paint

What would be the most durable paint for bare aluminum that does not require baking in temperatures higher than that required to turn annodization orange. I need to color grooves in an aluminum flashlight body. Grooves like OL puts in some of his mag mods with a file. I need something that will stay there and not flake off.

Oxidized Aluminum Takes paint VERY well. If you are going to paint a recessed surface (grooves) so much the better.
I will leave it to someone else to recommend the BEST paint.

If I were to do what you are attempting, and the rest of the flashlight is still anodized, I think I would clean the groove with a piece of string soaked in a dilute solution of lye or other caustic cleaner. Be careful not to get any on the anodizing. The lye will oxidize the groove. To rinse, put the part in a bucket of water and shake it while in the water. A large enough amount of water will dilute the lye in the groove so as not to corrupt the rest of the anodized part. Use a second piece of string soaked in WATER to “power” rinse the groove and remove any residue.

Sears used 2 sell a diy power coat system that u baked in a regular oven. Not sure if it’s still available thru them, but u might want 2 check it out.

On bare aluminum, I just make sure the surface is rough, not shiny (120 grit, versus 400 grit, for an example). Then I clean it with paint thinner and alcohol after that. Once it dries, I paint with Rustoleum textured paints. They are the only ones I use. I haven't tried much in the way of other paints, so I can't say how good they are. I mask off with a good painter's masking tape.

I know people have a problem sometimes with paint not sticking to Aluminum. I have never had that problem, but I could not tell you why. I sand the area, wash it with the paint thinner and then with the alcohol, let it dry off, or blow it dry and mask and paint. I don't wait for the aluminum to form an oxidized layer first, but I do not know if that helps or hurts.

I bake Rustoleum with two incandescents lights. The temps don't get higher than a couple hundred degrees and I bake it for an hour, then I back the lights off. If using an oven, I would go 200 for an hour, then 150, for a half hour, then let it cool off by turning the oven off and leaving it in there, till the oven cools. Even with baking, it will take 48 to 96 hours before the paint is fully cured.

Epoxy or Zinc (primer, then color) is what you use over alu but since it is recessed you could just use dupli-color, rust-oleum etc. for alum paint. If it is a real nice light I would epoxy prime then paint.

Keith

Thanks for the tips guys. Budy, that’s interesting about the epoxy primer. That sounds like it would be very durable. What kind of epoxy? Just regular two part epoxy or some special product?