Alodine Resistance?

[szicree]

Can anybody tell me if a alodined aluminum is an okay conductor?

[DGlaeser]

Everything I've ever read says to clean the surface down to bare aluminum for electrical contacts. Alodine oxydized the surface, and I believe that coating is a poor conductor.
I've put some local grounds (wingtip lights, landing lights) on the spar near the wingtip. After cleaning and mounting the connection, I coated it with Goop for protection.

[mlw450802]

Originally Posted by szicree

Can anybody tell me if a alodined aluminum is an okay conductor?

That's a good question. I know that anodized aluminum is pretty lousy. I have several loose alodined parts at home and I'll check to see later.
-mike

[mlw450802]

Originally Posted by szicree

Can anybody tell me if a alodined aluminum is an okay conductor?

OK, I just put away the DMM and it would appear that the alodine surface is non conductive but quite thin. Light pressure from the probes showed an open circuit but increasing the pressure slightly would push through and show conductivity. The darker the alodine, the more pressure seemed to be required to break through.
This was just qualitative science here- no actual force measurements.

The anodized spar, however, was an insulator regardless of probe pressure.

-mike

[RV8RIVETER]

Originally Posted by szicree

Can anybody tell me if a alodined aluminum is an okay conductor?

Yes, Alodine converted aluminium is conductive. It does not oxidize in a true sense,(which anodizing does) but a chromate conversion process of growing a chromate oxide on the base metal. This chromic oxide layer is conductive.

Of course I am talking about the typical Alodine that has been in use for some time. The newer Alodine formulations, 5700, 2600 ect are chromium free.These newer ones, I do not know.

For more, less technical info:
http://www.eaa1000.av.org/technicl/c...on/alodine.htm