[time-nuts] DC distribution

[Malcolm Moore]

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.