Originally Posted by
jwzumwalt
I have been a pilot and A&P for over 40yrs in Alaska.
I have used epoxy paint (one and two parts), urethane, and powder coating.
For certified aircraft I used Dupont Imron for the first 20yrs but due to high prices,
I now use generic urethane.
My conclusion...
I have never found any zinc chromate that works very good; not even epoxy zinc chromate.
All of them quickly develop cracks and a zinc chromate surface can compromise a riveted joint.
The FAA prohibits paint between a rivet joint - even though everyone does it.
Powder coat is better than any other for durability.
So I powder coat instrument panels, engine parts, wheel rims, handles & knobs, etc.
And yes I have even used Harbor Freights cheapo system that works some what ok.
(It does tend to clump and be uneven)
Poly Urethane looks the best by far and the paint formulas are almost as good as epoxy.
So, I poly urethane when looks are important and powder coat when toughness is needed.
I never zinc chromate, I use alodine instead.
I moved to Southern Idaho 5yrs ago and now have to contend with desert heat. I have not
encountered any problems that make me think the warmer temperatures will require me
to change products or technique.