How to Fix Corrosion From Leaks in Air Conditioning Ducts

Rigid air ducts are the only ducts that will rust if exposed to condensation.

Corroded metal air ducts is common when you have a leak in your air conditioner ducts. When the air ducts are not correctly sealed between the joints, the air duct will leak and cause condensation. Removing the corrosion and rust is just part of the solution. Failure to seal the air duct correctly and stop the air leak will result in further corrosion in the future. Luckily you can do both with the right supplies and directions.

Things You'll Need

• Plastic bowl
• Rust remover
• Paint brush
• Spray bottle
• Water
• Mesh scrubber
• Towel
• Metal primer
• Metal spray paint
• Aluminum foil tape

Instructions

1. Turn off the air conditioner to prevent further air leakage through the duct.

2. Pour the rust remover into the plastic bowl, and with a paint brush apply the remover to the corroded air duct. Let the rust remover sit for at least 10 minutes before removing it.

3. Fill the spray bottle with water and spray the air duct. Use a mesh scrubber to remove any loose rust from the surface. Dry the duct with a clean towel. Reapply more rust remover if any rust is remaining. Rinse and scrub using the same process for any additional coats of rust remover applied.

4. Prime the surface with a metal primer. Use a spray paint primer to easily reach all the areas of the duct. Hold the can about 8 inches from the surface and spray the area where you applied the rust remover. Let the primer dry for about 4 hours.

5. Paint the surface with a metal spray paint. Cover all the areas you previously primed with the paint. Let the paint dry for at least 4 hours.

6. Seal the leaking air duct. Apply aluminum foil tape over the leaking seams. Make sure the aluminum foil tape overlaps by at least 2 inches on both sides of the air duct seam. You can now turn on the air conditioner and check for any leaks. If you feel any air leak around the seams, keep covering it up with aluminum foil tape until no more air leaks are felt.

References

• Rust-Oleum: Rust Stripper