Although most any type of paint will appear to cover rust upon application, the rust will eventually reappear unless it is properly sealed. Unfortunately, no paint will permanently cover rust unless a specific type of primer is applied, first. Unfortunately, not all paints are compatible with this type of undercoating. Once the rust is treated, only specific types of paint should be used.
Iron oxide primers are appropriate for covering rust. Ordinary acrylic and latex primers may appear to cover rust, however, they will not prevent the rust from returning. Once the rust is covered with an iron oxide primer, it is ready for paint.
Oil-based enamels are appropriate for finishing primed, rusted surfaces. Oil-based enamels are extremely durable and provide an attractive gloss. Acrylic latex paints will not adhere to oil-based iron oxide primers. Water-based acrylic paints should not be used to coat surfaces primed with oil-based coatings. They will peel rapidly after application.
Acrylic latex paint
Acrylic latex paints are appropriate for finishing rusted surfaces if they are coated with water-based, latex iron oxide primers. These type of iron oxide primers are relatively new and are easier to apply than oil-based iron oxide primers. Oil based enamels should not be applied on top of water-based iron oxide primers. Acrylic latex paint is not as durable as enamel paint. However, it is less messy and easier to apply.
Epoxy paints are ideal for those who wish to avoid oil-based coatings. Epoxy offers similar durability as enamel, but is less messy and easier to apply. Epoxy coatings are appropriate for covering rusted surfaces, coated with latex iron oxide primers. It should not be applied over oil-based iron oxide primers.