Maintenance
Suitable and timely maintenance is
required to ensure optimum performance of a coating system. However, choosing a
coating system for the purpose of maintaining an existing object is more
complicated than for a new object.
The choice of a suitable maintenance
system is based on the following criteria:
atmospheric circumstances
nature of the existing coating
type and condition of the existing coating
nature and type of substrate
In general, epoxies, chlorinated
rubbers, vinyls or polyurethanes should not be applied over alkyd paints out of
concern for possible softening and poor adhesion.
Alkyd based paints should not be
applied over aged chlorinated rubber and vinyl paint systems out of concern for
possible cracking. They should also not be applied over zinc-rich primers in humid
conditions out of concern for the risk of saponification
For each maintenance specification,
the compatibility of the maintenance coating system with the existing coating
system must be known or else determined with the help of a test surface.
Some of the most common paint
failures are:
cracking
blistering
poor adhesion
corrosion
It is important to determine the cause of failure in a coating system, especially if it occurs at an early stage. The atmospheric circumstances then need to be determined anew to be able to recommend a suitable paint system. Inferior paint films need to be removed in case of poor adhesion. Aged but intact paint films need sanding at all times to secure proper adhesion of the new paint system.
