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PostPosted: June 10th, 2020, 11:15 pm 
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tomp wrote:
You realize how much better crimp connections are when you work with 500 MCM wire carrying 400 amps. Even the slightest resistance results in a very hot connection. Soldering just will not do. Soldering basically takes a lower current connection that has been properly made mechanically and seals it from the environment. It should never be a substitute for a good mechanical connection.


I have a box with various power cables for a smaller, three-phase UPS sitting at home. None are soldered.


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PostPosted: June 10th, 2020, 11:17 pm 
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When I was performing design/build of computer data centers the raised floor and system grounds, and power feeds had to be much more reliable than compression connections provided. Mission-critical and broadcast systems had to be CAD-welded. Including radio/TV tower ring grounds.

CAD-Weld is a brand name for exothermic welding, also known as exothermic bonding, thermite welding, and thermit welding. It is a welding process that employs molten metal to permanently join the conductors. The process employs an exothermic reaction of a thermite composition to heat the metal, and requires no external source of heat or current.

In terms of audio interconnects -- I went over to dark side at one point and loomed my system with Audioquest cables. Coffee, Fire, WEL Signature cables that had cold-welded connections and battery-bias on the dielectric. I had an idea for my own interconnects made from dead scratch. Not re-terminated mil-spec or industrial stuff but from scratch -- including the conductors, dielectric, and jackets and terminated with 37/63 Eutectic solder. It started out as an experiment, but turned out so well that I sold off my hi-end stuff. It just never lived up to to the science hype. I even tried the Stealth cable made with very thin Electum (a gold/silver alloy that occurs naturally) conductors suspended in a Teflon matrix. They did not make the final cut either. I made a .5-meter AES/EBU digital interconnect, a .75-meter analog interconnect -- DAC to per-amp, and a 1-meter analog interconnect -- pre-amp to power amps. They were a royal pain-in-ass to fabricate, but well worth the effort.

Anything can work well if properly executed. I once worked with a tech that came to us (SHL Systemhouse) from General Electric Aerospace. Before he could be certified to work on their stuff he had to attend an in-house course for soldering. A 6-week, 5-days per week studying nothing but soldering. Soldering is not as simple as some believe.

DIY ROCKS! :thumbup: Soldering ROCKS! :thumbup:


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PostPosted: June 11th, 2020, 7:02 am 
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SoundMods wrote:
tomp wrote:
You realize how much better crimp connections are when you work with 500 MCM wire carrying 400 amps. Even the slightest resistance results in a very hot connection. Soldering just will not do. Soldering basically takes a lower current connection that has been properly made mechanically and seals it from the environment. It should never be a substitute for a good mechanical connection.


You keep yacking about 500 MCM wire. Who in the hell among the many DIYs are going to hook up their systems with one-inch diameter cable? :crazy:


I believe Tom was making a point about the electrical efficiency of the connection, not the size wire.

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PostPosted: June 11th, 2020, 7:38 am 
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I believe Tom was making a point about the electrical efficiency of the connection, not the size wire.[/quote]

I got that -- but the comparison could have been made referencing audio stuff and Sta-Kon crimp connections. Here is the link:

http://www.tnb.com/pub/en/brands/sta-kon

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PostPosted: June 11th, 2020, 8:56 am 
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As Dave said it was about the resulting interface between the connection and wire. High currents immediately tell you about how good the joint is. I once cut a connector that had been crimped on the large wire and the face was solid copper. The wire and lug fused. If you have a good compression tool to crimp any size lugs the same mechanism applies. You can't get lower impedance than the copper of the wire and lug commingling to become one piece of metal.


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PostPosted: June 11th, 2020, 9:40 am 
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tomp wrote:
As Dave said it was about the resulting interface between the connection and wire. High currents immediately tell you about how good the joint is. I once cut a connector that had been crimped on the large wire and the face was solid copper. The wire and lug fused. If you have a good compression tool to crimp any size lugs the same mechanism applies. You can't get lower impedance than the copper of the wire and lug commingling to become one piece of metal.


In our real DIY world we do not do much in the way of splicing wire together. I found crimp connections to be a pain-in-the-ass and only as good as the crimping tool allows. However, I do prefer and have used many times the Western Union splice.

it's easy to do, can be covered with shrink tubing to continue the insulation and I found it to be ever so reliable. For those that are not aware of that option here is a link that explains it:


https://en.wikipedia.org/wiki/Western_Union_splice

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PostPosted: June 11th, 2020, 11:30 am 
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I have used that splice method before but never knew he name. it is physically good for preventing separation under tension. However it works best on solid, not stranded wire. This from Wikipedia about the Western Union splice:

This type of splice is more suited to solid, rather than stranded conductors

You are also correct that the crimp is only as good as the crimping tool. Simple pliers type crimpers will not do a proper job. Also you are generally better using uninsulated terminals because the insulation does not interfere with the crimping action and then use heat shrink.


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PostPosted: June 11th, 2020, 12:42 pm 
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tomp wrote:
I have used that splice method before but never knew he name. it is physically good for preventing separation under tension. However it works best on solid, not stranded wire. This from Wikipedia about the Western Union splice:

This type of splice is more suited to solid, rather than stranded conductors

You are also correct that the crimp is only as good as the crimping tool. Simple pliers type crimpers will not do a proper job. Also you are generally better using uninsulated terminals because the insulation does not interfere with the crimping action and then use heat shrink.


Same with solid vs. stranded using Sta-Kons. Solid works best for splicing.

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PostPosted: June 11th, 2020, 3:09 pm 
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Even with smaller stranded wire wire in the range of 18 to 22 gauge, I have done tests with uninsulated terminals and crimped them. After cutting a cross section, again their was no demarcation of the strands of the wire and the terminal. The crimps were done with a high quality crimper that had ratcheting jaws so a complete compression cycle had to be done before the crimpers opened. A good crimper frame can be used with different die sets. Here are a few links.

http://www.lashenelectronics.com/p-2357 ... gn=Paladin

http://www.lashenelectronics.com/c-243- ... -sets.aspx


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