How to Use Acid to Remove Rust

Rust is caused when water makes extended contact with a metal surface or water with a high iron content is allowed to sit on a material that is prone to oxidation such as porcelain. Rust in the home most commonly occurs in bathrooms within the sink, toilet, or shower. Acid is particularly effective in rust removal due to its ability to eat away at surface corrosion. Depending on whether the rust appears on a metal surface or a non-metal surface, different types of acid should be used to break down the rust and remove it successfully.

Things You'll Need

• Naval jelly
• Gloves
• Protective eyewear
• Paintbrush or sponge
• Wire-bristled brush
• Dry cloth
• Hydrochloric acid-based cleaner
• Nylon-bristled brush

Instructions

Removing Rust on Metal Surfaces

1. Purchase a container of naval jelly. Naval jelly contains phosphoric acid, which will dissolve the rust present on metal surfaces.

2. Put on gloves and protective eyewear. Phosphoric acid is extremely caustic and can burn your skin and eyes in the event of an accident.

3. Apply the naval jelly liberally to the rust stain using a paintbrush or sponge. Naval jelly is very thick and sticky. Because of this, you can use it on a non-flat surface without fear of it dripping.

4. Allow the naval jelly to sit on the surface for up to 20 minutes, depending on the amount of rust to be removed.

5. Scrape the oxidation away with a wire-bristled brush.

6. Rinse the area with water and pat the surface dry with a clean cloth.

Removing Rust on Non-Metal Surfaces

1. Purchase any household cleaner that contains hydrochloric acid. Although not as strong as phosphoric acid, hydrochloric acid can be used on most any surface without risking acid damage.

2. Put on gloves and protective eyewear. Hydrochloric acid is weaker than many other forms of acid but may still cause damage to unprotected skin and eyes.

3. Pour or spray the chemical onto the rusted surface.

4. Allow the hydrochloric acid to sit on the surface for approximately ten minutes.

5. Scrub the rust away with a nylon bristled brush. Wire brushes may scratch non-metal surfaces and force rust particles into the crevices. This makes the rust much more difficult to remove.

Tips & Warnings

• Some rust stains may require more than one acid application to remove.

• Never attempt to use acid to remove rust in an area that is not properly ventilated. The acid fumes will accumulate in an enclosed space and can be toxic.

• If you leave naval jelly on a rusted surface for minutes the phosphoric acid will begin to eat away at the metal, resulting in etching.

• Do not use bleach to clean rust. Bleach sets rust stains.

References

• Iron and Rust--The Stainers
• Naval Jelly

Resources

• Naval Jelly Rust Dissolver