SERIOUS Crimping tool recommendations - Page 2 - PeachParts Mercedes-Benz Forum

deanyel · #16 05-04-2009, 06:58 PM

Quote:

Originally Posted by tinypanzer

FWIW, I would recommend soldering the wires wherever you can. Even the best crimper is second fiddle to a properly soldered joint.

Not to contest it, but do you have any scientific or semi-scientific support for that claim?

Richard Wooldridge · #17 05-04-2009, 08:32 PM

Do NOT solder connections where they are subject to vibration. The wire will break on one side or the other of the soldered connection. This is from over 50 yrs of experience, learned the hard way.

deanyel · #18 05-05-2009, 12:53 AM

Quote:

Originally Posted by Richard Wooldridge

Do NOT solder connections where they are subject to vibration. The wire will break on one side or the other of the soldered connection. This is from over 50 yrs of experience, learned the hard way.

For goodness sakes, tell us what we are supposed to do.

compress ignite · #19 05-05-2009, 01:55 AM

AND use lots of "Heat Shrink" for strain relief.
(AND Liquid Electrical Tape on top of that!)

deanyel · #20 05-05-2009, 09:27 AM

American Boat and Yacht Council?

Richard Wooldridge · #21 05-05-2009, 09:33 AM

Crimp and use heat shrink tubing for at least 1/2" on each side of crimped connection. The soldered connection will act like a solid piece of wire, and will cause breakage at the edge of the soldered area.

OldPokey · #22 05-05-2009, 09:48 AM

Quote:

Originally Posted by Richard Wooldridge

Crimp and use heat shrink tubing for at least 1/2" on each side of crimped connection. The soldered connection will act like a solid piece of wire, and will cause breakage at the edge of the soldered area.

The solder is not there to make the connection, it's really only there to hold the wire and connector together and to prevent corrosion. A properly crimped and insulated connector will also do this, without the breakage problem. Aerospace connections are all crimped for that reason.

deanyel · #23 05-05-2009, 09:55 AM

Coincidentally I'm headed out today to buy some adhesive shrink tubing, which happens to be, from my source anyway, a 3 to 1 shrink ratio rather than 2 to 1 for the non-adhesive. It seems like the adhesive should help to hold things together - doesn't cost much and I can't see that it could hurt anything.

tinypanzer · #24 05-05-2009, 08:10 PM

Well obviously, soldered connections have the drawback of making the wire less flexible at the area near the joint, and repeated vibrations will make the wire break. It is essentially the same thing as stranded versus solid core wire. Stranded wire can bend, and solid wire will fatigue if repeatedly bent. When you solder the end of a stranded wire, you essentially make it solid.

Soldered connections are better electrically speaking because there is no chance of oxidization forming between the wire and the terminal. No crimp can guarantee you that. Also, a crimp is essentially a mechanical connection and is subject to loosening over repeated heat/cool cycles.

Obviously you don't want a solder joint on some spot where the wire will repeatedly bend or vibrate, but really one should use strain relief and tie downs to prevent that anyway since a crimp connection is susceptible to vibration too.

Take a look at the connections in a W126 for example. If you open up one of the multi-pin plugs you will see that the wires are soldered into the terminals and not crimped. Everything in the fusebox, same story. Soldering is way more labor intensive than crimping so it stands to logic that MB had a very good reason for choosing to solder them.

Take a look inside a 50 year old guitar amp. All point to point soldering. Guitar amps vibrate plenty, and you don't see wires falling off inside these things even after 50 years. Look inside a new guitar amp. All ribbon cables with crimped ends. They just don't last as long. Mackie mixers are another example. They had to replace all the ribbon cables in mixers that were only a few years old because they couldn't take the most minor vibration.

I'm not saying that all crimped connections are poor, but that you will almost always in my experience see a lower failure rate from a properly soldered joint.

