Best Method For Exposed Primer?

[Dieselhead]

For a project I will be starting soon, my vision of it shows it having some panels where paint has chipped off, exposing bondo/primer. A quick look at most other weathering techniques goes straight to full-on rust and rot, which is not what I'm looking for. Would a normal chipping method work for the desired effect? Has anyone else gone for this look? If I figure it out I'll be sure to post my method so others can follow. Thanks.

[Mike999]

I've tried that because I wanted to show rust on the bottom, remains of primer and finally remains of the original factory paint. As I remember, here's what I did and it worked pretty well. It does take some time and practice:

1. Spray base rust coat. I usually start with Krylon or Rust-o-leum rusty reddish-brown, followed by different rust colors for variety. Let this dry COMPLETELY, at least 24 hrs. 

2. Spray Dull-Cote clear lacquer or similar to protect the rust.  Also let that dry at least 24 hrs.

3.  Spray a coat of hair spray. The longer you let the hair spray dry, the harder it will be to remove. This works to your advantage. If you want to show a lot of rust under the primer, only let it dry a half-hour or so. If you want more of the primer to show and not so much rust, let it dry longer. 

4. Spray a WATER BASED ACRYLIC gray primer, or several coats of different shades. Maybe dark gray on the sides/rocker panels, lighter gray on top where the sun would fade it on a real car. This must be water-based paint, because water will remove both the acrylic primer paint and the hair spray underneath it.

5. Wait a few minutes for the primer to dry. Then dip a small brush in water, and carefully start scrubbing the primer coat. The water should lift off the primer and hair spray, exposing the rust base coat. The size of the brush depends on how much primer you want to remove.  For scratches, attack the primer with a wet toothpick or any very small, sharp tool.

It's easy to overdo this step and remove too much primer. Don't ask how I know this...

6. When the primer over rust looks the way you want, again spray it with Dull-Cote clear lacquer to protect the rust/primer coat. Let that dry 24 hrs.

7. Repeat steps 3 thru 6 above for the final paint color. Which again must be water-based, so it will react with the hair spray and water.

Good luck!

[Bainford]

I have not attempted to do this, but if I were to try, I think I would spray the body with the primer of choice, then once dry, apply small amounts of liquid mask with a detail brush, or even a toothpick for tiny chipped paint areas. Then paint the body, and once the paint has cured, remove the small bits of liquid mask. It helps to make your liquid mask spots as thick as possible. In place of liquid mask, something like small bits of silly putty might work.

Another thought is the salt method, but I've never tried it and can't comment on a procedure. Perhaps someone who has tried this method will chime in with practical advice on how to do it, and if it would be suitable for this purpose.

[Mike999]

Here's a good video tutorial on the Salt Technique.  Since the OP wants more primer than rust showing, he could add a layer of primer over the rust.  Or even skip the rust layer and touch in rusty patches later, leaving mostly the primer showing.  For patches of Bondo, of course, he can use real Bondo putty from a tube.

 

Edited March 21, 2019 by Mike999
error

[Dieselhead]

Thanks guys. I figured I would have to use some form of chipping coat (I bought a vallejo rust and chipping set for the project, hopefully it works) in conjunction with the salt method, and probably some creative masking work. Just wanted to see if anyone else had found a good way to do it that I wasn't aware of. I'll be sure to show off my results once I get working on it.