Why you should not use solder on wiring harnesses.

turbocharged798

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I found this good discussion via google, I know its a boating fourm, but still shows you why you should not use solder joining two wires together:

http://www.sailnet.com/forums/gear-maintenance/40595-crimping-versus-soldering.html

Bottom line is VW states to not solder on the harness, VW does not use any solder on the harness, boaters say not to use solder on a harness, so why to people continue to insist on using the stuff? IT IS DOING IT WRONG, period. Use proper adhesive lined heat shrink butt crimps with a good crimping tool. Always give the wires the tug test before shrinking down the connectors. If it fails the tug test, then the connection must be redone. A proper crimp is stronger than the wire its self.

Only place solder should be used is in PCB boards. Wires should be crimp only. VW agrees with me. :)
 

burpod

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unfortunately, if one were to use good quality butt connectors to build an entire wiring harness for a whole car (eg, mk1 tdi swap :D)... that would have cost a small fortune for butt connectors alone!... :eek: it's just not practical, and the wiring will likely outlast the car or me, regardless...
 

N41EF

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Just my somewhat quallified opinion here. A boat or car in a salt environment will have corossion everywhere. If exposed the tin and lead in solder will weaken and break down, causing a weak joint and poor electrical connection. We saw this on magnetic amplifiers on the submarines built in the early 60's. Through quality assurance we developed procedures and methods for repairs and instalation to prevent the failures. Convormal coating, or heat shrink was used to protect the solder joint.

NASA also followed suit, after wiring problems in the Apollo program they got pretty serious about it.

Immpoper solder joint allow for "wicking" where the solder runs up the wire under the insulation. It is caused by using too much heat or having the heat applied for too long. Most of this can be prevented by using eutectic solder 63/37 which has no plastic region and goes from liquid to solid as it cools. Use a 25w iron an keep the heat on the joint for the minimal time. You can buy 63/37 solder at radio shack, it isn't much more expensive than the cheap stuff.

Food for thought, in a the nuclear program the only termination allowed for a wire was for it to be soldered to a terminal or in a properly crimped mil-spec lug that was screwed to terminal. Butt crimps were specificaly not allowed and if a wire required required repair it was twisted, soldered and shrink wrapped, and would be replaced when practical.

Yes, a good butt crimp using a proper crimper will give a good connection, but butt crimps also increase the bundle size. Crimps with heat shrink built in such as for boating are even better.

All being said, if I was replacing a 4 wire glow plug harness on MY car, at home, where I have all of the tools, I'd solder it , shrink it individualy and again as a bundle. In a parking lot at a GTG butt crimps and electrical tape would work.

I'm restoring a 1979 Chrysler sailboat now, replacing all of the wiring, no splices, crimped terminals to the breakers, and soldered to the end load, or again a crimped terminal.

Closing, if you have the right tools, and right materials in a clean environment solder is much better. If not a crimp isn't going to be a bad thing, but not really a permenant thing.

For the record, I'm a retired Navy Nuke, Chief Electronics Technician, and was quallified as a Electronics Technician Maintenance Technician Instructor. I've done a taught a little soldering in my time.
 

ymz

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I've been soldering things since my teens... never had problems with anything that I soldered... Perhaps I've never used good quality crimpers or crimp connectors, but I have not had long-term success with them...

Just my experience... solder and shrink-wrap is my normal routine...

Yuri
 

compu_85

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Mercedes soldered the harness ends on all their older cars. I found no issues at the ends... and they were not in water tight connectors. The corrosion on both 91 cars was about the same.

-J
 

whitedog

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Favorite post:

"And none of the old threads discussing this wouldn't have been adequate to revisit the issue?"

(Post 5 of 259)

I didn't read past the first 10 replies though.

There was this other one: "The only reason for soldering wires is because marine grade tinned wire is not being used". So does this mean that if you aren't using marine grade tinned wire with marine grade connectors, it's better to solder?
 

N41EF

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"Marine Grade" wire has been tin coated for extra corrossion resistance. It also makes it easy to solder. The copper when exposed is what corrossion hits first and can actually look perfect but have little or no electrical connection.

If you strip a wire and it looks silver, it's tin coated. If it is copper colored it's not. Aircraft and boat places usually have the tin coated wire. I bought a huge stock at Skycraft near Orlando years ago, still using it here and there.

