Hose down your aluminum railing with a hose. Pour some detergent into a bucket of water until the water becomes sudsy. Scrub down the railing with a sponge dipped in the bucket.
Rinse off the railing again. Allow the railing to completely dry in the sun.
Use a tack cloth to wipe the entire railing. A tack cloth will help the paint primer stick to the railing.
Place drop cloths (or tarps) on the surface of the pontoon near the railing. The cloths will protect the boat from paint that splatters.
Brush an aluminum oxide primer on the railing with a paint brush. Give time for the primer to dry.
Brush on a marine water-resistant, oil-based paint to the railing within two days of applying the primer.
Allow the railing to dry. Add a second coat of paint if necessary.
