From: dingbat@codesmiths.com (Andy Dingley)
Newsgroups: rec.autos.4x4
Subject: Re: Off road lights-How to wire ?
Date: Sat, 08 Mar 1997 11:56:08 GMT

The moving finger of Jerry Bransford <jerryb@cts.comnospam> having
written:

>Absolutely not.  No one in the electrical/electronic industry (where I
>spent 27 years) who knows anything at all would *ever* say a crimp
>connector is better than soldering the connection.  

Strange, try asking someone in the telephone industry.  Jelly or
grease-filled crimps have been universal on U/G plant for twenty years
now.   

In a previous incarnation (the incarnation after being a telephone
engineer) I used to write software for QA on press machines that made
crimp connectors, and machines that assembled crimp connectors onto
cable looms. The MTBF on a factory crimp is far better than that on a
solder joint, in a typical automotive context. When soldered joints
fail they nearly all do it through a brittle fracture due to
insufficient stress relief. Mil-spec bayonet multipoles are all very
well, but they need a rubber sleeve over every solder bucket at the
back if they're not to fail from vibration. Car-type connectors don't
have this luxury.  NB - heatshrink won't stress relieve a cable going
into a solder bucket either - you need the elasticity of rubber if
it's going to be reliable, polyolefins are too stiff when shrunk.

You also mentioned aluminium cable. Apart from aluminium cable being a
really bad idea for anything except multi-kV utility grids, how on
earth are you going to solder that ?

Home-made crimps can be reliable, but you need a good ratchet crimp
tool (maybe $50), crimps that are appropriate to the wire gauge you're
using, crimps that are made of unplated brass (less corrosion trouble
in the future) and good wire stripping technique. Don't twist the wire
before you crimp it - you want the strands parallel and without errant
whiskers. Don't use the pre-insulated crimps (red or blue plastic
sleeves) either - you can't control the crimp force if you're
squishing a plastic doughnut.

The second-worst connector is a soldered crimp. It's no longer a
gas-tight crimp, and it's a bad stress-relief for a solder joint.

(The worst is of course a Lucas bullet)

--
Smert' Spamionem