To remove rust on a metal such as wrought iron, knock off as much as possible with a wire brush or with a brush attachment on an electric drill. Then sand down to bare metal with medium-grit silicon carbide paper, using an orbital sander on flat surfaces. Finish with fine paper or steel wool. Before painting, clean the surface with paint thinner and apply a rust-resistant zinc chromate primer.
On small tools or other surfaces that are hard to sand, brush off as much rush as you can. Then apply a gel-like rust remover as directed.
On a large job, you can lessen your work by applying a rust converter-a primer that turns solid rust into a protective coating. First, brush off loose material: then apply primer with an old paintbrush. Let it cure as directed before painting.
On siding stained by nailheads, use sandpaper or steel wool to remove as much rust and stain as possible. Sink each nail with a nail set and fill the hole with putty or spackling compound. Then prime the spots with a latex or shellac-based stain killer. Put two coats over flathead nails which can’t be countersunk. Coat a stain on an interior wall with an alcohol-based primer; repeat if it bleeds through. Scrub a rust stain on concrete with a mix of 1 part muriatic acid to 9 parts water.
To prevent rust use only rustproof aluminum, stainless steel, or galvanized nails and screws in areas exposed to moisture. Put a rust-resistant primer on any exposed metal piece: prime and paint its hidden sides before installation. Rub a few drops of light oil on hand tools, saw blades, and bits that you store in a damp basement or garage. Use a wax or silicon spray on stationary power tools’ work surfaces.