> you must remember...
> Solder is NOT designed to be the electrical connection.
> It is designed to hold the mechanical connection
> in place.
That is exactly backwards ! Soft solder (as used in electrical connections)
is _not_ designed to be the mechanical connection, it is only to make a good
electrical connection. Any decent course in wiring will teach you to make
the mechanical connection first, and only then add solder.
Yes, solder is a slightly poorer conductor of electricity than copper. The
ideal situation would be no connections at all. Since we have to make
connections, solder is an excellent second choice. The resistance of the
solder is a very minor issue, since the current flows through it for only a
very short distance, and spread over a wider area than the wire. The main
concern is to get a gas-tight joint, since copper exposed to oxygen in the
air will eventually turn into copper oxide, which is a lousy conductor.
Note that most crimp connectors are coated with what is essentially solder,
to help them form a gas-tight joint with the copper. The difficulty in
judging whether a gas-tight joint has been made is my main objection to
using crimp only. Best is still a combination, as I suggested.
BTW, I used to work for a company that did special-purpose mini-computer
installations aboard seismic survey ships. Worst environment for
electronics that I can imagine. Salt air, temperature extremes, and a keg
of dynamite going off under the stern every 5-10 seconds for days on end.
We used a mixture of soldered and crimped joints (even some wire-wrap), the
soldered was more reliable by probably a factor of 2 (with crimped trailing
even wire-wrap). Mind, these joints were made by trained technicians, using
carefully calibrated crimp tools and controlled temperature soldering irons,
so your mileage may definitely vary.
Randall
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