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Q&As since 1989


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Anodizing Finish

 

I am restoring an old Mercedes 190SL and thus far have been able do 99% of the work myself, however, I am having difficulty with anodizing the aluminum trim parts. After removing the dents, sanding, and polishing to a mirror finish, anodizing (after sealing) leaves a cloudy surface on my test parts thus far. The original pieces have a near chrome like finish, however, they are not plated. Is there a dye that will impart this bright surface? I am using a sulfuric bath, have tried from 10 to 30 minutes, and try to stay near 10 amp/sq ft although my power supply drops to about 10 volts at this current.

Thanks in advance for any suggestions.

Walter Puryear
- Athens, GA, USA

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I guess I'd suggest that you try to do 98% of the work yourself, and send these parts out to an anodizing shop that has bright dipping capability. It involves a truly noxious mixture of phosphoric and nitric acid that cannot be done at home.

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

Up to 99.5% now as the problem was found in the sealing water. Have a little faith.

Walt Puryear
- Athens, Georgia
 

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Glad to hear it. You can steam seal the parts if you can't keep the water clean enough, but indeed you must seal them well or they will absorb soils.

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