All common metals are processed with oxides to bring them to a usable state. From the moment processing is complete, nature slowly goes to work to convert metals back to their original form. This corrosion exacts a costly toll around every home.
Not only is corrosion unsightly, appearing as rust on iron and steel, or tarnish on more precious metals, it can be dangerous. A crack in an auto floor caused by corrosion could lead to carbon monoxide poisoning. Failure of a metal ground-wire camp in an electrical system could cause a serious short or shock. Steel fasteners on a ladder could cause a fall if they've rotted from continuous exposure to the elements.
Other places to look for rust and corrosion to prevent possible danger are pipes and fittings around a gas meter, guard rail fasteners, furnace exhaust ducts, TV antenna masts and fasteners, outdoor electrical conduits and children's play equipment. Discoloration of a metal is the chief symptom that corrosion is occurring.
The best way to prevent corrosion is to seal metal objects against the corrosive environment with paints, varnishes or lacquers, inhibitors, greases, oils and waxes. There are many good paints available, some with rust inhibotors that give excellent resistance to decay. As with all paint jobs, preparation and application of a suitable primer are most important. Painting over loose rust won't work.
To prepare a metal surface for painting, scrape, wire brush or sand to remove any loose scale and rust as well as loose paint. Select a suitable primer for the surface to be painted, and for its condition. For example, Rust-Oleum 769 Damp Proof Red Primer is recommended for badly rusted metal. For clean or only slightly rusted metal, Rust-Oleum's 960 does the trick. While some products claim one-coat rust prevention, for lasting results, use three steps: prepare the surface, prime, and finish with a compatible topcoat.
Clear lacquers and varnishes protect metal without hiding the original finish. Copper and brass can be polished to like-new condition and kept looking that way by spraying on a clear finish. Or, if an object has tarnished to an appealing stage, the process can be arrested with the application of a clear varnish or lacquer. The dull, whitish film that develops on aluminum can be removed by cleaning, and the clean surface can be protected with a clear coating.
Inhibitors are chemicals that can be introduced to make an environment less corrosive. Moisture-displacing sprays such as WD-40 are useful for protecting bare metal objects such as tools and machine surfaces, which cannot be painted. The most familiar use of inhibitors is in the cooling systems of cars. Most anti-freezes contain inhibitors, but, in time, replenishment is necessary. Du Pont's Anti Rust is available for this purpose.
Silica gel pellets are another type of inhibitor. A bag of them inside a toolbox or drawer will absorb moisture to protect the contents from corrosion.
Rust, tarnish and other forms of corrorsion can be removed with chemical preparations provided the object hasn't decayed past the point of being basically sound. There are many good preparations on the market. Those for removing rust are generally acid preparations suspended in jelly. It is usually more effective to go beyond the directions commonly found on labels which instruct the user simply to brush the substance on the corroded areas. It works better to find or make a shallow trough and soak the object in the chemical solution. Occasional sanding with wet-or -ry abrasive paper during the soaking process will speed rust removal.
Several homemade preparations for removing corrosion are listed in the National Bureau of Standards' Consumer's Guide on corrosion, published by the U.S. Department of Commerce.
