While fiberglass can form a protective barrier over metal surfaces, it is not typically used to repair rusted metal. The main issue is that fiberglass is only effective at protecting metal from future corrosion if the metal is properly prepared before application. Rusted metal needs to be thoroughly cleaned and treated to remove any remaining rust and ensure a sound bonding surface for the fiberglass. Failure to do so will result in the fiberglass eventually delaminating from the metal, and the underlying rust will continue to spread, compromising the integrity of the material.
Fiberglass is more commonly used to repair non-metallic materials, such as fiberglass boats or panels. It can also be used as a reinforcement material for structural repairs in certain situations, but it is not ideal for repairing rusted metal. For metal repairs, more suitable options include welding, metal patches, or chemical rust removers and protective coatings specifically formulated for metal surfaces.
