Rivets leak because wear and tear eventually loosens them, causing gaps where water can get through.
There are a couple of ways to find leaking rivets. The first way is to fill the boat with water (easier to do while it's on the trailer), or fill it part way with water, and use a marker to circle any rivets that leak. If you don't want to fill the boat with water or it's the middle of winter and you can't fill the boat with water, an alternative is to use a small suction cup-type dent puller. Place it over a rivet, and pull a vacuum with it. If the rivet holds the vacuum seal, it's good; if it doesn't hold the seal, it will leak. Circle any bad rivets.
When the boat is dry and clean, repair leaking rivets with an epoxy-based sealer such as West System G/Flex 650-K Aluminum Boat Repair Kit, TotalBoat FlexEpox, or TotalBoat Aluminum Boat Leak Sealer, according to the manufacturer's directions.
|West System G/Flex 650-K
For either of these epoxy products, you can use a wire brush to expose bright metal around the rivet. Mix the resin and hardener components, as directed, and transfer it to a plastic epoxy syringe. Heat the rivet with a heat gun or propane torch to remove any remaining water. Use the filled syringe to apply the epoxy around the head of the rivet.
After filling the rivet, heat it with a heat gun to help the epoxy penetrate completely and set quickly.
TotalBoat Aluminum Boat Leak Sealer: Use 80-grit sandpaper to sand within a 1" radius of the rivet head until the metal is bright and shiny. Attach a static mixing tip to the Aluminum Boat Leak Sealer cartridge and insert the cartridge into a caulk gun. Apply a bead of Aluminum Boat Leak Sealer around the rivet head to form a flexible, waterproof seal.