I go through this process when prepping for paint.
1. Wash with degreaser and scrub brush and rinse with water.
2. Wire wheel or media blast the part
3. Immediately spray with 100% Phosphoric Acid (I get it from Home Depot) and let it sit for a few minutes. Wipe off with a dry towel. If there is still some rust repeat until it is gone or has turned sufficiently dark grey. I never wash the parts with water again, guaranteed flash rust. Let part completely dry.
4. Scuff off any white residue that might remain. Run an exacto knife in small crevasses.
5. Dampen (not dripping wet) a cloth with 100% acid and wipe part down.
6. Wipe part down with PRE or Lacquer Thinner.
7. Paint with epoxy primer asap.
8. Top coat when time permits.
I have never soaked a part overnight in this stuff, though it says you can do that. Don't let the acid dry on the part, that is when you get the white powdery stuff which I am sure isn't good to paint over. I have done this process with some great success. It is tedious but preparation is 95% of the job.
Last edited by jomichael; 02/20/2008 9:21 PM.
