Primering my car?

[1973mach1]

My cars starting to rust since I started sanding it down and have it under a tarp, I want to primer it now and try doing the body work one it. I have a few questions, some of the old bondo has scrapes in it and has holes in it, can I just patch it up with more bondo or should I take it all off and start from scratch, also im planning on using a paint gun to primer it, were can i buy jars of primer to use? Most I see comes in spray cans. IM guessing I should do 2 coats then sand the primer down smooth and it should be ready for painting? Right now I did alot of the sanding with an electric sander but still have some more work to do, im buying a compressor tommorow so a pnuematic sander should help me finish alot faster. After im done sanding and before primering the car should I use water to wipe off all the dust? I know it wont be perfect but its not a show car so as long as it looks OK i'll be happy.

Thanks,
Jim

 

[oboebrian]

Ok, there are four major types of primer out there (then for 3 of them low build, medium build, or high build variations):

1) Spray Can Primer- Should not be used except to protect a surface in high humidity for a day or two at the max.

2) Primer Etcher- This is sprayed on clean bare metal only

3) Primer Sealer- This is sprayed on top of smoothed (very lighly sanded) primer etcher. This is what actually protects and seals the metal from rusting. A Tip is to substitute one part of the primer sealer for one part of your base color (unless you have black primer sealer). This way if you get a chip in the paint, the primer sealer is tinted the color of the car and won't show as much.

4) All in One system- This primer sealer can be sprayed directly onto bare metal and protects the metal from rusting.

As to the low/medium/high build aspect. For most of the car you'll go with the low build. If you have a lot of scratch marks from sanding or stripping the car, go with the medium build. If you weren't stripping the car totally, and had orangpeel, small pinholes, or large scratched, use either the medium primer for most of the car and the high build primer for the bad areas. Then sand, sand, sand (of course)!

As for cleaning the metal, get many, many tack cloths. Also get a gallon of silicon & wax remover such as SuperKlean or some other substitute. Using a regular terry cloth towel and or compressed air, blow out all crevices of the car and then the main panel. Wet the ground thoroughly all around the area you’re primering (till it’s muddy), this keeps the dust from being kicked up.

Then wipe down the car using paper towels and the SuperKlean (with clean nitrile or rubber gloves on, don’t touch the car at all with our clothes or skin). Be very generous with fresh paper towels and the solvent. I usually go over the car twice. Then right before spraying (i.e. with the primer in the gun, which happens to be in my other hand or ready to go) wipe down the car a couple times with the tack cloths. Again be generous about using fresh tack cloths.

Then you’re ready to spray, of course you have to make sure you are not dusty, able to drip sweat, or touch any part of the bare clean metal with you’re skin. This will keep you’re work surface super clan with hardly any dust particles or fisheyes.

 

[1973mach1]

Thanks for the tips, I dind't sand the car down to bare metal I just sanded it smooth, it is bare in a few area's though. But mostly I just sanded down the original paint alot to get it smooth, Can I paint on top of this? The only area's I sanded down to or really close to bear metal was the front fender.

Thanks,
Jim

 

[oboebrian]

Then I'd suggest you get the primer etcher/sealer combo (that works with you're paint system). Then spray oen coat (not thick wet coats), then the sencond coat slightly thicker until the car is uniformly covered. Then take a contrasting spray paint color and lightly mist a 'guide coat'. Start sanding again. The areas that dissapper fast are high areas, the areas that still have the paint where all the paint from the guide coat is gone is a low area. Fill this low area, and sand or work the high areas down. then do another guide coat. Sand again.

Once all teh panels are straight again. Spray the last coat of the sealer. Then the base color, (andy graphics) then the clear.

I hope I've helped.. this reply isn't as long because i'm in the middle of a class at college