Reviewers at both Amazon.com and HomeDepot.com rank Rust-Oleum as the best outdoor paint for metal surfaces, both in the brush-on and spray categories. Users award the brand four stars or higher, with top marks going to the Painter's Touch line and the Professional line.
Reviewers say that Rust-Oleum goes on easily and doesn't flake, chip or peel. Several users report that the fine mist helps to make a smooth finish, though multiple thin coats are recommended for the best results. The Rust-Oleum metallic metal paints are also popular, with reviewers praising the texture and sheen that gives the finish a naturalistic quality.
On Amazon.com, the brand Krylon takes second place for metal surface spray paint, particularly the Dual Paint and Primer line. Reviewers like the good coverage and smooth application that this line provides. They also appreciate the adjustable spray tip that reaches into tight corners.
Painter John Dee from the television show "This Old House" points out that surface prep and proper priming are just as important as choosing a quality paint. In his online Q&A "Repainting Metal Railings," he recommends cleaning the metal surface with a wire brush, then scuffing the existing finish with sandpaper for better adhesion. Wipe down the surface, then apply a rust-inhibitor to bare metal and rust spots before priming. Dee advises to use spray paint instead of brush-on for a smooth, even finish. Reviewers also like Rust-Oleum brand for outdoor metal primers, especially the rust-inhibiting line dubbed Stops Rust.