An Etching Tip:
I found out some years ago that I ran across the same problem of P.E. users had. Paint staying on parts! Well, I tried everything I could think of and read about. I tried something out of desperation. You have all heard of White Vinegar, Right? Not to be confused with WINE Vinegar!
Soak the parts on the fret 24 hours in full strength White Vinegar. Then rinse and wash throroughly with warm water and Dawn regular detergent, using a Baby, Extra Fine toothbrush Gently on the parts. NO heavy pressure here, or, you will bend the parts!
Prime with a Thinned Mixture of Primer. You Must either thin your paint BEFORE airbrushing,By fifty Percent or hand Brushing By Seventy Five percent before painting! The paint will flow on like water and in some cases look to thin.That's okay.The primed surface is prapped. Now paint as usual when the primer has cured to the Vinegar etched surface for at least 24 hours after air drying in a dust free containment area!
Yes, my fellow modelers. You cannot see it. The Vinegar microscopically etches the surface of the metal parts you want painted. Oh, another note: Bend and or Curve your parts BEFORE painting. Or Paint will Chip off. Ever seen a bent Fender? A sharp bend always, Well mostly, result in paint failure and chipping!