I've painted a large majority of a work truck over the last couple years. I painted it due to some panels completely rusted out (replaced rockers), a few front end accidents, and scratches all over the cab. Since then, I've noticed bubbling in some very small areas with new rust about to come through, some minor peeling right next to new scratches that went down to the metal, and the plastic upper bumper cover seems to chip very easily. Since its mostly a work truck my main concern at the time was just fixing what was horribly wrong, and getting it driveable again after accidents. Now that I'm seeing all these minor issues a couple years later, I'm wondering how I can improve in the future. My final sanding on all panels was 320, I'm sure I cleaned them properly before paint. I'm fairly new to all of this so I'm just looking for some advice on how I can take a decent paint job, that had good adhesion and no problems for the first two years, and make it better next time.

What brand of materials did you use?
What steps did you follow when prepping and painting?

hweb30 wrote:so I'm just looking for some advice on how I can take a decent paint job, that had good adhesion and no problems for the first two years, and make it better next time.

The best thing for adhesion and durability, is to use a good epoxy primer
for your paint to go on.
I do a lot of bumpers and putting epoxy on before paint
has reduced road rash a lot.

'68 Coronet R/T wrote:What brand of materials did you use?
What steps did you follow when prepping and painting?

I sanded with a DA 320!grit and cleaned with wax and grease remover. I use nason Acrylic sealer, Base and clear

Paint adhesion is really only as good as the foundation it is applied over. This is one reason that repaints and touch ups often fail early on. It isn't that they didn't adhere well but that the paint it was applied over has continued to deteriorate.

A quality epoxy primer applied directly to the metal/plastic is the best foundation for a long lasting paint job.

In some cases you can sand off the old paint down to a level that you are confident is still well adhered and then shoot epoxy primer.

Aside from the epoxy primer, should I still sand with 320? Or can I get away with 220?

Generally you would prep the metal with 80 grit on a DA, then shoot your epoxy.
Filler work would be done over the epoxy and then sealed with another coat of epoxy.
2 - 3 coats of 2k primer applied directly over fresh epoxy (up to 7 days) without sanding.
Guide coat and block sand with 150-200 to remove guide coat.
Wet sand with 320 then with 600, clean, dry and shoot your color coat.