Paint Rusted Metal, Use Phosphoric Acid & Clean Tacky Surface on Seawall

Metal seawalls can be treated for rust using phosphoric acid. Phosphoric acid is a non-flammable, water-soluble liquid that reacts with rust to form a protective layer of iron phosphate. This layer inhibits further corrosion and can help to extend the life of the seawall.

To use phosphoric acid to treat rust on a metal seawall, you will need to:

Clean the seawall surface to remove any dirt, debris, or loose paint.

Apply a thin coat of phosphoric acid to the rusted area using a brush or roller.

Allow the phosphoric acid to react for at least 30 minutes, or longer for heavier rust.

Rinse the treated area with water to remove any residual phosphoric acid.

Apply a primer and topcoat to the treated area to protect it from further corrosion.

It is important to wear gloves and eye protection when working with phosphoric acid as it can irritate the skin and eyes, and it can also be harmful if inhaled.

Here are some additional tips for using phosphoric acid to treat rust on a metal seawall:

Use a concentration of phosphoric acid that is appropriate for the severity of the rust. For light rust, a 10% solution of phosphoric acid should be sufficient. For heavier rust, a 20% or 30% solution of phosphoric acid may be necessary.

Be careful not to over-apply phosphoric acid. Too much phosphoric acid can damage the seawall surface.

If the seawall is painted, you will need to remove the paint before applying the phosphoric acid.

You can use a paint stripper or a wire brush to remove the paint.

Once you have applied the phosphoric acid, be sure to rinse the treated area thoroughly with water.

Any residual phosphoric acid can continue to corrode the seawall.

After rinsing the treated area, be sure to apply a primer and topcoat to protect the seawall from further corrosion.