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No need to get all bent over sculpture rust

When a metal sculpture begins to show signs of rust, owners have several options to deal with it, including leaving the rust alone.
When a metal sculpture begins to show signs of rust, owners have several options to deal with it, including leaving the rust alone. Merced, Calif., Sun-Star file

Q: A Haitian wrought-iron sculpture has been hanging on our back porch for a few years and suffered consequences of the weather. Once black, it is covered with rust. The sharp edges make us wary of cleaning it ourselves. Is there a service that would restore it to its former rustic charm?

A: First you might want to consider whether it is really wrought iron.

Although the term often describes any kind of decorative ironwork, true wrought iron is shaped with heat and a hammer. A blacksmith heats the metal until it glows, a signal that the iron has become malleable. Then many swings of the hammer, or repeated pounding in a hydraulic forging press, gradually coax the metal into the desired shape.

It also is not welded or cut; instead, blacksmiths fuse joints by hammering them together and create openings by hammering the metal to the side.

Mark Bailey, who runs Metal Specialties (301-421-1832; metalspecialties.biz), a custom fabrication shop in Spencerville, Maryland, looked at the picture you sent and emailed to say he thinks the piece is not wrought iron: “This looks like a sheet of steel that has been plasma arc cut.”

Plasma arc cutters melt a thin line through metal using a narrow, focused stream of electrically ionized gas, or plasma. The cutter also blows the molten material to the side, creating separate pieces. Plasma cutting heats only a small path, so if the metal already is painted, most of the paint survives.

With wrought iron, any paint would burn off in the forge. (Iron shaped by either method can of course rust if left out in the weather without a protective finish.)

In the picture, the flat areas appear to have gray paint, which reinforces Bailey’s guess of how your piece was made. His reference to it as steel, rather than iron, isn’t all that significant for your purpose, since steel is just iron with a small percentage of carbon.

But if your piece was made by plasma arc cutting, it could affect the answer to your question about the best approach to refinishing the sculpture.

“There are a lot of answers, none of them the right answer,” Kirk Palmatier, a salesman at the Brass Knob Architectural Antiques in Washington (202-332-3370; thebrassknob.com), said after looking at the sculpture. It all depends on what you want.

“A lot of people like the rust look,” Palmatier said. It’s so popular that if a sculpture like yours were to show up at the Brass Knob, the shop would put it out for sale as is.

Preserving the existing finish, rust and all, would also preserve the remaining gray paint, which could be evidence that the artist in Haiti was improvising by using metal that had a former life as a gray part for some steel object, perhaps a car door. If you decide to keep the look, Palmatier suggested spraying the metal with flat lacquer to help keep the rust from getting worse. Or you could display the piece indoors.

But if you want the piece to look uniformly black, that’s also possible. Paint the sculpture or have it powder-coated, which will last longer. A shop that specializes in powder coating would sandblast the metal to remove the rust and any existing paint, spray on a dry paint powder that clings to the metal through an electrical charge, then put the sculpture in an oven so the finish bakes on.

Right A Way Powder Coating in Middletown, Maryland, (301-748-4362; rightawaypowdercoating.com) would charge about $50 for this.

If you want to tackle a paint job yourself, Bailey suggested taking off the rust with a product such as Rust-Oleum Rust Dissolver Spray ($9.97 for a 32-ounce bottle at Home Depot).

Wire-brush the piece first to remove loose rust and rinse off the debris with water. Wearing goggles and gloves, spray a liberal amount of the rust-remover onto the damp metal. Apply more, if needed, so the surface stays wet until the rust comes loose. This might take 10 to 30 minutes.

If some rust remains, repeat this process. Thoroughly rinse off the remains and wipe the surface dry. Don’t let it air-dry because a thin layer of rust might form.

After an hour, you can paint the piece, using either a spray paint or a brush-on formula labeled as suitable for use on metal. These paints typically bond best if you first brush or spray on a primer. Check the label.