The Stovebolt Site Forums The Shop Area Paint and Body Shop phos acid, how should it look when done

Phosphoric acid will retard rust, not prevent it. The orange stuff is rust. Do not rinse with water, just apply a thin, even coat and let it sit. The resulting surface will be less prone to rust but if it gets wet it will rust.

I stripped my hood and treated it with phosphoric acid and left it outside... BAD mistake! It rained and just enough rain got on it that it completely rusted all the bare metal to the point of leaving an outline of the hood on the concrete floor of the car port.

My best advice is to hit it with the acid, let it sit overnight and get a coat of primer or something on it to prevent rusting. I've been using Eastwood Rust Encapsulator with excellent results. I'm absolutely sold on the product. It works as advertised, beat POR15 in an independent test and is lacquer based for quick clean up.