MCi Crusader II 1989 Maintenance Manual page 90

Date
1-1-89
Page . ___
3-_11 _ _
MC-9 MAINTENANCE MANUAL
CAUTION: Some people e:itperlence a skin
reaction to resins. It this happens, wipe off
skin with denatured alcohol or clean
thinner. There are several protective hand
creams available and their use Is recom-
mended.
If any disc grinding or sanding is to be done in an enclosed
area, a respirator should be used and goggles should be worn.
Extreme care must be taken if the sander is electrically
operated as dust of some resins is combustible when subjected
to sparks or open flame. 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 attachment Either wifl elimi-
nate fiberglass and resin dust
FIBERGLASS CLOTH PROCEDURE.
1. Remove all loose particles or damaged material using a
power sander or rasp and where necessary sand paint away.
On underside of coach scrape undercoating off and wipe clean
with solvent Remove all dirt, grease and paint to 1 ½" around
damaged area and feather the cleaned area all around.
2. Grind or file the damaged area to form a "V" at the broken
or cracked portion. Sides of the "V" should have a shallow pitch
for maximum bonding area.
NOTE: Roughening the surface improves
adhesion of resin.
3. If paneling is warped, use C clamps and improved clamp
plates to align surfaces. Preheat area to be repaired using one
or two heat lamps positioned 12 to 15 inches (305-381 mm) from
repair area.
CAUTION: 200°F (93°C) is the high limit
for this material. To go higher is to risk
material distortion or crystallizing.
4. Cut a piece of fiberglass one to three inches larger than
the area to be repaired and impregnate with general purpose
polyester resin catalyzed normally. Mix the desired quantity of
resin and hardener in proportions of
½
tablespoon hardener to
one quart resin. Do not use wax cups for mixing and prevent
contamination between resin and hardener cans. A thin mixture
can be thickened by adding powdered filler.
5. Use a clean paint brush to apply the resin placing the
impregnated mat over the hole and pressing onto the surface
with
the brush to obtain good adherence. Another coat of resin
may be applied at this time. Alternate layers of mat and cloth
saturating each layer of fiberglass as it is placed over the
damaged area. Smooth out the wrinkles while ensuring that the
general contour of the area is maintained. Bubbles and wrinkles
an be rolled out using a roller.
6. When the required strength . and thickness is obtained
{two 1
½
oz. [52.5 g] mats and one 9 oz. [25~ g] cloth), allow the
area to harden. Allow sufficient time for the patch to cool off
properly before proceeding.
NOTE: Be sure all air is removed from
between surfaces being joined.
CAUTION: Once the resin and hardener
have been mixed, the pot life (working
time) of the mix Is approximately 15 min-
utes. Any accidental contamination to the
skin, clothing, tools, etc., must be removed
within this period. Use acetone to remove
uncured resin.
7. Heat resin material again placing lamps 12 to 15 inches
(305-381 mm) from repaired area. Allow 12 to 15 minutes for
repair to cure.
8. After repair is cured, grind, file or sand to contour. Files
other than body files may be more suitable. Feather edge and
finish sanding.
9. After ro1Jgh sanding, small pits or irregularities may
appear in the finished surface. Repair following the instructions
under Fiberglass Paste Repairs. Smooth off the surface with
100 sandpaper and finish with 120 sandpaper. Reprime and
repaint according to approeriate painting instructions.
FIBERGLASS PASTE REPAIRS
A fiberglass paste is used for repairing small dents, scratches.
and pits. The paste is made by mixing resin, hardener and
fiberglass strand or filler to the consistency of putty.
1. Where necessary, sand paint away around damaged
· area. On underside of coach, scrape away undercoating from
damaged area and wipe clean with solvent
2. Preheat the area to be repaired using heat lamps. Mix
desired quantity of resin and hardener (refer to manufacturer's
instructions on container). Add powdered fiberglass strand into
mixture to thicken it into a putty state.
CAUTION: If repair 111 to be made on a vertl•
cal surface, adding of powdered filler mate-
rial to mixture will reduce tendency of hot
resin to flow or run.
3. Apply the material with a putty knife or similar object,
building material up to desired contour. For deep filling and on
vertical surfaces several layers of material may be needed.
4. A hacksaw blade held flat to adjacent contour and then
pulled, using sawing action across repair when the resin is in
the jell stage will remove excess resin from repair.
5. Finish repair in the same manner as when using fiberglass
cloth.
FIBERGLASS ROOF PANEL REPLACEMENT
Should replacement of a complete fiberglass roof panel
assembly be required, it is recommended that the panel be fitted
to the roof section and marked from the underside in the areas
where the root bows are located.
1. If the roof bow channels are bent or damaged, they should
be altered or replaced in order to match the contours of the