have been repaired.
Outside
Remove the damaged gelcoat and fiberglass with
a 24-grit disk using a power sander. Grind outward
at least 2 inches from the fracture to allow the
patch to bond to strong material. Cut enough piec-
es of fiberglass mat necessary to build up the area.
The pieces should be cut so they overlap each oth-
er by at least a half inch. For a smoother finish, the
last layer should be fiberglass cloth. If the fracture
is small enough all you may have to do is fill the
area with an epoxy filler.
Inside
For the interior repair, you can grind more. This will
allow for more fiberglass material which will
strengthen the area. If the fracture opening is too
large after surface preparation, you may need a
backing support to cover the opening. Cut alternat-
ing pieces of fiberglass mat and cloth in overlap-
ping sizes.
PATCHING THE REPAIR AREA
Outside
The outside should be done first. Wipe clean the
area with acetone on a cloth, then mask off area.
For a small crack use an epoxy filler in the same
way you would use Bombardier’s gelcoat repair
putty. When laying up a larger area you will use
mat, cloth and fiberglass resin and hardener. Use
a clean container to mix the resin, mix only what
you will need. Follow the recommended catalyst
ratio.
Using a clean paintbrush, brush the mixed resin on
the surface. Place the smallest piece of mat over
the fracture and then wet out the mat. Follow with
the remaining pieces of mat and final layer of
cloth. While wetting the pieces make sure you
work the air bubbles out and saturate all the pieces
evenly. Try to work quickly, you may only have 15
or 20 minutes. You may clean the brush with ace-
tone.
Wait until the repair has hardened before moving
on to the interior repair. If the size of the opening
is too large for the pieces to maintain the proper
shape, you will have to use a backing support. It is
a shaped piece of cardboard that fits flush to the
interior surface and has a plastic layer on the repair
side. It is held in place by tape or a support.
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