Corrosion Prevention
General
Although corrosion protection measures and
painting processes in production have reached a
very high technical standard and will be
continuously developed further, in the long term
corrosion on a vehicle cannot be totally avoided.
Further demands are therefore made of the paint
specialist besides his knowledge of normal
repainting of vehicles which have been repaired
after an accident, in addition specialist knowledge
is required for assessing and rectifying damage
due to corrosion.
During repair painting, take care over the
maintenance and re-creation of the corrosion
protection applied in production, in view of the
long-term warranty on Ford vehicles. Only those
repair materials which are approved by Ford may
be used for body repair work and repair painting.
For detailed information on corrosion protection
measures during body repairs, please
refer to
Furthermore, information on corrosion protection
measures is repeated in individual chapters of the
paint manual.
In particular, pay attention that the layer
thicknesses specified in production are maintained.
The complete system of solid one-layer on
galvanized steel panels must equal at least 90 µm
and the total system of two-layer on galvanized
steel panels must equal at least 105 µm.
It is important that sealing operations, as far as
they are necessary, should be undertaken after
the application of the paint to specification, in order
to ensure the best corrosion protection. All
components which form hollow cavities such as
pillars, rails, side components etc. must be
provided with a coating of cavity protection wax.
Causes of corrosion
Corrosion of steel is an electrochemical process
during which the steel combines with oxygen. The
following factors lead to corrosion:
• Acidic compounds contained in the air, such as
carbonic acid and sulphur dioxide, combined
with oxygen from the air and/or water. Salts
such as sodium chloride used as road salt
accelerate the corrosion process.
• Mechanical damage such as stone chips and
scratches which penetrate through to the steel
panel.
• Lack of care by the vehicle owner of the painted
and corrosion proofed surfaces or areas on the
vehicle.
• Unfavorable weather or environmental
conditions, as may occur in areas with high
humidity, high salt content in the air or serious
air pollution due to aggressive gases and dusts.
In the case of mechanical damage, formation of
rust can often be seen, beginning to spread into
the painted surface from a point (stone chip) or
from a line (scratch). If these faults are not
professionally rectified in good time, the result is
rusting through from the outside to the inside.
Rusting penetration from the inside to the outside
occurs when for instance the cavity protection was
inadequate.
Operations after painting
NOTE: The manufacturer's instructions must be
followed when working with the various corrosion
protection materials.
• After painting, treat all cavities in the repair area
with cavity protection wax. In doing so, pay
particular attention to the weld seams. In
dead-end applications with a panel insert, the
cavity protection wax must be applied so that it
also reaches the area of the panel insert.
• Seals which were applied in production and not
over painted must be reapplied. Seals protect
vulnerable parts of the bodywork, keep moisture
away, reduce wind and road noise and dampen
vibrations.
• Apply transparent wax.
Definition of the degree of rust
In workshop practice, in order to be able to carry
out a consistent and objective evaluation of the
scope of the damage, a degree of rust on the scale
of 1 to 5 is determined by the DIN 53 210 standard.
The main criterion here is the extent to which rust
exists under the paint structure. It is determined in
millimeters (mm).
G506675en
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Paint - General Information
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DESCRIPTION AND OPERATION
chapter 501-25
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