Soldering irons

I have worked in the electrical trade most of my working life. Everything from rewinding motors during my apprenticeship, to being chief electrician on offshore drilling rigs.

Both crimps and soldering have their place, but the problem with soldering on automotive wiring as an example, is that the solder will "wick" up the conductor and cause it to become brittle. With vibration it can lead to breakages. The bigger the cable the more prone it is to this problem. On big 800hp DC traction motors the leads are always crimped, just like starter motor cables should be. Just as with solder, the preparation and application of the correct tool is a must.

The picture of the old Scope soldering iron sure bought back memories. I still have one somewhere. They used to be available in stainless steel, and back in the 1960s I remember fitting some long leads and alligator clips on one for my mate that had a crayfishing boat.

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Originally Posted by loanrangie

I have seen bad crimps and bad soldering so i dont think either is a perfect solution and both can fail, i would trust a good soldered joint with heat shrink added before a crimped joint.

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That's a personal viewpoint. However, its not borne out by engineering facts. A crimped connection is governed by 3 variables. Wire gauge, crimp pressure and type of crimp. An operator can be trained very quickly to become highly accurate with a crimp tool and produce good crimps with close target parameters.
Now take soldering. The parameters are much less controllable. That's the reason why all solder joints used in military aircraft and spacecraft are x-rayed.
I say this because I've come across too many arguments stemming from lack of engineering knowledge on solder joint properties where your life could depend on it. Suppose someone on this forum takes it as gospel that a solder joint with covered with heatshrink is undisputably the best and goes ahead and does that for a critical connection. How do you know the solder had flowed correctly ? How do you know that flux hasn't built up between the metal-solder interface ? How do you check the joint is still intact when you cover it with heatshrink and install it in the vehicle, bending the connection point in the process ? Extend that over a few years ..with someone inexperienced in soldering.
That should be sufficient examples.
As you have said, there are bad crimps produced too. However, its easier to produce a good crimp than a good solder joint, in relation to automotive connections.

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Originally Posted by GlennD

That's a personal viewpoint. However, its not borne out by engineering facts. A crimped connection is governed by 3 variables. Wire gauge, crimp pressure and type of crimp. An operator can be trained very quickly to become highly accurate with a crimp tool and produce good crimps with close target parameters.
Now take soldering. The parameters are much less controllable. That's the reason why all solder joints used in military aircraft and spacecraft are x-rayed.
I say this because I've come across too many arguments stemming from lack of engineering knowledge on solder joint properties where your life could depend on it. Suppose someone on this forum takes it as gospel that a solder joint with covered with heatshrink is undisputably the best and goes ahead and does that for a critical connection. How do you know the solder had flowed correctly ? How do you know that flux hasn't built up between the metal-solder interface ? How do you check the joint is still intact when you cover it with heatshrink and install it in the vehicle, bending the connection point in the process ? Extend that over a few years ..with someone inexperienced in soldering.
That should be sufficient examples.
As you have said, there are bad crimps produced too. However, its easier to produce a good crimp than a good solder joint, in relation to automotive connections.

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This is all interesting and no doubt correct. However ( :D ) I have never seen an aftermarket crimp on connection on a car that hasn't failed the gentle tug test... ie: the wire just pulls out if you tug on it. I reckon on cars soldering is the only 100% failure free way to go. Not in a million years is the joint going to fatigue and die in a car, especially if the harness is tied down so it can't move,

You simply can't compare manufactures wiring crimps (likely done with 20ton crimpers) the aftermarket merde used on cars :)

seeya
Shane L.

When using crimp terminals I take the plastic bit off first, slide some heat shrink onto the wire, crimp it then heat shrink over it. Works very well and looks a bit tidier.

Some years back I had friends in the RAAF who worked on electronics. They had to do a high reliability soldering course. After every use of the solder, they had to snip off the end of the solder wire to expose fresh resin.

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Originally Posted by Debacle

When using crimp terminals I take the plastic bit off first, slide some heat shrink onto the wire, crimp it then heat shrink over it. Works very well and looks a bit tidier.

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I use these crimp terminals

https://www.aulro.com/afvb/images/im...016/06/458.jpg

I have the right tool to fold the tabs in like this (actually, better than this):

https://www.aulro.com/afvb/images/im...016/06/459.jpg

"I have seen bad crimps and bad soldering so i don't think either is a perfect solution and both can fail, i would trust a good soldered joint with heat shrink added before a crimped joint."

A good clean well taped and shrink wrapped joint is preferable wherever conditions and/or load is concerned, the crimps should (IMHO) only be used inside the vehicle and for very light loads.

The number of times I have had to rewire someones trailer plug because of corrosion in crimp fittings has been ridiculous.

