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Anodize aluminum boats

We are a small manufacturer of small aluminum boats and we are trying to find how feasible it would be to add color anodizing to our services. Welcome any info as to whether we should try to set up our own anodizing process or shop it out.

Thanking you in advance

Milton DeMars
- Killian, Louisiana
2000

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April 2, 2009

Hi, Milton. As a brief intro to the steps involved, after mechanical polishing and buffing you need to:

Caustic clean, rinse, caustic etch, rinse, desmut, rinse, anodize, rinse, dye, rinse, seal, rinse. So the process line would have to include at least 12 open-top tanks large enough to accommodate however many boats you want to anodize simultaneously. However, many of these rinse tanks should be double or triple. Figure an hour in the anodize tank, half an hour in the seal, and less than 5 minutes in the other tanks. The anodize tank requires a rectifier sized for say 24 volts and 25 Amps per square foot of surface area.

Although aluminum is rarely regulated in wastewater, aluminum alloys contain metal such as copper which will be.

You can learn more about anodizing in Robert Probert's "Aluminum How-To" or in Surface Finishing and Treatment of Aluminum and its Alloys by Wernick, Pinner & Sheasby.

Please recognize that neither many of the major appliance makers nor any of the auto makers do in-house anodizing anymore, like they used to, for environmental and other reasons. If you have a powerful need to control the anodizing process, it can be done in house. But don't think about doing it in-house for economy because you will find additional cost rather than savings. Good luck.

Regards,

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey