Cessna 172 Skyhawk SERIES, Maintenance Manual

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CESSNA AIRCRAFT COMPANY
SINGLE ENGINE
STRUCTURAL REPAIR MANUAL
(2) Make plug patch slightly thicker than the material being repaired, and similarly bevel the edges.
(3) Install plug patch as illustrated in Figure 801.
(4) Heat plug patch until it is soft, press into the hole without plastic solvent adhesive, and allow to
cool to make a perfect
fi t.
(5) Remove plug patch, coat surfaces to be bonded with plastic solvent (acrylic chips dissolved in
methylene chloride), and insert plug patch in the hole.
(6) Maintain a fi rm, light pressure until the plastic solvent adhesive has set.
(7) Sand or fi le edges level with surface; buff and polish. Do not attempt hand polishing until surface
is clean. A soft, open-type cotton wheel is suggested.
NOTE: Acrylic and cellulose plastics are thermoplastic. Friction created by buf fi ng or
polishing for too long a time in one spot can generate suf fi cient heat to soften the
surface. This will produce visual distortion and is to be guarded against.
6. Minor Scratches
A. The following procedure should be used when repairing minor scratches.
(1)
Remove minor scratches by vigorously rubbing the affected area by hand, using a soft, clean
cloth dampened with Novus 2 plastic polish, and
fi nish by polishing with Novus 1. Remove polish
with a soft dry cloth.
NOTE: Plastics should not be rubbed with a dry cloth, since this is likely to cause scratches,
and also builds up an electrostatic charge which attracts dust particles to the surface.
If, after removing dirt and grease, no great amount of scratching is visible,
fi nish the
plastic with a good grade of commercial wax. Apply the wax in a thin, even coat, and
bring to a high polish by rubbing lightly with a soft cloth.
7. Cleaning Plastic
A. The following procedure is the recommended method for cleaning plastic windows.
(1)
Clean the plastic by washing with plenty of water and mild soap, using a clean, soft, grit free
cloth, sponge, or bare hands.
CAUTION: Do not use gasoline, alcohol, benzene, acetone, carbon tetrachloride,
fi re extinguisher or deicing fl uids, lacquer thinners, or window cleaning
sprays because they will soften the plastic and cause crazing.
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Page 804
© Cessna Aircraft Company
Jun 1/2005