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 chapter 501-25.
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 |jm and the total system of two-layer on galvanized steel panels must equal at least 105 ^m.
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:
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.