When your lawnmower starts spitting rusted or rotten pieces of metal, you know it's in need of repair. You can repair the mower deck by investigating the rust underneath the mower and applying a rust remover solution to do the job for you. It's much cheaper than bringing your mower in for repair or buying a new one, and you don't need to spend a lot of money to do it yourself.
Use a utility knife to scrape away as much rust as you can from the mower deck. You also can scrape away rust particles with sandpaper to make the metal surface smooth.
Put on protective gloves and goggles. Place your mower and rust remover in an area outside away from children and pets.
Rinse the rusted area with soap and water.
Follow the instructions specified for the rust remover's use. Some rust removers require you to spray or rub the rust remove onto the material and leave it for a few hours.
Rub the rust remover and the rust off the mower deck with a wire brush. This should remove the existing paint and rust in this area on the mower. Wait for about an hour before applying primer. This will give the rust remover enough time to disintegrate the existing paint and rust.
Apply paint primer to the mower deck and allow it to dry. Paint over the primer with your choice of paint. Painting over the area will offer protection and prevent further rust build-up.
Use a nontoxic and water-based rust remover solution from your local hardware store. Make sure it is one that can be used on metal.