Solder vs. Crimp Connections

[curt-s]

Original discussion began HERE.

Why not crimp, solder, then glue-lined heatshrink?
You can even tin the ends before crimping, it still makes a great physical bond.

 

[jdxnc]

Why not crimp, solder, then glue-lined heatshrink?
You can even tin the ends before crimping, it still makes a great physical bond.

Copper gets brittle from heat, which makes the fine strands break easier just past the point of the solder. Not to mention it makes a stiff spot. You'll never find a soldered joint in an oem harness for a reason.

 

[curt-s]

Copper gets brittle from heat, which makes the fine strands break easier just past the point of the solder. Not to mention it makes a stiff spot. You'll never find a soldered joint in an oem harness for a reason.

I've never had a copper wire, stranded or solid core, break at a solder joint without repeated purposeful stress fatigue.They don't even come apart unless the wires weren't clear of corrosion or the joint was soldered cold. Stiff spots make absolutely no difference here as a crimp is also stiff. If crimps were flexible, they would fatigue and break. Crimps are quick, easy, and remove the possibility of somebody f*cking up a harness at the factory because they can't solder properly. Far from fool proof, as crimps have been known to be faulty from the factory as well in certain cases and TSBs, but they do well enough there for the purpose.

*edit: removed some word emphasiseses as they made it sound unnecessarily emotional-like. this is just a conversation.

 

[CrackedDSM]

As stated, just wire it in permanently, you're never gonna go back to a MAF.

But I will suggest crimp and glue lined heat shrink, much better than solder.

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Where'd you get these from/what are they called? That looks so much better than butt connectors.

 

[jdxnc]

I've never had a copper wire, stranded or solid core, break at a solder joint without repeated purposeful stress fatigue.They don't even come apart unless the wires weren't clear of corrosion or the joint was soldered cold. Stiff spots make absolutely no difference here as a crimp is also stiff. If crimps were flexible, they would fatigue and break. Crimps are quick, easy, and remove the possibility of somebody f*cking up a harness at the factory because they can't solder properly. Far from fool proof, as crimps have been known to be faulty from the factory as well in certain cases and TSBs, but they do well enough there for the purpose.

*edit: removed some word emphasiseses as they made it sound unnecessarily emotional-like. this is just a conversation.

I've seen many wires break next to a solder over the years of working on cars, copper embrittlement isn't a myth, it's a fact. Some were due to shitty work but others just from vibration and movement over time. A proper crimp will allow far more flex in a wire than a solder joint.

Where'd you get these from/what are they called? That looks so much better than butt connectors.

You can get them in many different sizes for different gauge wire:

Amazon.com

You also need the crimpers, these are a decent budget pair for the home game:

Amazon.com

Cut some strands of wire and practice first till you get the hang of it.

 

[Stapl3]

I just got these crimpers in this Monday. They are incredibly nice. This is the first week I've made the change from soldering to crimping. Well, for terminal ends anyways. For two wires spliced together I'm still on the soldering wagon but that's just me being set in my old ways.

Can't get the link to work. Eliminate the space after the .com.

Copper gets brittle from heat, which makes the fine strands break easier just past the point of the solder. Not to mention it makes a stiff spot. You'll never find a soldered joint in an oem harness for a reason.

Imagine the labor cost of soldering wiring in a harness over crimping. I do agree with you it is better durability-wise. I feel like the connection is better flow-wise if properly spliced and soldered. So for something like the maf pigtail, I'm with crimping it. For rewiring my fuel pump and having to splice a wire, I'll solder as in my head it's a better quality connection flow-wise.

 

[jdxnc]

I feel like the connection is better flow-wise if properly spliced and soldered. So for something like the maf pigtail, I'm with crimping it. For rewiring my fuel pump and having to splice a wire, I'll solder as in my head it's a better quality connection flow-wise.

