A century ago, aluminum was considered a precious metal, more precious than gold or silver. Only a very small amount of the metal had ever been isolated. At the start of the twentieth century, it had never been used before in architecture. By the century's end, its usage in architecture has overtaken just about every other metal.
The lightest of the commonly used architectural metals, it is also porous. Like galvanized steel, aluminum will develop corrosion pockets over time which will eventually deteriorate the metal's integrity. Painted aluminum is one way of protecting aluminum, but it is not without its costs and downsides. Painted aluminum adds severals steps to the process of finishing a metal surface.
Fluorcarbon Coatings for Aluminum
In 1938, Teflon was developed by the DuPont Company. Teflon was the name given to a very inert compound, called a fluorocarbon. Later, this incredible resin was modified to develop various fluorocarbon paint finishes, most notably the Kynar 5000 coating whose baked-on finish is among the most enduring coatings for aluminum.
Baked-on finishes such as KYNAR 5000 and urethanes are excellent coatings for exterior aluminum. Depending on the quality of the finish, painted aluminum can last up to 20 years, after which it will begin to incur continual maintenance costs for the client as repeated coatings become necessary. Field-applied coatings will not be as effective as factory-applied coatings, which creates a negative cycle of maintenance for the client.
Protecting Aluminum from the Elements
When using aluminum, care should be taken to ensure that it is not in a high-traffic area, where it would be scratched. and that it also not be used in areas where common pollutants will degrade its surface.
There are several ways to protect aluminum and slow the effects of pollutants. Proper detailing will slow the effects of pollutants, and in rural environments, corrosion moves at a slower rate.