Ok. So i got the rear of the plane all primed and painted (on the inside) and while I was blowing out some aluminum shavings, I ended up seeing the paint peel off.
The surface was cleaned, the paint did not ripple - looked fine. Just when a standard air blower off my compressed air tank was used, it peeled up.
Thoughts on a cause? I used a solid etching primer (Dupli-Color Pro Automotive Primer), and then a top coat with a basic Rustoleum pro black enamel.