Q: I wish to paint with acrylics on a raw aluminum surface.
Which surface preparation/priming is necessary? Also, I may not cover
the entire surface with paint. What type of varnish or sealant should I
use on the acrylic-painted portion and on the raw aluminum portion?
A: Metals are smooth and need to be treated to develop a
tooth that will accept paint. I suggest sanding the metal to create the
tooth. Aluminum accepts acrylic paint because the metal and the acrylic
have similar reactions to changes in temperature, and a paint-aluminum
reaction provides a very good adhesion. You may also want to sand the
unpainted areas to accept the final acrylic varnish.
--by Camille LaPointe-Lyons