On 5/10/19 8:17 AM, MLewis wrote:
With audio signals, a soldered crimp is one of the worst possible
connections. I wouldn't think it would be different for anything else,
but may go undetected until failure. If you've used the correct size
of crimp and used a proper crimping tool, then you've got the proper
pressure for a solid reliable connection. If you then solder, the heat
expands the crimp lessening the crimp pressure, and when it cools it's
no longer at the correct crimp pressure (often the wire will pull
right out), and with iffy wicking of solder. The worst of both methods
combined in one.
Where the wire is too thin for the crimp I have available, I've cut a
piece of a correct thickness wire/cable, inserted that into the crimp
along with the signal wire/cable, so it's crimped between them. I
don't know if that is the best way of handling that, but it's worked
for me.
On 04/10/2019 11:41 AM, John Ackermann. N8UR wrote:
West Mountain is a good source for all things PowerPole, but there
are a bunch of other vendors as well. And do youself a favor --
spend $30 on the three size 15/30/45 amp crimping tool. It saves
much aggravation. But if you're using thin wire, soldering after
crimping is a good precaution.
"If you then solder, the heat expands the crimp lessening the crimp
pressure, and when it cools it's no longer at the correct crimp pressure"
Usually crimp contacts are made of copper (PowerPole certainly are). The
wire is copper. If the crimped joint is heated for soldering, both
contact and wire will expand equally (they have the same coefficient of
expansion), so crimp pressure will remain constant.
Crimping was developed to allow fast reliable joints during production
using automation or lower skilled operators. Solder can produce very
reliable joints but is time consuming and needs skilled workers.
My experience during over 40 years of mainly repair & maintenance is
that crimping is fine when the correct tooling is available and both
contacts and wire are in as new condition (that is there must be no
tarnishing or discolouration, the first NASA link from jimlux gives that
as a reason for prohibition of contacts). In low volume or one off
situations such as the OP's request, where materials might be what's on
hand and tooling is the generic type, then flowing solder into the joint
is necessary for reliability. Heatshrink sleeving applied over the joint
and extending beyond where solder may have wicked to provides good
stress relief to prevent fracture. I've never had such a joint fail
after a repair, whereas the original crimp only joint had failed.
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