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Finishing to Inhibit Corrosion of Aluminum

 

I have a condition in which a client wishes to place an aluminum grating (alloy 6063-T5 in a fountain. Although the aluminum grating is not submerged, it is subject to water flow from jets in the fountain. The fountain jets are connected to a copper manifold. I have two primary concerns. If the fountain water is chlorinated, I am concerned about the potential for corrosion of the aluminum grating. I am also concerned about the possibility of water that has passed through the copper manifold running over the aluminum grating. I believe there could be some potential for the water to pick up enough copper to cause corrosion in the aluminum grating. Would clear anodizing the aluminum grating inhibit these potential corrosion problems. If not, would it be possible to apply a clear lacquer of some type to the aluminum grating to inhibit the potential corrosion problems?

Johnnie D. Hilburn Jr.
Wichita, Kansas United States

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Johnnie, is it possible to use a fiberglass grate? This would greatly simplify your problem.

If not, my suggestion would be to clean and pretreat the aluminum grate and then apply a clear powder coating. A chrome chromate based pretreatment would be my first choice as chrome is compatible with most powder coating systems. If a bright appearance is desired, use a low coating weight chromate. If chrome is not acceptable or available, then I would use the non chrome pretreat specified by the powder coating supplier.

Roy Nuss
Trevose, Pennsylvania, USA

I suggest that you use fiberglass grating, which has become very reasonable in price. We bought two grating panels (4'x12') for about $300 each from www.frpresource.com, and they are excellent choices for wet areas.

Mike Lane
metal finishing shop - Anaheim, California, USA