The paint you see, the top coat, is often part of a paint "system" in which
the parts combine to give a decorative long lasting, hard wearing protection to the surface beneath. Commonly, a paint system will include two or more of the following components:
Primer: Prevents corrosion, adheres to and penetrates the surface and
provides a sound key for the next coat.
Prevents contaminants coming to the surface and prevents other
coats sinking in to the surface.
Undercoat: Hides the previous colour, fills minor imperfections, gives a
uniform surface, sands easily and promotes adhesion.
Top Coat: Provides the primary protection layer and decorates.
Which Paint Where?
Filler: Used to fill imperfections and level the surface.