Piper CHEROKEE WARRIOR PA-28-151 1995 Maintenance Manual page 63

PIPER CHEROKEE WARRIOR SERVICE MANUAL
There are several methods for removing corrosion; chemical treatment; hand sanding with abrasive paper
or metal wool; and, mechanical sanding or buffing with abrasive mats or grinding wheels. The method selected
depends on the type and extent of the corrosion.
Depressions resulting from rework must be faired into the surrounding surface.
The depth of materials removed should not exceed the safe limits.
Reprotecting the surface after corrosion removal is very important. It should be done as soon as the repair
work is finished. The surface should be protected in the same manner as the original surface was protected
unless the manufacturer recommends some other procedure or protective coating.
TYPE OF MATERIAL
Steel
Aluminum
Magnesium (highly susceptible
to corrosion)
Cadmium (plating)
Chromium (plating)
(1) Red rust generally shows on bolts, nuts, and other aircraft hardware. Rust in these areas is generally not
dangerous. It shows a need for maintenance and the possibility of corrosive attack in more critical areas.
Any surface corrosion on highly stressed steel parts is potentially dangerous. A careful removal of corro-
sion using mild abrasives (rouge or fine grit aluminum oxide paper) is necessary. Do not overheat metal when
removing corrosion.
(2) For abrasion, do not use dissimilar material (for example steel wool on aluminum). Remove only material
required to clean affected area.
Revised: February 28, 1995
TABLE II-V. TYPES OF METAL CORROSION
TYPE OF CORROSION
Rust (1)
White to grey powdery material
White powdery snow-like
mounds and white spots
White to brown to black mott
ling of surface (plating is
still protecting until iron
appears)
May pit in chloride environment
1C15
Island Enterprises
REMEDY (2)
Complete removal of corrosion
by mechanical means
Mechanical polishing or
brushing with material softer
than aluminum
Mechanical polishing or
brushing for a smooth finish
Mechanical removal of
corrosion is limited to metal
surfaces from which cadmium
has been depleted
Polishing and buffing
HANDLING AND SERVICING