Please can you advise which would be the best anti-corrosive primer to use on rusting metal balcony railings, ideally with a high-build finish to cover pitting? Thank you.
Providing you are able to remove the existing rust back down to a bare substrate then we would recommend applying 2-3 coats of Rust-Oleum Mathys Noxyde Peganox in one of the available standard colours. Peganox is a water based, low VOC, single component, elastomeric coating that provides rust-proofing, corrosion and waterproofing protection optimized for brush or roller application.