If you are using a crimp and heat shrink it's not a big deal.

Tinned wire is MUCH easier to solder correctly.

Regular copper wire can be soldered but it needs to be clean, IE no skin oil from touching it, clean it with rubbing alcohol prior to soldering it.
 

FlyTDI Guy

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Working for a world class boat mfg. used by the military, law and enforcement agencies world around... we solder and marine grade shrink wrap. The weak points of solder are vibration and exposure to the elements. Marine grade shrink wrap is a great product and seals the connection 100%. Most commonly available butt connectors (neighborhood AP store style) are not quality products. I never use them unless it's the only logical solution to a wiring problem. Unprotected, they suffer in the elements as well.
 

whitedog

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"Marine Grade" wire has been tin coated for extra corrossion resistance
OK. I was confused. I thought it was the stuff marked "Semper Fi". :)

The thing is, you could read that to mean it's ok to solder on wire that isn't Marine grade.
 

megaladon6

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i have just as many problems with crimps as with solders. crimps create a non flexible point on either end, the wire still tries to flex and eventually breaks. the pressure also reduces the cross section, and flexibility. same problem as they complain about in a solder connection. though i've found that by interweaving the strands and properly soldering, then electrical taping and heat shrinking that corrosion and stiffness are minimized.
crimps are great for quick connections and long runs where you can tie down the crimp and keep it from moving. but overall, just learn how to solder!
 

whitedog

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There's just so much fear in that thread:

"A quick immersion in water (I don't know where from, maybe your bilge pump is shot or you're sinking) could very quickly open a live wire internally."

If you're sinking, wire corrosion is a small problem.

And:

"Some insulation might be PVC-based and as such, heating it might release Hydrogen Chloride gas...which when added to water becomes Hydrochloric acid."

Unless you solder it then immerse it in water, Hydrochorlic acid won't be an issue. Or maybe you are soldering in the rain, or possibly while sinking because you are fixing your bilge pump wiring.

And that's just in the first page.
 

tditom

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i have just as many problems with crimps as with solders. crimps create a non flexible point on either end, the wire still tries to flex and eventually breaks. the pressure also reduces the cross section, and flexibility. same problem as they complain about in a solder connection. though i've found that by interweaving the strands and properly soldering, then electrical taping and heat shrinking that corrosion and stiffness are minimized.
crimps are great for quick connections and long runs where you can tie down the crimp and keep it from moving. but overall, just learn how to solder!
A good crimp connection provides strain relief by also securing the insulation so that the wire strands won't be flexing outside the insulation and therefore cannot individually flex and break. It is difficult to solder a connection without the solder wicking up inside the insulation and creating a brittle point that can then start breaking a few strands at a time due to movement. This can be helped by using a thermal sink to avoid wicking under the insulation and heat shrink to provide some strain relief where the insulation is missing but heat shrink is not as good of a strain relief as the insulation. I'm not saying soldering can't be done- just that it is difficult to do when you have very limited space as in a vehicle.

How does crimping reduce the cross section? That is defined by the sum of the cross sections of the individual strands.
 

40X40

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I use a pound of 60/40 Kester about every six months. Some of my connections just get soldered OR crimped, others are crimped AND soldered, still others are crimped, then soldered and then glue type heat-shrinked.

I just do the best I can for each connection. My original instruction in soldering was to NASA specs and my instructor was retired from Fermilab.

Bill
 

burpod

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oooohhh.. nice link jimbote, i'll be saving that for the future :) i'd love to use nice butt connectors for certain connections, and the oem vw ones are nice, just so much $$
 

PDJetta

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If I could find some professional wire connectors and a good crimping tool, I'd propably use them. My experience from the 1980s with those Radio Shack krimp connectors is that after a while the wire fails to make proper connection in the connector and/or the wire pulls out of the connector. For a while there I was using those connectors, but soldering them to the wire.

With that said, I do make automotive wiring connections by soldering and using heat shrink tubing. I never had one fail. Eight years ago when I bought my '04 Jetta, I installed the Phat Noise hard drive music box. Somehow I fubared the 30 plus prong connecter that attached to the CD changer plug. I simply cut it off and soldered every one of the wires to the CD changer harness. 30 or so soldered connectins. Still works fine 8 years later.

