The Stovebolt Site Forums The Shop Area Paint and Body Shop Using Ospho

I've had much success with Carl's approach Alvin. I use one of those cup wire brushes on an angle grinder. It will get you down to bare metal. Post ospho treatment depends on the one you use. Some do advise washing down with water to neutralize. The one I use does not. So I just wipe with acetone, let dry and paint. In my experience, almost all rust treatment or metal treatment products use a variant of phosphoric acid to chemically convert the rust, even PPG's metal treatment.