Corrosion of Paint
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TabLE 7.13
Multilayer Paint Systems Requiring Commercial Blast (SSPC-SP-6) for Surface
Preparation
System A Inorganic-Zinc/Epoxy Mastic
Paint Layers:
One coat inorganic zinc: 2–3 mil dft (50–75 μm)
One coat epoxy mastic: 4–6 mil dft (100–150 μm)
Properties:
Zinc primer provides outstanding corrosion resistance and undercutting resistance
A barrier protection for the zinc primer is provided by the finish coat of epoxy, which also
provides a color coat for appearance
Suitable for use on carbon steel only
Limitations:
A relatively high level of applicator competence required for the primer
System B Inorganic Zinc/Epoxy Primer/Polyurethane Finish
Paint Layers:
One coat inorganic zinc: 2–3 mil dft (50–75 μm)
One coat epoxy primer: 4–6 mil dft (100–150 μm)
One coat polyurethane finish: 2–4 mil dft (50–100 μm)
Properties:
Zinc primer provides outstanding corrosion resistance and undercutting resistance
The zinc primer is protected by a barrier coating of epoxy primer, while the finish coat of
polyurethane provides color and gloss retention
This is a premium industrial finish for steel surfaces
Can only be used on carbon steel
Limitations:
A relatively high level of applicator competence required for the primer
System C Inorganic Zinc/Acrylic Finish
Paint Layers:
One coat inorganic zinc: 2–3 mil dft (50–75 μm)
One coat acrylic finish: 2–3 mil dft (50–15 μm)
Properties:
Zinc primer provides outstanding corrosion resistance and undercutting resistance
Water-based single-package finish has excellent weathering and semigloss appearance
Limitations:
A relatively high level of applicator competence required for the primer
The finish coat has low temperature curing restrictions
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