Ferrous metals need a finish more than wood does — without one, most quickly combine with oxygen to form rust that deteriorates or discolors them. Traditional smiths finish metal with wax or oil; when choosing oil, a drying oil, such as boiled linseed or tung oil, is a much better choice than raw linseed oil or mineral oil. It’s also a good idea to thin the oil before applying it and to heat the metal to improve penetrability. If you are just searching for a hand-rubbed finish on a non-ferrous metal, you can get one with spray paint or dipping substances.
OIl-Finishing Ferrous Metals
Prepare the metal by scraping off any previous finish that’s flaking or peeling, using a wire brush and scraper. Ideally, the alloy ought to be bare before you oil it. If the alloy has a preceding coat of lacquer, remove it by rubbing the metal down with rags soaked with generous amounts of lacquer thinner. Wear a respirator when dealing with lacquer thinner.
Make a finishing solution by combining boiled linseed oil with turpentine or mineral spirits at a 3-to-2 ratio. Add a dash of Japan drier, which aids the oil complete dry faster — a dash is actually the equivalent of about an ounce per quart of oil mixture.
Apply a thin coat of the oil mixture to the metal with a paintbrush. Allow it to dry to the touch; then rub off the excess with a clean rag. Repeat if necessary.
Allow the final coat to cure for several days to a week; then apply a coat of paste wax and buff it it to a shiny finish.