Great efforts are taken to prevent weather from affecting metal found on objects such as our cars. But once a weathered effect takes hold on other types of metals, it can become a feature, adding a distinguished patina that only time and the elements can form -- unless, of course, you fake it. Add antique looks to metal using paint without depending on Mother Nature.
Few statues come out of a mold with a finished look. Chemical patinas are added, then the high points that are most likely to wear are polished, removing the patina. This creates light and dark hues that give the exterior an aged look. However, chemical patinas can be harsh, expensive and limited to certain materials. Create the same effect with paint. Spray a light coat of semi-gloss black or burnt umber spray paint on a clean metal surface. Gently wipe away the paint, leaving some in the cracks and crevices. Use a cotton cloth or cheese cloth lightly dampened with paint thinner (or water for water-based spray paints.) Dab a little paint off high points on the surface. Let the paint start to dry slightly before polishing it gently with your dampened cloth.
You can paint wood or other materials with metallic spray paint for a metal appearance. For a more realistic look, find a subtle metallic paint because some paint called "metallic" actually have metallic-looking glitter in it. It won't resemble real metal. Spray several layers of primer on the surface of your material. The primer will help fill imperfections on materials such as wood grain that will detract from the illusion. Paint the piece with metallic paint after letting the primer dry. Use a couple of coats to avoid wearing through the paint and revealing the primer while wiping off the antiquing layer. Repeat the same technique on real metal by painting a layer of black or umber, then carefully wiping most of it away.
Metals from steel to copper are prone to oxidation. This is recognized by the color -- steel or iron-based metals rust, which is iron oxide. Other oxides seen in copper appear green. Whether painting a burnt-orange rust or copper-green, mix two or three different tones of the color. Make your first color match the predominant color of rust or aged-copper, then separately add a small amount of white paint to one portion and burnt umber or green to the other. Apply the lightest color first in the areas that look like they would be most likely to rust. Use a sponge for a paint brush, a fan brush or even dab paint with a moistened tissue. Follow up with the medium tone, then add a small amount of the darkest tone.
While aged metal, such as rust, takes on a velvety texture outdoors, the objects we use for decor get cleaned up when they're brought inside. Subsequently, metal antiques often have a lightly oiled or waxed sheen, similar to bronze. It might come from the oil left by hands touching the object, such as the way old doorknobs wear. Replicate this patina by applying furniture wax, then polishing it off, to produce a subtle luster.