I will say that when I do solder and heat shrink, I tie secure the wire so the connection won't vibrate.

Thanks for posting the link. I'm going to read it today. I did look at the first post and this caught my eye:

"EVERY soldered joint on the V-42 we have is corroding and failing. It may have taken close to 20 years to do it, but we did not find these issues on ANY of the crimped joints... NONE." Note that the issue is corrosion. And that it takes 20 years to occurr. This has to be in the salt air/wet environment since this is on a boat. Our cars are in a totally, less corrosive, environment.

--Nate
 
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PDJetta

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here's where I buy all my heat shrink butt connectors....they have hot glue inside that seals the connection.... http://gcs.cableorganizer.com/?q=krimpa-seal .... works out to around .25 to .30 a connector for the common sizes ....also have this torch for heat shrinking em' .... http://www.eddyproducts.com/ItemDetail.aspx?itemId=03
That heat shrink torch is slick! I just ordered one. Everytime I heat shrink wrap tubing using a lit match (only gets one side well), I think, "There has to be a better way to shrink the tubing".

--Nate
 

VWBeamer

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I agree, soldier joints fail because people are not soldiering correctly.
I work on military aircraft and almost all connections are soldiered.

I want to add that after soldiering, any excess flux needs to be removed. It attracts and holds moisture and this is what is causing corrosion. If it's removed with a solvent then the corrosion problem is reduced greatly.


Just my somewhat quallified opinion here. A boat or car in a salt environment will have corossion everywhere. If exposed the tin and lead in solder will weaken and break down, causing a weak joint and poor electrical connection. We saw this on magnetic amplifiers on the submarines built in the early 60's. Through quality assurance we developed procedures and methods for repairs and instalation to prevent the failures. Convormal coating, or heat shrink was used to protect the solder joint.

NASA also followed suit, after wiring problems in the Apollo program they got pretty serious about it.

Immpoper solder joint allow for "wicking" where the solder runs up the wire under the insulation. It is caused by using too much heat or having the heat applied for too long. Most of this can be prevented by using eutectic solder 63/37 which has no plastic region and goes from liquid to solid as it cools. Use a 25w iron an keep the heat on the joint for the minimal time. You can buy 63/37 solder at radio shack, it isn't much more expensive than the cheap stuff.

Food for thought, in a the nuclear program the only termination allowed for a wire was for it to be soldered to a terminal or in a properly crimped mil-spec lug that was screwed to terminal. Butt crimps were specificaly not allowed and if a wire required required repair it was twisted, soldered and shrink wrapped, and would be replaced when practical.

Yes, a good butt crimp using a proper crimper will give a good connection, but butt crimps also increase the bundle size. Crimps with heat shrink built in such as for boating are even better.

All being said, if I was replacing a 4 wire glow plug harness on MY car, at home, where I have all of the tools, I'd solder it , shrink it individualy and again as a bundle. In a parking lot at a GTG butt crimps and electrical tape would work.

I'm restoring a 1979 Chrysler sailboat now, replacing all of the wiring, no splices, crimped terminals to the breakers, and soldered to the end load, or again a crimped terminal.

Closing, if you have the right tools, and right materials in a clean environment solder is much better. If not a crimp isn't going to be a bad thing, but not really a permenant thing.

For the record, I'm a retired Navy Nuke, Chief Electronics Technician, and was quallified as a Electronics Technician Maintenance Technician Instructor. I've done a taught a little soldering in my time.
 

ymz

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That heat shrink torch is slick! I just ordered one.
They were pretty much being given away by Canadian Tire about a year or so ago ($10.00 and then for a short while $5.00)... I guess they weren't selling well... I bought a couple...

Yuri
 

vwdieseling

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I know that solder is not recommended for automotive connections due to its ability to attract moisture and salt corrision. There are some applications in which vibration and movement require a solder joint. I had an ABS wire at the sensor on driver side steering knuckle that had broken and needed splicing. I tried connectors of various kinds and it would always brake at splice. I finally resorted to solder and heat shrinks. I then booted it to prevent moisture. It was the only solution, though I know better. This is not a marine application, but there is potential for road salt and water to enter splices. I was trained not to do it, though the Marine Corp diesel manual gives instruction on how to. A Zinc Chloride solder does resist salt corrosion versus tin lead based.
 
