I manufacture parts that require plating of a sandwich of copper between
aluminum, and I can assure you that it takes only minutes for the aluminum
adjacent to the copper to be attacked in a copper sulfate plating bath with
no imposed current flowing. It is essential to immerse the parts with the
plating current on in order to protect the aluminum from pitting. True, in
an aircraft you are unlikely to fly through an acidic solution but any
electrolyte will cause similar pitting, just more slowly.
I would suggest installing a disposable aluminum spacer between the copper
and the aluminum bracket, and to use stainless steel fasteners.
Best regards,
Rob Housman
A070
-----Original Message-----
From: owner-europa@post.aviators.net
Subject: Re: Bolting copper to aluminum
Alfred --
Copper is next to stainless steel on the galvanic chart, and we use SS
hardware on ali without concern. It would take many years for the
corrosion to insulate the ground plane, and the antenna would still
work almost as well through capacitive coupling. It just couldn't
handle high xmit currents, which ELT's don't have. I see no problem.
Regards,
Fred F.
Alfred Buess wrote:
>
> A simple question from a metallurgic ignorant to the experts out there:
> I have to bolt the copper ground plane mesh of my ELT antenna to the
aluminum bracket holding the antenna. Is there any risk of corrosion between
the copper of the mesh and the aluminum of the bracket? If yes, how can I
bolt it together, keep the joint conductive and prevent corrosion? Any
answer is appreciated!
>
> Alfred
> Monowheel #097
>
>
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