Fergkyle wrote:
>
> Cheers,
> Like earlier may I suggest a gander at aeroelectric.com? Bob
> Nuckols has a special tool and short course, plus elsewhere he states why we
> should avoid solder in favour of crimping. It's gripping.
> Ferg A064
But, Ferg, he's the same Bob Nuckolls who describes soldering D-sub
connectors and even #2 or #4 wire, large ring terminals. The latter I
think is questionable, but only due to the difficulty of getting
enough heat, fast enough, on the thing to ensure good solder flow
without making an ugly mess.
Re crimping AMP connector pins he discusses, the devil's in the
details. The tool sure looks cheaper-made the Molex "prototype"
cheapie. It appears to just wrap the tangs around the insulation,
which isn't that strong. It's OK for in-flight integrity, but he
doesn't describe subjecting it to a pull test, about 30 pounds at
these gauges, which is important for inline connectors periodically
disconnected. Again, the proper tool will "shark" bite into the
insulation, and even the Molex cheapie does pretty well on .093" pins,
but not the little ones. Another factor is that on the small pins,
larger gauge wire doesn't crimp well at the wire strands, don't care
what tool, so pull strength is further reduced. A good solder
connection will very simply not pull apart.
I didn't find his opinion on solder v. crimping the small ring
connectors (except his citing general misconceptions in the
big-terminal article). I have a Sept. '93 article in EAA
Experimenter, "To Crimp or not to Crimp," which cites numerous civil
and military technical documents. The problem is not the soldering
itself, but builders who buy solder at the hardware store not knowing
it may require flux, or use a big metalsmith's iron or the big
electric guns. And can't spot a cold solder joint. True the author
says even of some FAA-certificated mechanics, and _that's_ why FAA
politely but specifically oppose soldering. It's true also that the
cheap crimpers just mash the terminal flat, looks unprofessional, and
often won't pass the pull test. To me all this says learn to solder
properly or buy the expensive tool, but no in between.
Perhaps Mr. Nuckolls is so good at what he does he hasn't had many
in-service failures, unlike me or any others similarly ham-fisted.
I'll bet most airframe/powerplant mechanics will confirm that no solid
connection, with proper wire dressing, will come undone behind an
instrument panel. Up in the shaky engine room, yes, soldered or
crimped. If not routed/tied properly, it's just a matter of when.
Regards,
Fred F., A063
|