Apply a rust converter for paintable surfaces

Brush or spray a phosphoric acid converter (Ospho, Corroseal) onto rusted steel after removing loose flakes. The converter transforms red iron oxide into stable black iron phosphate over 24 hours, creating an excellent primer surface for paint.

Why It Works

Phosphoric acid chemically converts rust into iron phosphate, a hard, inert compound that bonds to the base metal and stops further corrosion. Unlike removers, it transforms rust in place rather than stripping it.

Tips

• Ideal for items you plan to paint — vehicle frames, fences, railings, outdoor furniture
• Remove loose, flaky rust first with a wire brush — the converter needs solid rust to react with
• Use oil-based primer over the converted surface — latex paint adheres poorly to iron phosphate
• Apply in temperatures above 50°F for proper curing
• Not suitable for food-contact surfaces or tools that need bare, polished metal
• Don't let the product dry on the surface before it has cured — causes white residue