Artist wants paint suggestion for aluminum

I would like to create artwork on aluminum sheets and wonder the best paint to use -- enamels, oil based or acrylic or any suggestions? Do you know if these will discolor over time. I would plan to varnish after painting. thanks.

Acrylic would probably work best I think, it will keep solid color the longest and won't flake off too easily. Regardless of what paint you use it will eventualy flake off, metal is not a pororus medium and has a tendancy to repell water/liquids.

Aluminum art has been my passion for a few years. I use flat aluminum sheeting which is sanded, cleaned, painted with an auto base paint which is transparent, and then painted. I am an abstract landscape aluminum painter. Website is http://www.darleanmorris.com

My challenge is to keep the frames that I use to look polished instead of dirty. The frames I use are really L-brackets cut on the 45 to form a frame. The are approx. 2.5 inches wide on each side of the bend. I actually use a gorilla glue to fuse the sheet onto the bracket.

My process has worked well for the 3 years that I have been working with this substratum.
However, the frames look worn and tired. I need them to look finished and polished. Any suggestions?