Mike:

Get the finished aluminum part Hard Anodized (should be a shop somewhere
near you or at least in Denver). Hard anodize is an extremely tough coating
that will make the aluminum impervious to corrosion, and I believe it can be
done in a variety of decorative colors. If I'm wrong about the color thing,
it certainly can be painted and stripped and repainted if necessary, without
affecting the anodize.

Incidentally, FWIW, Hard anodize is also a very good electrical insulator
while interfering little with the good thermal conductivity of the base
aluminum.

Dan Schaefer