coating material MIL-M-3171 until you obtain a
greenish-brown or brass-colored yellow color. For a
proper conversion coating, keep the surface wet with
the specified solution until you obtain the desired
color. Rinse with fresh water. Remove any excess
conversion coating solution that collects into pools
within the aircraft.
Some magnesium parts in later model aircraft
were originally protected by a proprietary (held under
patent) electrolytic process. One process is identified
by the brown to mottled gray appearance of the
unpainted surface. Another process will appear as a
green to grayish-green color. These coatings are
thicker than those applied by the immersion or brush
method, such as MIL-M-3171. The electrolytic finish
cannot be restored in the field. Therefore, when failure
of the coating occurs, you should remove corrosion
and touch up the bare magnesium with MIL-M-3171
chemical treatment solution. You should minimize
removal of the electrolytic coatings, as they afford
greater protection than the replacement coatings.
What is the purpose for chemically treating a
surface for painting?
When failure of the coating occurs, you should
remove corrosion and touch up the bare
magnesium with what chemical treatment
AIRCRAFT PAINTING AND
LEARNING OBJECTIVE: Identify the
materials used and procedures for painting
The amount of paint touch-up done at
organizational- and intermediate-level maintenance
varies widely. The amount depends upon the activity
involved, the availability of facilities, and the area of
The primary objective of any paint finish is the
protection of the exposed surface against decay. There
are secondary reasons for particular paint schemes.
Glare is reduced by nonspecular (not mirrorlike)
coatings. White or light-colored, high-gloss finishes
reduce heat absorption. Camouflage, high visibility, or
special identification marking requirements are met by
various paint schemes. REPAINTING SHOULD
NOT BE DONE FOR APPEARANCE SAKE ONLY.
A faded or stained but well-bonded paint finish is
better than a fresh touch-up treatment applied over
dirt, corrosion products, or other contaminants.
Complete refinishing (particularly under field
conditions) should be restricted to those areas where
existing paint finishes have degraded until they fail to
perform their protective function. However, the
organizational and intermediate levels of maintenance
should evaluate maintenance and repair of paint
finishes. This should be done at the time of aircraft
receipt and through constant surveillance and
maintenance of finishes during an aircrafts service
tour. Maintenance also should make final
recommendations for refinishing an aircraft when the
aircraft is scheduled for standard depot-level
General safety precautions should be followed
when you paint and when you use special types of
paints. These precautions include the following:
No eating, drinking, or smoking is allowed in
areas where paint or solvent is being used.
Prolonged breathing of vapors from organic
solvent is dangerous. Prolonged skin contact with
organic solvents or materials containing organic
solvents can have a toxic effect on the affected skin
Paint removal operations at the organizational and
intermediate levels of maintenance are usually
confined to small areas, or possibly a whole panel. In
all cases, the procedures outlined in the MIM that
applies should be observed. General stripping
procedures are contained in NAVAIR 01-1A-509.
All paint removers are toxic and caustic; therefore,
both personnel and material safety precautions must
be observed in their use. Personnel should wear eye
protection, gloves, and a rubber apron.
Paint remover, specification MIL-R-81294, is an
epoxy paint remover for use in the field. This remover
will strip acrylic and epoxy finishes. Acrylic windows,
plastic surfaces, and rubber products are damaged by
this material. This material should not be stocked in
large quantities as it ages rapidly, degrading the results
of stripping action. This paint remover must NOT be
used to remove paint from composite materials.
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