Question about spot painting

[Shogun187]

It's my understanding that old CARC can be a decent surface for repainting. My truck has a few place missing paint and I'm wondering what's the best way to address the aluminum that's showing - chemical strip that small area, sand it down lightly and repaint, or just paint over the bare spots?

Most of the info I've found seems to only address large areas, whole truck etc.

 

[riderdan]

Paint doesn't like to stick to bare aluminum, so even for spot painting you should prime first. I've used zinc chromate primer (in a rattle can) on some rivets that were bare aluminum, then spot painted with the CARC-matching rattle can green/black paint. The most important thing, as with any paint job, is to be sure that the surface is completely clean. And remember not to use a non-aluminum metal tool (wire brush/wheel) when doing the prep work.

 

[Shogun187]

Paint doesn't like to stick to bare aluminum, so even for spot painting you should prime first. I've used zinc chromate primer (in a rattle can) on some rivets that were bare aluminum, then spot painted with the CARC-matching rattle can green/black paint. The most important thing, as with any paint job, is to be sure that the surface is completely clean. And remember not to use a non-aluminum metal tool (wire brush/wheel) when doing the prep work.

Thank you for the reply. So, a safe bet would be to sandpaper on the bare spots to feather with the nearby paint, spray the rattle can primer to cover the spots and then paint over? Is there a need to reapply alodine? I've found some in small pens but didn't know if it was necessary.

 

[riderdan]

I don't think you need the alodine if you use a good primer. It's a corrosion inhibitor/paint adhesion thing, and on well-cleaned bare aluminum it shouldn't be necessary to use that before primer.

My knowledge is mostly from auto-body painting classes I've taken at the college where I'm working on my auto restoration degree. Hopefully someone with a lot more humvee painting experience will chime in...