Powder coating originated in Australia in 1967. The technique coats metal with a thin, plastic coating that may have a glossy, matte or hammertone finish, which looks like the smith has textured the metal with a peen hammer. Powder coating comes in a wide range of hues. Because the craftsman fuses the material to the metal with intense electrostatic heat, the method works best with aluminum and steel.
Anodizing forms a thin coat of aluminum oxide on aluminum. Its hard quality protects the metal, but it adds color as well because the surface can be dyed a wide range of colors. The result is finished metal that's more scratch resistant and durable than untreated aluminum. All metal parts should be treated at the same time for a perfect color match. Anodizing works best on unbuffed aluminum that hasn't been cast or welded because the alteration changes the color in that area.
Electroplating commonly is used on brass, steel or copper. It adds a thin metal coating onto an electrically conductive piece. Finishes typically are made from nickel, silver, chrome or gold, with color choices ranging from black to chrome. This decorative finish is scratch-resistant. The craftsman must prepare the surface carefully, finishing it so that it has the same type of luster and detail as the coating. Powder coating provides an alternative to electroplating, if the metal is heat resistant enough.
Patination is perhaps the oldest type of decorative metal finishing. It involves chemically coloring pieces like jewelry and statuary pieces. The technique gives metal--usually bronze--color and a reflective texture to put carvings or texture in relief. Patina also works on steel. While patina or powder coating produces a more contemporary, sleek finish, patina focuses on an uneven, organic look. Different patina recipes create different effects. The basic "liver of sulfur" recipe produces a brown or black finish on bronze, converting the copper into copper sulfide. Proper cleaning of the metal surface is critical to patina properly adhering to the piece.