Piper SARATOGA PA-32-301 Maintenance Manual page 418

PIPER AIRCRAFT
PA-32-301/301T
MAINTENANCE MANUAL
H. For repairs in areas involving little or no shear stress, the hot melt adhesives. polvamids which
are supplied in stick form may be used. This type of repair has a low cohesive strength factor.
1. For repairs in areas involving small holes, indentations or cracks in the material where high
stress is apparent or thin walled sections are used, the welding method is suggested.
J. This welding method requires a hot air gun and ABS rods. To weld. the gun should be held to
direct the flow of hot air into the fusion (repair) zone. heating the damaged area and rod simultaneously. The
gun should be moved continuously in a fanning motion to prevent discoloration of the material. Pressure must
be maintained on the rod to insure good adhesion. (Refer to Figure 51-5.)
K. After the repair is completed, sanding is allowed to obtain a surface finish of acceptable
appearance.
4. Cracks: (Refer to Figure 51-6.)
A. Before repairing a crack in the thermoplastic part. first determine what caused the crack and
alleviate that condition to prevent it recurring after the repair is made.
B. Drill small stop holes at each end of the crack.
C. If possible. a double plate should be bonded to the reverse side of the crack to provide extra
strength to the part.
D. The crack should be "V" grooved and filled with repair material, such as solvent cement, hot
melt adhesive. epoxy patching compound or hot air welded, whichever is preferred.
E. After the repair has cured, it may be sanded to match the surrounding finish.
5. Repairing Major Damage: (Larger than I inch in diameter.) (Refer to Figure 51-7.)
A. If possible a patch should be made of the same material and cut slightly larger than the section
being repaired.
B. When appearances are important, large holes, cracks, tears. etc., should be repaired by cutting
out the damaged area and replacing it with a piece of similar material.
C. When cutting away the damaged area. undercut the perimeterand maintain a smooth edge. The
patch and or plug should also have a smooth edge to insure a good fit.
D. Coat the patch with solvent adhesive and firmly attach it over the damaged area.
E. Let the patch dry for approximately one hour before any additional work is performed.
F. The hole. etc.. is then filled with the repair material. A slight overfilling of the repair material is
suggested to allow for sanding and finishingafterthe repair has cured. If patching compound is used the repair
should be made in layers. not exceeding a 1 2 inch in thickness at a time, thus allowing the compound to cure
and insuring a good solid buildup of successive layers as required.
6. Stress Lines: (Refer to Figure 51-8.)
A. Stress lines produce a whitened appearance in a localized area and generally emanate from the
severe bending or impacting of the material. (Refer to Figure 51-9.)
B. To restore the material to its original condition and color, use a hot air gun or similar heating
device and carefully apply heat to the affected area. Do not overheat the material.
7. Painting the Repair:
A. An important factor in obtaining a quality paint finish is the proper preparation of the repair
and surrounding area before applying any paint.
B. It is recommended that parts be cleaned prior to painting with a commercial cleaner or a solution
made from one-fourth cup of detergent mixed with one gallon of water.
C. The paint used for coating thermoplastic can be either lacquers or enamels depending on which
is preferred by the repair facility or customer. (See NOTE.)
-NOTE
-
It is extremely important that solvent formulations be considered
when selecting a paint, because not all lacquers or enamels can be
used satisfactorily on thermoplastics. Some solvents used in the
paints can significantly affect and degrade the plastic properties.
51-10-04
Page 51-11
2G5
Issued:
January
2, 1980
2G5