Richard Wooldridge · #25 05-05-2009, 08:24 PM

Ribbon cables don't have crimped connections, they have insulation-displacement connectors, which are not the best solution in the world. I certainly agree that a soldered joint is an excellent way to go, provided that there is adequate vibration protection. A soldered joint inside a connector doesn't sufffer any vibration because the cable connector has a mechanical holdment for the wires. Most all Mercedes (and other automotive) circuit boards have potting compound on the components, or are heavily sprayed to hold the components in place.
In short, I really don't see anything to argue about here, just trying to make sure that people don't expect a soldered joint to hold permanently on wiring subject to vibration, as when mounted on an engine. A crimped connection is always the preferred way to go in that case. But, look at Tektronix scopes - they won military certification for their soldered joints, even though the components were only laid in the connectors, because they used silver solder on all the joints, and the joints were then just as strong as joints that had a mechanical wrap, as the military had required up until then. (more than 3/4 wrap and less than 1 1/2 turns wrap.) I worked for IBM on the SAGE computer system back in 1959-61, and every soldered joint had to be inspected by an airforce quality control person. Believe me, they would reject a joint that wasn't properly made according to their military specs!

mytmousemalibu · #26 05-05-2009, 08:55 PM

Been an automotive tech, i see wireing problems quite often. In older BMW's, the wire loom that passes between the door/pillar or trunk/body and so on, we see wire breaks in side these looms somtimes. Of course these are all strand-type automotive wire, and over A LOT of repeated flexing, some of them break. Tryed and tested, the best way to repair the problem is to cut out the entire section of wire thats subject to repeated flexing and soldered in a new section, and heat shrinked. IMO, unless crimped connections are sealed, soldiering is better, giving the nature of wires placment. I have seen more than once, a crimped connection causing a voltage drop/exess resistance where as a proper soldiered connection wont affect the ohm's . As far as flexability, yes soldiering does affect that very much. I have seen crimp conections do the same though too. it does render some of the wire unflexable. We also often see soldiering ring-breaks in some circut boards. Caused by vibration and generally larger, higher current circuts, easily fixed by re-soldiering. So in all, IMO there is a individual proper connection for each wire for its givin purpous, location, etc.

The crimp connectors with shrink tube integrated are very nice!

pmckechnie · #27 05-05-2009, 09:25 PM

I have been keeping track of this thread just to see what others think. I have been using Thomas & Betts hand crimpers for years. I have only had one connection fail in over 40 years and that was caused by an accident. In automotive, 95% of the electrical system is made from 18 to 10 guage wireing. I use UNinsulated connectors with heat shrink. I have done a lot of boat trailers that are run into the water and never had to redo a connection. I have built quite a few complete wireing harnesses including a 1941 White halftrack (old military half truck and half tank) and never had any electrical problems caused by one of my crimp connections. It works, and works good. It is quick and easy. I have however repaired MANY soldered connections. Keep in mind that solder is an electrical connection, NOT a mechanical connection and you will be OK.
Expensive tools are not required for auto work. Use good quality connectors, wire, and heat shrink and about $50 to $60 dollars for tools and you can do just about anything you will need to do. Battery cables? I do use solder made for the purpose, the correct size connectors for the cable and heat shrink. They look as good as factory made cables.
We buy most of our supplies from a company named Del City. They have good products and very good prices. www.delcity.net

Paul
Paul's Auto Electric

tinypanzer · #28 05-05-2009, 09:59 PM

Quote:

Originally Posted by Richard Wooldridge

Ribbon cables don't have crimped connections, they have insulation-displacement connectors, which are not the best solution in the world.

Yes, that's true. They really aren't the same thing, but somewhat similar in that they rely on mechanical pressure to maintain the connection.

Man, I love those old Tek scopes with the ceramic barrier strips and silver soldered connections. I've got an old Tek 535A with the "M" 4 trace input module and a ScopeMobile cart. Those things are truly magnificent pieces of engineering and construction. Mine hasn't been calibrated since the 80's but it still works perfectly. 55 tubes in that thing! Truly amazing. I use it all the time and the 4 trace feature is incredibly useful, so long as you're not worried about anything over 6.5 Mhz......

I wasn't arguing with you at all, I think you're exactly correct!

slk230red · #29 05-05-2009, 11:02 PM

Quote:

Originally Posted by tinypanzer

Soldered connections are better electrically speaking because there is no chance of oxidization forming between the wire and the terminal. No crimp can guarantee you that.

That's why you're supposed to use no-ox on crimp connections. I've installed my share of 48V power plants. Old Bell System power guys always have no-ox in their tool box.

deanyel · #30 05-05-2009, 11:58 PM

Nice thread, very timely for me getting ready to build a wiring harness.

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