If you have a lawn mower that has rust holes in the deck, you don't have to replace the entire mower. Instead, you can clean and fill the rust holes and continue to use your mower for many more years to come. Rust that begins to eat into metal lawn mower decks will spread if not properly treated. Eventually, the deck may become too weak to support the engine, rendering the outdoor equipment unusable.
Put on work gloves and knock away as much rust from the lawn mower deck using a wire brush. Scrub the rust holes vigorously to get off as much rust as possible.
Abrade the rust holes on the lawn mower deck with medium-grit sandpaper to get more of the rust off the deck. Sand until the rust no longer comes off the lawn mower deck. Wipe down the rust holes with a tack cloth.
Liberally spray the lawn mower deck with engine degreaser and let soak as long as directed by the manufacturer. Wipe away the degreaser with a moistened tack cloth and let air dry.
Open the cold weld kit, and remove the epoxy resin and hardener. Combine the two ingredients together according to the manufacturer's proprietary mixing instructions. Typically, this is combining equals parts of epoxy resin and hardener.
Spread the mixture over the rust holes on the lawn mower deck and let cure for about 24 hours to finish.