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Anodising a 4 foot dia. Aluminium Ring

June 23, 2010

I have a project which requires the anodising of 6063 aluminium 4 ft washer ring 1/4 inch thick and 1.5" wide.
To reduce cost I have looked at buying an anodized bar and then roll it into shape and then welding it. The problem is the welded area is not anodized. The first question is are there any equivalent coatings I would apply to this weld section ?. The ring is exposed to the environment and is often used in marine conditions so the protection must be robust.
The standard process would be to roll the ring, weld and then anodize but I am finding it difficult to find a finisher supplier who can anodize 4 ft in size, any suggestions would be appreciated.

Cyril Stockil
Engineer - Albany, New York, USA

Hi, Cyril. I think I'd anodize after fabrication. This ring is by no means outsized. Architectural anodizing racks are sometimes 20 foot wide x 6 foot high. Even 40 foot wide is not unheard of.

You just need to look a little harder for an anodizing shop :-)

Regards,

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
June 23, 2010

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June 24, 2010

Anodize is aluminum oxide which is a ceramic and thus is brittle. If you roll it, you will have thousands of tiny cracks and probably some peeled spots.

If you do not want the weld to appear darker than the rest of the ring, you need to use the correct rod and it is not 6063.
Your anodizer may know what should be used, but you probably will have to ask another fab shop. There is a good possibility that you can get the answer by using the search engine at this site with the proper words.

James Watts
- Navarre, Florida