sheet metal/paint technique question

please do not use any rattle can primers. I work at a body shop and we just had a 72 stang came in that some guy did all his own work...terrible.

First off, before I started doing this kind of stuff I was all for DIY, but after having to fix peoples stuff its a REAL big hassle, I can even see your point of view of wanting to keep costs down but a paint job is only as good as the products underneath it. Cheapo primers from a can(maybe not all but all I've seen) have NO FILL, its as I put it basically a thick guide coat. Say you weld in a patch, and say your a ok welder, and have no access to sand blasting, well when we get done welding we grind it down then sand blast the seam to inspect for any pin holes, make sure all of these are gone, then apply a fiberglass reinforced body filler, typically called mars glass or dura glass, over the weld seams to make them water proof and resist cracking. Oh and never apply any filler over any paint, glazing putty can be applied over paint as long as it is scuffed.

The best method to start out in my opnion would be to first get an air compressor, even rent one and it will be fine for just shooting primers but probably not ok for paint/clear cause it wont keep up on the air pressure. In my car I'm stripping ALL of the paint off of it, you never know what some 'hack' did back in the day or if that paint isnt going to just flake off some day, better to be safe the sorry, So get all the paint off then start by pulling dents using a dent removal gun or welding in patches, if for some reason you have to do the old fashion way of pulling dents of drilling a hole and using a screw to pull it out, weld the hole up, there are all sorts of old cars out there fixed this way and have 'worm holes' going though the metal with mud hanging inside, terrible way to fix things. Use a good quality body filler no 'bondo' and a good glaze, it does suck since I know its expensive but hey these things are expensive as hell. After the body work is done, assuming you didnt strip the cars paint, We apply polyester primer, it has a high build and sands great, Its actually Transtar brand, all of there products are great along with Upol Part number is 6541-g I believe, works great, Then block sand your work, along with feel it every way you can, up and down, left right, side ways, I say this cause Doing that mustang at work, the guy felt stuff Horizontal, which was ok to say the most, but once you felt it up and down it was way messed up.

Oh and I was going to mention, about primers, do your body work apply epoxy primer or a high build primer from a roller, and that way no need for a compressor, a body shop can just pick up where you left off and you know the stuff will hold out problems(epoxy will anyways for sure) Then the body shop can just sand it(epoxy) spray a blocking high build primer on it and start off where you left off, That would be the best way for a DIYer to do IMO. No rattle cans, no bondo, no problems!

I know I typed a book here for you so i'll stop and allow you to ask questions if you want Pm me is typically the best way since I may forget about the thread.

Good luck,
Jack