How to handle flash rust

[dgunn]

I sand blasted some steel parts, then treated hard to blast spots with phosphoric acid. A final water rinse created a very thin rust film called flash rust. What's been other's experience with dealing with flash rust when prepping for painting.

 

[RayF]

Take your Phosphoric acid, and mix it 50/50 with Isopropyl alcohol (90%+). Put this in a spray-bottle.
Spray the flash-rust and wipe immediately with a lint-free rag (I use red shop towels). Blow the surface off with compressed air (it blows away any "fuzzies")... and tack with a tack-cloth before painting.
I recommend an epoxy primer, or a self-etching primer.

EDIT: wear rubber gloves...lol

 

[digger]

I sand blasted some steel parts, then treated hard to blast spots with phosphoric acid. A final water rinse created a very thin rust film called flash rust. What's been other's experience with dealing with flash rust when prepping for painting.

Why not just blast'um and wipe them down with lacquer thinner and forget it, till you prime?

 

[dgunn]

In a few hard to reach areas I could see rust still sitting in the pit in the metal which is why I treated the part with the phosphoric acid. The phosphoric acid I use is a product called Rust-Mort. The directions say after drying for 24 hours to then rinse off with water. So after I did that I toweled off the parts and put them in low heat to dry off any remaining moisture. That's when the flash rust occurred .