3.5.1 The application of a coating should be a
well planned activity, integrated in the shipyard's construction plans
and carried out under controlled conditions to avoid conflicts with
other yard operations.
3.5.2 Coatings, including the primer and intermediate
coats, should be applied on surfaces prepared and checked according
to the provisions of 3.3 and 3.4.
3.5.3 Coatings may be applied by spraying in controlled
humidity and surface temperature conditions, in accordance with manufacturer's
recommendations. Additional stripe coats, if required by the job specifications,
should be applied by brush or roller to welds, edges and areas not
easily accessible.
3.5.4 Areas where the shop-primer is damaged in
any way may be touched up in accordance with the manufacturer's specifications.
3.5.5 Each coating layer should have the maximum/minimum
thicknesses in accordance with the coating specification. An 80/20
practice may be adopted, which means that 80% of all thickness measurements
should be greater than or equal to the nominal dry film thickness
(DFT), and none of the remaining 20% is below 80% of the DFT.
3.5.6 Care should be taken to avoid increasing
the thickness in an exaggerated way. Excessive thickness could lead
to dangerous consequences, such as solvent and thinner retention,
film cracks, gas pockets, etc. Wet coating thickness should be checked
during application.
3.5.7 Each coating layer should be adequately
cured before application of the next coat, in accordance with coating
manufacturer's recommendations. Intermediate coats must not be contaminated
with dirt, grease, dust, salt, over spray, etc. Job specifications
should include the dry-to-re-coat times given by the manufacturer.
3.5.8 Thinners should be limited to those types
and quantities recommended by the manufacturer.