I am unsure if this is the right forum to post in....but here goes. I paint helicopters. I recently painted an aluminum tail boom with a glossy orange automotive paint (martin senor). Before painting, the aircraft was stripped of all old paint using orbital sanders and a die grinder around the rivets. When I was through with that, we wheeled it into the paint shop. Once it was there, I wiped the whole thing down with a wax and grease remover. Then, I scuffed the whole tail boom with the green scotch brite pads. Then another wipe down with the wax / grease remover. When the prep was done, I used a green self etching primer (reduced with etching reducer), and proceeded to spray 2 coats on the tail boom. After sanding and fixing any little spots that needed it.. another coat of primer was sprayed, and all looked fine. I used the orange paint, fast reducer and hardener in the final mix. Equal parts reducer and paint to 1/12th hardener. Sprayed a coat of orange paint.. let it dry. There was a couple rivet runs that needed fixing, so after fixing those, a second coat of paint was added. When that was done, it was a pretty looking tail boom. However, when the customer decided they didnt like orange.. they went to scuff it so they could repaint.. and when they started to scuff it.. large flakes of paint & primer came off. My paint wasnt sticking. So, the temperature seemed was right when we painted, self etching primer, and good paint coverage, yet, something is not right. Barring the possiblity of a bad batch of primer (seems unlikely) does anybody have any ideas or guesses as to what went wrong here. I am determined not to run into this problem again. I used to paint houses, and I never had this sort of problem.