PREVOST X3-45 Multiplex, Руководство по обслуживанию

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Section 18: BODY
PA1562
12
4 COMMON FIBERGLASS REPAIR
PROCEDURE
All repairs to fiberglass parts consist of filling the
damaged area with fiberglass cloth and resin or
strand fiberglass and resin. The repair is allowed
to harden, and then finishing operations may be
performed. Use of the various materials is
determined by the type of repair to be made.
Large holes, torn sections and separate joints
require the adhesive qualities of the resin and
the reinforcing qualities of the fiberglass. Small
dents, scratches or pits can be repaired using
resin and strand fiberglass and filler mixed into
paste. Instructions for either mix are explained
under their respective headings in this section.
For best results when making repairs,
temperature should be between 70 and 75
o
F
(21-24
o
C). Some people experience a skin
reaction to resins. In such cases, wipe resin off
with denatured alcohol or a good thinner. Use of
protective hand cream is recommended.
WARNING
Always wear a respirator and goggles when
grinding or sanding.
Extreme care must be taken if the sander is
electrically operated, as dust from some resins
is combustible when subjected to sparks or
open flames. The proper tool for sanding resin is
a low speed, air driven disc sander with a water
attachment or a dry sander having a vacuum
bag. Either will eliminate flying glass and resin
dust.
The following additional tools and materials will
assist in making repairs: hacksaw blade,
assorted files, emery paper or cloth (150 or
finer), scissors or tin snips, wax paper or
cellophane sheets, a 3" (75 mm) paint roller,
paint brush, putty knife, acetone and one or
more heat lamps.
4.1 REPAIR USING FIBERGLASS CLOTH
Where necessary, sand paint away around
damaged area and scrape away undercoating, if
any, and wipe clean with solvent. Grind or file
the damaged area to form a "V" at the broken or
cracked portion. Sides of "V" should have a
shallow pitch for maximum bonding area.
NOTE
Roughening the surface improves adhesion of
resin.
If part is warped from original shape, use clam-
ping equipment to straighten the surface.
Preheat area to be repaired with one or two heat
lamps placed 18 to 24 inches (450-610 mm)
from repair.
CAUTION
Temperature should not exceed 140
o
F
(60
o
C) during 30 minutes in order to avoid
distortion.
Cut fiberglass cloth with scissors or tin snips, 1
to 3 inches (25-75 mm) larger than area to be
repaired. Build area to desired height.
Mix resin and hardener following instructions on
their containers. Saturate layers of fiberglass
with mixture and place laminates over damaged
area. Smooth out wrinkles and make sure
general contour of area is maintained. Bubbles
and wrinkles can be eliminated with a roller.
CAUTION
The pot life of the mix is approximately 15
minutes. Any accidental contamination to the
skin, clothing, tools, etc. must be removed
within this period. Use acetone to remove
uncured resin.
Heat resin material again by placing heat lamps
18 to 24 inches (450-610 mm) from repaired
area. Allow 12 to 15 minutes for repair to cure.
After repair is cured, grind, file or sand to
contour. Files other than body files may be more
suitable. Featheredge and finish sanding.
If small pits or irregularities appear after making
repair, correct by using a liberal amount of
chopped strand or filler mixed with resin to form
a paste. Refer to heading
"Repair using
Fiberglass Paste" in this section.
4.2 REPAIR USING FIBERGLASS PASTE
Fiberglass paste is used for repairing small
dents, scratches, and pits. Paste is made by
mixing resin, hardener and fiberglass strand or
filler to the consistency of putty. Where it may be
necessary, sand paint away around damaged
area. On underside of coach, scrape away
undercoating from damaged area, and wipe
clean with solvent.