Lacquering and painting (Topic 11049)

The most important part of a good paint system is the pre-treatment. If the quality of the pre-treatment is not good enough, any high quality paint will delaminate or deteriorate in some manner when exposed to a corrosive atmosphere.

The first step should always be washing or degreasing. Subsequently, in order to get good adhesion, etch primers or abrasive blasting with non-metallic media, like glass or alumina, may be used in addition to conversion coatings, as a pre-treatment to a lacquering system.

Generally baking coating systems are superior to air dry coating systems with regard to corrosion protection, because the baking system will give a better penetration of the surface treatment and will have better combination of flexibility, scratch resistance, gloss retention and fewer defects. When specifying a baking system, one should be aware of the yield strength increase the aluminium may experience because of the ageing in the baking oven if this is prolonged, but such changes are normally slight.

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