PREVOST H3-41 Maintenance Manual page 704

SECTION 18b: X3 SERIES BODY
undercoating from damaged area, and wipe
clean with solvent.
Preheat the area to be repaired using heat
lamps. Mix desired quantities of resin and
hardener according
instructions. Add powdered fiberglass strand into
mixture to thicken it into a putty state.
NOTE
If repair is made on a vertical surface, adding
powdered filler material to mixture will reduce
tendency of hot resin to flow or run.
Apply the material with a putty knife or similar
object, building material up to the desired
contour. For deep filling and on vertical surfaces,
several layers of material may be used.
A hacksaw blade, held flat to adjacent contour
and then moved in a sawing action across the
repair when the resin is in a gel state, will
remove excess resin from repair. Finish repair
with the same procedure as when using
fiberglass cloth.
7.3 TYPICAL FIBERGLASS REPAIR
PROCEDURE
Remove all loose particles or damaged material
using a power sander or rasp. Clean area,
overlapping hole approximately 1" to 1-½" (25-40
mm) all around. Remove all dirt, grease and
paint from area to ensure good bonding surface.
Feather the cleaned area all around (Figure 5).
FIGURE 5: FIBERGLASS REPAIR
Cut a piece of fiberglass mat slightly larger than
area being repaired. Impregnate mat with
general purpose polyester
normally. Use a clean paint brush to apply the
polyester resin. Apply impregnated mat over hole
and press onto surface with brush to obtain good
adherence. Another coat of general purpose
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PA1621 Maintenance Manual All Series | Revised Sept 2019
to manufacturer's
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resin catalyzed
polyester resin can be applied at this time
(Figure 6).
FIGURE 6: FIBERGLASS REPAIR
NOTE
Remove all air between surfaces being joined.
Allow area to harden and sand surface to
remove any wax.
Apply another mat, followed by a cloth patch,
and another mat. All layers must be thoroughly
impregnated with polyester resin, brushed well
and free of air. Apply more layers of mat and
cloth as required until the desired strength and
thickness is obtained, minimum two 1-½ oz
(43 g) mats and one 9 oz (255 g) cloth (Figure
7).
FIGURE 7: FIBERGLASS REPAIR
Allow area to harden and contour the area with
coarse sandpaper #100 (Figure 8).
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