How do I keep the aluminum parts from corrosion ?

[J Tiers]

You guys realize, don't you, that if you paint the OUTSIDE, that is fine, but the INSIDE will still get corroded... and if anything is going to cause trouble, it will probably be something on the INSIDE , not the outer surface.

So you may end up with a nice pretty item, that still fails.

One good thing about oily coatings is that they tend to creep into all parts.... protecting the surface.

That's also the bad thing about oily coatings, in case there is something that should NOT be oily.....

[SGW]

As noted, corrosion resistance depends on the particular aluminum alloy, which you have no control over.

Generally speaking, aluminum is quite resistant to acids, but is readily corroded by alkalines (e.g. lye). In this case, you have no control over what gets splashed up onto the alternator.

If I were concerned about alternator corrosion, I'd probably clean the surface well, prime with a primer specifically formulated for aluminum, and paint

FWIW I'm not particularly impressed by WD40, either. Years ago I bought a gallon of the stuff. After some period of time, I noticed a gooey buildup around the can opening where WD40 had collected and dried. It did not seem like anything I would want to put on precision tools. For your application, buildup of a film on the surface might be a good thing, but I think there are better products available.

[SGW]

Duplicate post.