How to Paint Over Rusty Sheet Metal

Rust leaves a reddish-brown tinge on sheet metal.

Sheet metal consists of flat metal panels used commonly for large expanses of roofs. Although sheet metal is generally durable and long lasting, steel and iron are not impervious to rust. Rust forms when scratched or dented portions of sheet metal are exposed to carbon dioxide, oxygen and water. If neglected, rust permeates through sheet metal until the panels eventually weaken and deteriorate. Thoroughly remove all rust particles from sheet metal before painting the surface.

Things You'll Need

• 2 towels
• Coarse-grit sandpaper
• Sanding block
• Steel wool pad
• Mineral spirits
• Rust-inhibiting metal primer
• Paintbrush
• Acrylic latex paint

Instructions

1. Rinse the sheet metal with water to remove loose dirt and debris particles. Thoroughly dry the metal with a towel.

2. Wrap coarse-grit sandpaper around a sanding block. Rub the block back and forth over the sheet metal until the rust is completely removed.

3. Saturate a steel wool pad with mineral spirits. Rub the pad over the sheet metal to remove sandpaper dust buildup and prepare the surface for paint.

4. Rinse the metal with water to wash away the mineral spirits and loosened grime. Dry the metal with another towel.

5. Coat the metal sheet with rust-inhibiting metal primer to protect the surface from rust. Apply the primer evenly over the metal using a paintbrush. Let the primer air-dry completely according to the manufacturer's directions.

6. Apply two coats of acrylic latex paint over the metal primer for aesthetic appeal. Allow each coat of paint to air-dry for the time span advised by the paint manufacturer.

Tips & Warnings

• Substitute an orbital sander for the sandpaper and sanding block. Operate the orbital sander as instructed by the manufacturer.

References

• Home Tips: Sheet Metal Roofing
• Home Tips: How to Repair Scratched or Corroded Aluminum Siding
• House Task: Removing And Preventing Rust