A Blacksmith Shows How to Protect Ornamental Metalwork
The fight against corrosion never ends, but it can at least be reduced to an occasional skirmish.
For use outdoors, iron is hard to beat. Cast or wrought, the malleable metal is strong, nontoxic, doesn't burn or rot, and is impervious to insects. No wonder it's long been a favorite for railings, fences, planters, benches, and gates, to name just a few.
There's only one problem: When exposed to moisture, iron — along with its close cousin steel — rusts. Given enough time, every bit of the hard metal will dissolve into red dust.
The fight against corrosion never ends, but it can at least be reduced to an occasional skirmish. One veteran of the rust wars is Bob Bernard, a blacksmith in Savannah, Georgia, who keeps busy rescuing the ornamental metalwork that abounds in his city. He has no end of customers. "The air here is saturated with salt and humidity," he says. "On some days, you can literally watch the rust form on bare metal."
On the next page, Bernard shows how to get an old wrought-iron gate looking like new, a project that took just four hours over two days. To keep it fresh, go back once a year to touch up any dings with some primer and paint. Then every five years, he says, sand it and put on a fresh coat: "Keep the coating intact, and the iron will last indefinitely."
Fresh Finish In 5 Steps
Rub a steel-bristled wire brush over all metal surfaces to get rid of loose paint, flaking metal, and powdery rust.
On flat surfaces, use a mill bastard (coarse) file or a scraper to grind rough patches of rust down to bare metal. On rounded surfaces, 80-grit sandpaper does the trick. Wipe down the surface with mineral spirits.
Spray all exposed metal with phosphoric acid, which converts any rust you've missed or can't reach into a black, inert crust of iron phosphate. Bernard uses a product called Ospho. Be sure to protect your eyes, skin, and lungs from the spray.
Wait a day for the acid to penetrate and react fully with any rust, then brush away any loose flakes. Apply a thick base coat of oil-based metal primer using a disposable bristle brush (aka "chip" brush).
Let the primer dry before putting on the finish coat with a new chip brush. For maximum durability, choose an oil-based metal paint, preferably one made by the same company. Black is the traditional color for ironwork; a glossy sheen lasts longer than a flat one.
To give wrought iron a smooth painted coating, it helps to follow a methodical painting sequence that moves from top to bottom, as shown in the photo below:
1. Upper bars
Using a series of quick brush strokes up from the top rail, paint each bar all the way around. Where a bar is topped with a finial, paint the finial first, then halfway down the bar, then up from the rail.
2. Upper rail
Brush out from each bar's base until the paint film is continuous. Paint the rail's underside around each bar in the same fashion.
3. Middle bars
Paint each bar completely before moving to the next. Brush with downward strokes all around and most of the way down each bar. Then paint up from the bottom rail.
4. Bottom rail
Follow the same sequence as the upper rail.
5. Bottom bars
Brush each one down from the bottom rail. —Thomas Baker
On wrought ironwork with intricate scrolls, coat the crevices where a brush can't reach with spray paint. Apply light coats (to avoid drips), and immediately brush out any overspray. Finish all the spray painting before brush — painting the rest of the work.