Well Randall...what differs in your statement from what I said.
You are suppose to have a good mechanical connection
and then solder it to hold it that way. So my statement is
not backwards.
I spent 12+ years designing submarine navigational systems
and Passive Towed Array Sonar for the U.S. Navy
Later systems went to hybrid micro-circuits which forced
me into Mil Spec 2000 work in a clean room environment.
We spent nearly two weeks of class time just studying the molecular
structure and fault modes of solder joints. The IEEE Institute
even has a 1200+ page manual available just on this subject.
Solder 'in electrical circuits' is used to hold it in place.
IT IS NOT meant to BE the electrical connection.
If anyone believes otherwise...lets' just see if you can
get anything manufactured and sold to the military or
aerospace to mil spec 2000.
You even said it yourself. You use to solder your wire-wrap
connections. That was 'in effect' for the longevity of the connection
Not just electrical connectivity ...but to stop the atmospheric
effects from corroding the electrical connection made
by the MECHANICAL CONNECTION process of wrapping
the wire around those little posts.
So I stand by my statement. Any good connection must first be a good
clean mechanical connection. Then solder it to keep it that way.
the solder is not meant to be the electrical connection, just keep the
'proper' mechanical connection together.
Paul Tegler ptegler@gouldfo.com
----- Original Message -----
From: "Randall Young" <ryoung@NAVCOMTECH.COM>
To: <triumphs@autox.team.net>
Sent: Wednesday, January 23, 2002 2:50 PM
Subject: RE: Bullet Connectors
> 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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