FAA Advisory Circular 43.13-1B
Acceptable Methods, Techniques, and Practices
Aircraft Inspection and Repair
AC 43.13-1B | 6. Corrosion, Inspection, and Protection | 3. Corrosion Protection Measures for Basic Materials | 6-41. Dope Proofing
AC 43.13-1B
9/8/98
brass, copper, or steel. This treatment cannot
be used with parts containing aluminum inserts
or fasteners because the high alkalinity of the
bath attacks the aluminum.
6-40. ORGANIC COATINGS. Zinc chro
mate primer, enamels, chlorinated rubber com
pounds, etc., are organic coatings commonly
used to protect metals.
6-36. GALVANIC ANODIZING TREAT-
MENT. An electrolytic process that provides
a paint base and corrosion-preventive film on
magnesium alloys containing manganese.
6-37. CLADDING. Aluminum alloys which
are susceptible to corrosion are frequently clad
with pure aluminum. Slight pits, scratches, or
other defects through the cladding material
must be avoided, since the aluminum alloy
core will corrode rapidly.
6-38. METAL SPRAYING. Metal is melted
and sprayed on the surface to be protected.
The surface must be properly prepared and
thoroughly cleaned to prevent peeling of the
sprayed coat.
6-39. SHOT-PEENING. Shot-peening and
other treatments, by which the surface can be
placed in compression, are effective in pre
venting stress corrosion.
6-41. DOPE PROOFING. When doped
fabrics are applied over an organic finished
metal structure, the dope will have a tendency
to loosen the finish on the metal. For this rea
son, organic coatings on the metal are usually
covered with a dope-proof paint, with metal
foil, or with cellulose tape to prevent the dope
from soaking through.
6-42. TUBE INTERIORS. Protect the inte
riors of structural steel and aluminum tubing
against corrosion. A small amount of water
entrapped in a tube can corrode entirely
through the tube thickness in a short period.
Coat the tube interior by flushing with hot lin
seed oil, paralketone, or other approved corro
sion inhibitor. The flushing liquid is usually
introduced through small holes drilled in the
tubing. Allow the flushing liquid to drain and
plug the holes with a screw or by other means
to prevent entry of moisture. Air and water
tight sealing of the tubing will also give ade
quate protection against corrosion if the tubing
is internally dry before being sealed.
6-43.6-49. [RESERVED.]
Page 6-12
Par 6-35