Section 12
HULL / BODY
Sub-Section 01
(ADJUSTMENT AND REPAIR)
12-01-15
WARNING : Protect skin, wear gloves
when in contact with resin, hardeners and
gelcoat. A barrier skin cream may also be used.
Do not expose area to open flame or lit ciga-
rette. Some of the materials are flammable.
Protect eyes, wear safety glasses when grind-
ing, sanding or spraying. Use a dust mask
when sanding or grinding. When spraying
wear a respirator or paint mask. Always read
warning labels on products.
Air Bubbles
Possible Cause :
– Air pocket trapped between layers of laminate
and gelcoat.
PREPARATION OF SURFACE
Remove all of the damaged gelcoat surrounding
the air bubble with a putty knife or preferably a
carbide grinding tip. Make sure all loose and weak
areas are completely removed. Sand a small area
of the gelcoat surface with 220-grit sandpaper. If
needed, sand the cavity itself. These areas must
have a rough surface to allow the gelcoat putty to
bond properly.
FILLING THE CAVITY
The prepared surface must be cleaned with ace-
tone on a cloth. Use the Bombardier gelcoat repair
kit (P / N 295 500 100). Follow the mixing instruc-
tions in the kit when preparing the gelcoat putty.
Carefully mix the required amount while making
sure there are no air bubbles in the mixture. With
a putty knife fill the repair area and cover with
plastic film. Curing time may depend on tempera-
ture, amount of putty and percentage of catalyst.
After 2 hours, press lightly on the surface with fin-
gers to test the hardness. When the area be-
comes hard, remove the plastic film.
SANDING
Begin block sanding the patch with 320-grit sand-
paper until you come close to the original surface.
Remove dust with a water soaked cloth and con-
tinue sanding with a 400-grit wet paper. Finish
wet sanding with a 600-grit to remove deeper
scratches. If needed you can wet sand with finer
grit paper such as 1000-grit.
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
buffing with a white medium compound (RM
856). Finish off using a fine compound (RM 852).
While buffing, pay close attention to avoid over-
heating the surface.
Blisters
Possible Causes :
– Insert catalyst.
– Improper catalyst / gelcoat ratio.
A blister is a visible bump on the watercraft sur-
face that may not necessarily come right through
the gelcoat layer. In the case of only a few blis-
ters, follow the same repair procedure as for air
bubbles. If they are numerous and in close con-
centration, spray liquid gelcoat to achieve proper
repair. This procedure is covered in the next prob-
lem.
Minor Gelcoat Fractures
Possible Causes :
– Flexing of fiberglass laminate.
– Gelcoat thickness.
– Direct result of impact.
In case of fractures which have not penetrated
past the gelcoat layer, the repair concerns the
gelcoat only. If flex cracking or impact are evident,
then additional reinforcement may be necessary.
This subject will be covered in the next problem.
PREPARING THE SURFACES
Small Fractures :
Open the cracks up with a sharp triangular can
opener or preferably a carbide tipped die grinder.
The V groove will provide a good bonding area for
the gelcoat. With 220-grit sandpaper, sand the
sides of the notched out areas.
Numerous Fractures :
Using a grinder with a 24-grit disk, remove the
gelcoat. Sand the area edge with 220-grit sandpa-
per.
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