>--> Zenith-List message posted by: "tom tiedman" <ttiedman@hotmail.com>
>
>I'm wondering if a product like 'alnox' could be used between the electrical
>terminal and the aircraft structure to eliminate corrosion. We use it in
>electrical construction all the time where aluminum conductors terminate at
>lugs in various panels. It is a dark grey electrically conductive paste,
>that we spread all over the bare aluminum end of the conductor before
>inserting it into the lug (lugs may or may not be made of aluminum). It
>keeps the aluminum wire and the lugs from corroding. You could smear a dab
>of it on the side of the terminal that touches the aircraft structure and
>fasten down the terminal. Readily available at any electrical supply house
>worth its salt. I believe their is another brand of the same corrosion
>proofing paste known as 'noalox' available also if memory serves me
>correctly. Tom
It wouldn't hurt. Consider the following:
K
Ba
Sr
Ca
Na
Mg
A (Aluminum)
Mn
Z (Zinc)
Cr
Fe (Iron)
Cd (Cadmium)
Co
Ni (Nickle)
Sn (Tin)
Pb (Lead)
--H-- (Hydrogen)
Sb
As
Bi
Cu (Copper)
Hg (Mercury)
Ag (Silver)
Pd
Pt
Au (Gold)
This is a ranking of the elements in accordance with their
electromotive potential with respect to Hydrogen. The usefulness
of this table is to illustrate the tendency of two materials
to react in each other's presence while in metalic connection
(electrons can flow from one material to the other) and moisture
(atoms can become active in a liquid and combine with other
stuff - like oxygen and in essence rust).
The further apart the two materials are in the table
the more antagonistic they are to each other. Note that aluminum
is quite far removed from copper. Note further that tin is
between the two antagonists. By coating the copper terminals
with a layer of tin plating, the tin provides a buffer
between the aluminum and copper to mitigate their anti-social
tendencies.
"Noalox" and similar products provide some moisture barrier
in the vicinity of a dissimilar metals joint to reduce the
rate of corrosion.
A terminal bolted down to the airframe would probably benefit
from a variety of moisture barriers such as silicon grease,
Vasaline, Noalox or even a coat of paint. If you live in a
humid region of the country, especially coastal regions where
the moisture can contain salt, a little judicious moisture
proofing wouldn't hurt.
Bob . . .
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( The only time you don't fail is the last )
( time you try something, and it works. )
( One fails forward toward success. )
( C.F. Kettering )
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http://www.aeroelectric.com
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