"Jeffrey D Angus" wrote in message
...
jakdedert wrote:
I'd be careful about using aluminum for this. You could set up a
situation
where over the years, the dissimilar metals would begin to react and
cause
all sorts of gremlins.

I could be wrong about this, but judging by the debacle during the 70's
where a lot of aluminum wiring got installed in a lot of homes--and
later
caused at least a few fires--I'd at least be cautious.

That was mostly hype stirred up by Jeraldo Riviera. Back when he
was still caucasion.

The real problem with aluminum wiring was three fold. 1. For a
given current ration, the aluminum wire has to be bigger than
copper. 2. Special terminations (screw and or compression type)
marked CuAl shoud be used along with a gel like "No-Ox" to protect
the connection 3. Proper torque on the fastenings is manditory.

Given the special requirements and the attitude of most workers
that "I know what I'm doing" of course it was a disaster.

I've also seen several places in my old houses where iron piping
was screwed directly into brass fittings. [ snip ] When finally
I got down to it, there was practically nothing of the threaded
end left, although the rest of the pipe was in good condition.

This is more the fault of the iron pipe. Not the bronze/brass
fittings. When you thread the end of a pipe, you remove the
galvanized coating. Exposed metal pipe = weak spot.

That might be the case if every iron pipe also exhibited this effect. The
only place I've found it was when an iron pipe was mated with a brass
fitting. A similar situation occurred in my kitchen wall, where the faucets
(mounted on the wall) were connected to the brass elbows nailed to the studs
with a short iron pipe. The ends of both pipes were corroded to hell within
the brass. I had to dig the rotton bits of iron out of the brass threads
(not as difficult as it sounds, the iron was completely oxidised and
crumbling) without damaging the brass. Otherwise, I'd have to had opened up
the wall to replace the elbows. Just a few years later, when the kitchen
was remodeled and a more conventional sink installed, the replacement pipes
were already noticably corroded. Any time two dissimilar metals are placed
in contact with each other, galvanic action occurs. Given a bit of
moisture, corrosion occurs; thus the No-Ox paste for copper to aluminum
terminals.

A Galvanic chart appears on this manufacturers website:
http://www.katonet.com/Techinfo/News...may-jun-00.htm

jak

Jeff



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safety deserve neither liberty nor safety." Benjamin Franklin
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Tara Morice as Fran, from the movie "Strictly Ballroom"