What Stops Existing Salt Corrosion on Aluminum?

Aluminum is a metal that is used for many household products, including deck and porch railings, light fixtures and outdoor furniture. Unlike steel, aluminum resists corrosion by moisture and air when exposed to the elements, but salt spray and road salts can cause a condition caused oxidation, which discolors the aluminum surface. A number of methods are used to stop the corroding effects of these salts.

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Salt spray can corrode the finish of aluminum furniture and railings.

About Aluminum

Aluminum is made from bauxite, a mineral that is mined from the earth. To make usable aluminum, bauxite is crushed and sprayed with water, and all traces of clay and silica are removed, according to the Elemental Container website. It is then processed and smelted into a material used for a wide range of products for both commercial and industrial applications. Aluminum has many applications because of its light weight, strength and corrosion resistance. It is also a good thermal and electrical conductor and can be worked into many shapes. These qualities make aluminum a metal that is used for many products for the home.

Salt Damage on Aluminum

All metals will corrode in the presence of salts. Though aluminum does not exhibit rusting like steel does, it will develop a chalky film and pitting in the metal surface when exposed to salt for long periods. A neutral soap and water wash will help remove the oxidized film. If the oxidation has built up for a long time, a buffing wheel will help remove it from the aluminum surface. To stop the corrosive effects, however, you must apply a protective coating to the aluminum and keep the coating maintained over time.

Protective Aluminum Coatings

To help protect the surface of patio furniture, lighting, railings, gates and other items made from aluminum in coastal environments and other areas where salt damage is common, protective paint coatings are generally used. Aluminum is a metal that does not hold paint well, however, so self-etching primers are frequently used to provide a good base for paint. Other types of coatings are available, as well, including powder coating, which applies pigment electrostatically to the surface along with a resin, according to the Powder Coating Institute website. This coating is then baked at high temperatures to give the aluminum a tough and attractive surface. Powder coating pigments come in a wide range of colors.

Preventing Salt Damage

To prevent corrosion of aluminum from salt conditions, inspect the material regularly and repair any damage to the surface coating as soon as possible. Rinse off the aluminum with plain water after exposure to salt or sea water. Avoid using acid cleaners on the aluminum and do not use abrasive compounds or materials that will scratch the protective coating. Damage to the coating will allow salt to penetrate the metal surface.