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Ground lugs on Alodined parts

I need to ground several elements of an electromechanical assembly. The elements are aluminum and either Alodined or anodized. Can I use a flat ring lug bolted directly to the Alodined parts, or will tightening the steel bolt cause the ring lug to twist, thus scraping off the Alodine and allowing aluminum oxide to form? How conductive is Alodine?

John Salisbury
- Sunnyvale, California
2001

Dear Sir,

The Alodine coating is not designed for wear resistance. If it does twist it will surely "break" through the coating. If the parts are anodized, then you will not receive a good ground due to the inherent resistivity of the coating. One option that you may look into: Try applying electroless nickel over the areas where you plan to ground. This provides corrosion resistance of the aluminum and will provide the wear resistance you seek.

Best of Luck.

Ira Donovan, M.S.F.
Kansas City, Missouri
2001