If you love restoring old furniture, sooner or later you're likely to run into some kind of metal object whose surface needs refreshing. Many of these will be made from ferrous metals—iron or steel. With the exception of stainless steel, the primary element that begins their deterioration is rust, the oxidation of the surface brought on by exposure to air and moisture. Learn all about the causes of and solutions for rust below, then check out our top tips on how to paint iron and steel fixtures.
How to Get Rid of Rust
Rust can not only eat away at the metal and spoil its appearance, it can undermine any primers, paints, or other coatings applied to protect it.
Rust can start on bare metal more quickly than you might imagine—immediately when an unprotected surface is exposed to moisture in any form. Your objective, then, is to stop any rusting that has begun and to keep moisture and air from getting to the metal after painting. To prepare ferrous metals, you'll need to remove both the rust and any peeling paint.
On smaller jobs, use a scraper and a wire brush—the scraper to take off heavy rust and loose paint, the brush to remove the rust residue. On larger jobs, use power brushing and disk sanding with aluminum oxide paper.
These steps will leave the surface covered with small particles of rust and dust, which should be removed before you apply any coating. Brush them off with a soft-bristled brush, scrub the entire surface with a detergent-and-water solution, then rinse it thoroughly with clean water. Cleaning will also remove any mill oil (a residue from the manufacturing process), which can interfere with the paint bond. Prime the surface with a top-quality latex rust-inhibitive metal primer as soon as it dries. Brush or spray the primer at the recommended spread rate and apply a second coat to get the maximum resistance to corrosion.
Top-coat the metal with a high-quality acrylic latex paint. It can last as much as two to four times longer than conventional alkyd paints without serious cracking or fading.
How to Paint Iron and Steel
Prep: Remove all loose rust and paint using wire brushes, emery cloth, scrapers, cold chisels, and aluminum-oxide sandpaper as appropriate to reach all the contours of the material. Brush the resultant dust and rust particles off the surface with a soft brush and scrub the entire surface with a detergent-and-water solution. Rinse the surface thoroughly with clear water and let it dry. Then apply a coat of rust inhibitor, if compatible with your primer.
Prime: Brush, roll, or spray a high-quality latex corrosion-inhibitive primer on the surfaces you have repaired. Let the first coat dry and apply a second coat. If you spray or roll on the primer, back-brush it immediately, which will work the paint into the surface and create a better bond. Back-brushing the primer before it sets up will also remove any drips.
Paint: When the second coat has fully cured (see label instructions), apply two top coats of high-quality acrylic latex paint, allowing sufficient drying time between coats
Painting Ornamental Iron
Step 1: Remove Rust
Examine the surface thoroughly and remove loose rust as you come across it. Use new wire brushes of different sizes to get into as many of the small corners as possible. Where the brush won't fit, slide aluminum oxide sandpaper or strips of emery cloth to strip off the rust.
Step 2: Remove Paint
When removing loose paint from flat surfaces, use a chisel scraper or stiff putty knife. Chipped paint can be surprisingly stubborn. If necessary, remove it with a sharpened cold chisel and hammer, taking care not to dent or bend the material.
Step 3: Apply Primer
Using a top-quality latex rust-inhibiting primer, brush all surfaces from which you removed paint or rust. Work the brush into all the contours of the metal.
Step 4: Paint Two Coats
When the primer is dry, finish-coat the surface with two coats of a top-quality acrylic latex paint.
Step 1: Prep Cabinet
You can paint the cabinet with the drawers removed or leave the drawers in. Remove or mask off the handles and hardware. Then mask the interior sides of the drawer and spray paint the cabinet and edges of the drawer face. Apply a mist coat first, then several light coats.
Step 2: Paint
Paint the front face of the drawer. If masked, remove the tape from the hardware while the paint is still slightly wet. If you've removed the hardware, wait until the paint has dried completely, then reinstall the hardware.