My choice for wire soldering is one of those cheap little gas "Hot Devils", a twin pack comes with various tips for hot cutting, and could be used for soldering on circuit boards, something I have nothing to do with. The direct gas flame is ultra quick, clean and shrinks the heat tubing as well.

Regards

Mike

"I have seen bad crimps and bad soldering so i don't think either is a perfect solution and both can fail, i would trust a good soldered joint with heat shrink added before a crimped joint."

A good clean well taped and shrink wrapped joint is preferable wherever conditions and/or load, the crimps should (my opinion) only be used inside the vehicle and for very light loads.

The number of times I have had to rewire someones trailer plug because of corrosion in crimp fittings has been ridiculous.

My choice for wire soldering is one of those cheap little gas "Hot Devils", a twin pack comes with various tips for hot cutting, and could be used for soldering on circuit boards, something I have nothing to do with. The direct gas flame is ultra quick, clean and shrinks the heat tubing as well.

Regards

Mike

Oh, and I do have a 'Scope' iron at home

Quote:

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Originally Posted by GlennD

That's a personal viewpoint. However, its not borne out by engineering facts. A crimped connection is governed by 3 variables. Wire gauge, crimp pressure and type of crimp. An operator can be trained very quickly to become highly accurate with a crimp tool and produce good crimps with close target parameters.
Now take soldering. The parameters are much less controllable. That's the reason why all solder joints used in military aircraft and spacecraft are x-rayed.
I say this because I've come across too many arguments stemming from lack of engineering knowledge on solder joint properties where your life could depend on it. Suppose someone on this forum takes it as gospel that a solder joint with covered with heatshrink is undisputably the best and goes ahead and does that for a critical connection. How do you know the solder had flowed correctly ? How do you know that flux hasn't built up between the metal-solder interface ? How do you check the joint is still intact when you cover it with heatshrink and install it in the vehicle, bending the connection point in the process ? Extend that over a few years ..with someone inexperienced in soldering.
That should be sufficient examples.
As you have said, there are bad crimps produced too. However, its easier to produce a good crimp than a good solder joint, in relation to automotive connections.

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I agree with Shane - I believe your experience and viewpoints are quite valid and I've seen plenty of awful soldering in vehicles which wouldn't (and haven't) lasted 12 months, so I see your point, but personally, I hate the crappy crimps that most people use - I use the style Ron showed when connecting relays, etc, but for joining wires, etc I'll always solder. I have been doing this for decades and cars I've done this on 20 years ago are still fine - my RRC is a 'Classic' example (pun intended) - I modified the wiring loom over 20 years ago for the Farther in law when he first bought it - grafted some new column controls in from a Japanese vehicle and under the bonnet I moved some stuff which required extending the wires - these joints are all still fine and serviceable, over 300,000KM later.

I am an Electirican though and I've been soldering regularly since I was 13, so I do get your point about guaranteeing quality of work which a lot of well intentioned hobbyists may not be able to do on a consistent basis, but my experience shows that my soldering can live long term on a vehicle so that's the way I'll keep doing it. :)

Oh, and for soldering irons, I have about 8 I think, including good quality gas powered units to a home made scope iron (made in the training annex at the SEC when I was a first year apprentice), 2 temperature controlled units, a big arse thing I inherited from somewhere, and a variety of standard small to mid range irons.:)

On the car, I would usually grab the scope iron unless I'm doing something on a PCB or similar.

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Originally Posted by p38arover

Some years back I had friends in the RAAF who worked on electronics. They had to do a high reliability soldering course. After every use of the solder, they had to snip off the end of the solder wire to expose fresh resin.



I use these crimp terminals

https://www.aulro.com/afvb/images/im...016/06/458.jpg

I have the right tool to fold the tabs in like this (actually, better than this):

https://www.aulro.com/afvb/images/im...016/06/459.jpg

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I have lots of those terminals and the crimper to go with them. Unless the wire size and terminal is perfect, they still fail the "gentle tug" test .... almost every single time.

So I crimp them, and then solder the wire to the terminal ............... The terminals almost NEVER match the exact size required in automotive wiring in my experience :(

Looking at that picture, I reckon gravity would be enough to make that terminal fall off. There is no compression on the conductor or insulator at all.

seeya,
Shane L.

Quote:

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Originally Posted by DoubleChevron

I have lots of those terminals and the crimper to go with them. Unless the wire size and terminal is perfect, they still fail the "gentle tug" test .... almost every single time.

So I crimp them, and then solder the wire to the terminal ............... The terminals almost NEVER match the exact size required in automotive wiring in my experience :(

Looking at that picture, I reckon gravity would be enough to make that terminal fall off. There is no compression on the conductor or insulator at all.

seeya,
Shane L.

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I left that bit out of my write up - I do the same. :D

Never had one come adrift. :)