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Herm TDI

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I'll add my 2 cents to this thread.
The corrosion issue is related to the type of soldering flux paste used.
Many brands of soldering paste contain Zinc and Ammonium Chloride compounds. It is these compounds that cause galvanic corrosion within the solder joint.
The use of "acid free" soldering flux will make a lifetime solder joint.
The other issue is contamination during the soldering process. Keep the soldering tool, solder and the surface to be soldered clean and "brite".

I've used soldering flux such as


I've never had a single solder joint that failed as a results of corrosion or a cold joint.
 

JSWTDI09

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I also know that butt connectors is the recommended way to connect wires in a car. However, there is sometimes not enough room to do so. When I "upgraded" to a HomeLink visor, I had to install a new connector on the visor so that it matched my car. I tried to use a butt connector and discovered that there was not enough space above the head liner for the connector and the butt splice. I had to take it apart again and solder the wires. It was not the ideal method, but it was the only method that would work. Sometimes you just gotta do what you gotta do.

Have Fun!

Don
 

JB05

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also I use channel lock wire crimpers ....http://toolguyd.com/channellock-wire-crimper-tool/ and I always use the "non insulated" section of the tool to crimp my insulated terminals:D...just makes an unbeatable connection plus the glue seals up the break in the plastic jacket that part of the tool can create....
I have the same exact crimpers I bought directly from Channel Lock. I needed something that would fit in tight places and these did the trick. The non insulated section does seem to work better on the insulated terminals. They work pretty well on the VW type terminals as well.
 

nicklockard

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There's just so much fear in that thread:

"A quick immersion in water (I don't know where from, maybe your bilge pump is shot or you're sinking) could very quickly open a live wire internally."

If you're sinking, wire corrosion is a small problem.

And:

"Some insulation might be PVC-based and as such, heating it might release Hydrogen Chloride gas...which when added to water becomes Hydrochloric acid."

Unless you solder it then immerse it in water, Hydrochorlic acid won't be an issue. Or maybe you are soldering in the rain, or possibly while sinking because you are fixing your bilge pump wiring.

And that's just in the first page.
:D That cracked me up :D
 

nicklockard

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I'm no expert in soldering, but I did do it in a production environment for a stint during a college work-study job. I've done a smattering here and there and never had any of my joints fail. My technique for butt joints

  • clean the connection with alcohol or acetone (low residue/high purity stuff)
  • twist wires and thread into butt connector
  • Crimp on either end to proper rating w/ratcheting tool
  • tin your solder tip very well! a lot of people don't properly pre-tin the working end and this causes thermal stresses in the finished product. even heat distribution is critical to good solder work.
  • heat the ends of the butt connector and wire (jam the tip down there) and feed a tiny amount on the same end opposite from your tip. (Use low non-acid flux solder). This will bond wire to wire and both to the butt barrel.
  • Slip the heat shrink over and seal it well.
  • prior to reassembly of the wire into the bundle or into its run, make sure it is well supported for strain relief and pay attention to the turn radius if the wire is routing around other stuff. i.e. short wire run with soldered butt joint must have gentle arc or you'll have to find slack or support it well so it doesn't get pushed or turned too hard by normal contact when servicing the equipment. (basically just good routing practices.)

If you overflow too much solder or it wicks back to bond too many of the exposed threads, you can sometimes get away with using wicking wire to remove excess.

I know with a good crimp connector and tool you don't even need to, but I guess I've always had the low budget crimps and tools (I'm not a professional ET, so it's not worth the investment). Never could trust those cheapish butt connectors w/o the solder. Had most of them fail sooner or later, usually sooner.
 
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snakesausage

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I always solder, it is a much better electrical connection and you not have the issue with breaking the strands or making loose connections like when crimping (most of us do not have proper ratcheting crimpers). Soldering is just a more repeatable deterministic method of joining wires. If my joint is subjected to the elements I will usually put a dab of silicon calk around the wire and slide the heat shrink down over it and then force a little in each end. When I shrink it down it seals up water tight. It is messy but I have never had a solder joint fail. Using the correct flux, no clean or acid free, is key.

I build cables at work on a regular basis (for indoor use only) and on the high current connections we crimp and then solder. If you keep the heat localized (quick or low temperature) you can minimize the wicking effect.
 
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