Wrought iron is a robust and malleable black substance made from an alloy of iron, carbon and silicon. Cast-iron fences can rust due to oxidation from the environment and humidity, resulting in corrosion and an unpleasant look. With the proper technique, you are able to clean, prime and paint a rusted cast-iron fence to restore its appearance and protect against future oxidation. Utilize primer and paint designed specifically for metal for the very best results.
Eliminate rust from the ironwork. For small rust stains, use a handheld rotary tool fitted with either a stainless steel or abrasive brush attachment. For midsize rust stains, match a aluminum oxide grinding wheel attachment to your rotary tool rather. For large rust removal tasks, use a power sander.
Dampen a cloth with mineral spirits and wipe the fence to eliminate as much debris as possible.
Paint the cast-iron fence with a rusty-metal primer. Use smooth strokes with a paintbrush and cover the iron completely. Permit the primer to dry completely.
Paint the cast-iron fence with two coats of metal paint. Use thin, even coats. Permit the paint to dry completely before applying the second coat. If you use spray paint, it may take up to four coatings for full coverage.