Steel core elements

Roy Lewallen makes a good point about the use of plated steel for feeds
and/or elements.

On a practical side, some of you may recall that some time back I launched
a query concerning the magnetic permeability of stainless steel. This
query floated out of problems we experience in this country with the theft
of copper wire. Turns out that while you may be willing to live with the
ohmic losses of the stainless steel, if it has a reasonable magnetic
permeability as well, you should think again. I considered galvanized
wire, but the coating is too thin, and the Mu is too high.

I don't know what the position is in other countries, but here one can get
two types of wire, one clad with a substantial coating of copper,
Copperweld, the other with aluminum, Alumoweld. Now comes some
practicallity. I have seen damaged copperweld wire where rust spread down
the inside steel core through a surface nick, thus destroying structural
integrity. I have not seen anything similar on alumoweld. I do not have
the electrochemical tables handy, but would guess the potentials are such
that it is self annealing - like good galvanizing.

One can also get stranded aluminum wire wrapped around a central steel
core (Trade name Cedar wire?). This works very well.

A word of caution if you are planning to use aluminum. Get some new tools.
 I have heard unconfirmed horror stories of aluminum wire being used at
the coast, and dropping off pretty smartly. Apparently the copper
residues on the tools used did the dirty work of accelerating electrolytic
action.

Have a great day regardless. Duncan Baker.
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Received on Wed Feb 07 1996 - 06:39:00 EST