[How-To] Priming Aluminum for paint?

[motormech1]

Alodine is the gold standard for aluminum prep but, as pointed out, it's nasty stuff. I've painted planes with and without it during prep and I'm not sure if I'll ever know if it made a difference since the paint jobs will probably outlast me. I know when I worked on big planes they used an acid etch and then alodine before priming. For a shop tool, I think you'll be good with a primer designed for aluminum. My guess would be that it's of the self etching variety. I would probably just powdercoat it. Post some pics, I'd love to see it!

 

[randyjaco]

Found a technical process bulletin:

https://www.aircraftspruce.com/catalog/pdf/09-01628tds.pdf

Again, the health hazard is there. So it’s your decision.

But the shop floor knowledge (which isn’t always correct…) is just that you need clean aluminum. No corrosion or oil etc. You just brush it on (we used the pens for touch up mostly) and let it dry. Kind of like wiping something down with paint thinner.

The sanding/blasting only makes sure you have clean metal and a tooth for the paint.

Whatever you decide on, make sure you document it here for us! I know I want to see it

Edit:
Interesting, that document pretty clearly states that it should be water rinsed BEFORE drying to avoid salt powders affecting paint adhesion.
Hmmm….

That would definitely make things difficult. I wouldn’t want to wash that stuff off in the driveway and make your house a superfund site!


As an entirely 3rd option… you could take it to a chem process shop that does it for you. It would be dunked in the vat and come out professionally coated. No idea if you have any ‘chrome shop’ type business around you or what the price would be. It’s another good option though!

Yeow, that stuff looks scary. I will check to see what a professional application costs. I sent a Customer Service request into Rustoleum to see what they recommend.