[BC] Soldering D-sub Pins

[RichardBJohnson at comcast.net]

Well...."the rest of the story...." It used to be that every electrical
connection in aircraft was REQUIRED to be soldered. As aircraft
aged, the soldered connections failed and circuits opened up [2].

In the meantime AMP [1] (the inventor of the cold-welded crimp joint)
made and continually improved crimped connections. They became
so reliable that sometime in the seventies, their reliability outstripped
soldered connections. Nowadays, soldered connections are NOT
ALLOWED in aircraft, a complete turnabout.

Crimped connections need to be done properly. I see crimping-tools
that can't possibly create the proper cold-weld even though they have
a ratchet. A correct crimped connection is gas-tight, and actually
produces an inter-metallic bond, a weld.

Here is what NASA has to say.

http://snebulos.mit.edu/projects/reference/NASA-Generic/NASA-STD-8739-4.pdf


(1) In early motor building it was common to "AMP" the square wire that
comprised the field winding. AMP made a special tool, but didn't supply
any "connectors," which were simply pieces of copper tubing of the size
that would fit over the wire. The tool squeezed the pipe until it was 
completely
cold-welded around the wire. AMP meant "Aircraft and Marine Products."

[2] Solder will eventually evaporate, even at nominal room temperatures.
At elevated temperatures, the evaporation rate (sublimation) is quite rapid
and can cause solder to be lost on connections to power resistors and
other such components within 10,000 hours. Solder can also be corroded
by common aerosols such as ozone, salt-spray, and carbonic acid from
CO2 and moisture..

--
Cheers,
Richard B. Johnson