Solder has lower conductivity vs pure copper as well. I've seen figures as high as adding 10-20% to the resistance(depending on the type of solder, the more expensive stuff has more silver in it), mind you that may only be a few milliohms but it adds up the more joints you make. One thing I learned when making my own harness is crank/cam sensors are extremely sensitive to connection quality and anything you can do to keep the resistance to a minimum is very important.

Those crimpers you linked are good for the normal shielded terminals but not compatible with the style of crimps I listed.

 

[Stapl3]

Solder has lower conductivity vs pure copper as well. I've seen figures as high as adding 10-20% to the resistance(depending on the type of solder, the more expensive stuff has more silver in it), mind you that may only be a few milliohms but it adds up the more joints you make. One thing I learned when making my own harness is crank/cam sensors are extremely sensitive to connection quality and anything you can do to keep the resistance to a minimum is very important.

Those crimpers you linked are good for the normal shielded terminals but not compatible with the style of crimps I listed.

To use your style crimp, you would need your style crimper opposed to mine?

Good info on the solder resistance. Thanks for that. I recently was doing my pumps with nickel plated [I think] PTFE wire, it's silver color and seemed to be very high quality compared to stuff I've used before.

 

[jdxnc]

To use your style crimp, you would need your style crimper opposed to mine?

Correct.

The Jaws fold the tabs around onto the wire and the sheething.

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I am an incredible human being. All of my threads end up randomly containing extremely valuable information from experts.


You're all f**king WELCOME, OKAY.

Thanks for the opportunity to share the knowledge

 

[curt-s]

Solder has lower conductivity vs pure copper as well. I've seen figures as high as adding 10-20% to the resistance(depending on the type of solder, the more expensive stuff has more silver in it), mind you that may only be a few milliohms but it adds up the more joints you make. One thing I learned when making my own harness is crank/cam sensors are extremely sensitive to connection quality and anything you can do to keep the resistance to a minimum is very important.

A solder joint adds resistance more than a pure strand of unbroken copper wire, yes, but so does an imperfect bond between metals via just clamping force. We're also talking extremely minute differences in DC resistance when quality solder is used. Tenths of milliohms. Tenths of milliohms add up to tenths of milliohms, which you can create by having a few feet of wire.
The amount of oxidation on the wire harnesses in these cars increases DC resistance and lowers conductivity/current carrying capacity far exceeding that of a solder joint.
Relying on only physical contact, such as that by clamping, instead of a metallic bonding mechanism, further reduces current carrying capacity. Of course, in low voltage signalling, that doesn't matter so much.
Rule of thumb: just don't use shitty Aliexpress solder. The higher the silver content, the closer you get to copper. If we could all afford it, we'd just use silver wire since it's better than copper.

 

[Stapl3]

The higher the silver content, the closer you get to copper. If we could all afford it, we'd just use silver wire since it's better than copper.

Help me as this is contradictive.

 

[curt-s]

Help me as this is contradictive.

Silver is less resistive and more conductive than copper.
Solder is higher resistance than pure unbroken copper, tin/lead being worse than an actual electronics grade silver based type. But there are varying percentages of silver in different types of solder so the higher the percentage of silver, the less resistance it exhibits. You can approach the level of pure copper wire but you won't quite reach it due to the other components that make up solder dragging it down, so to speak. However, solder is still used everywhere for good reason, even in highly sensitive electronics. It forms a bond and ensures proper physical interface between conductors at all times.

So effectively what solder does do is it encompasses the strands in a wire and bonds to them all around their surface, rather than a clamp force just pushing some together and making parts of them touch. No wire is perfectly smooth so only parts of the wires are touching at a microscopic level even though it looks like all of them.
That means you're able to transmit more current between wires and makes the wires more conductive between each other via a soldered joint than a crimped one.

The thing to remember is the use case. For what we are discussing, low DC voltage signalling and current in the milliamps, clamping works fine. Soldering works just as fine as well. I prefer solid joins where possible, have not had issues with them in decades and you're not leaving anything on the table when using a good grade solder and proper wire cleaning and joining technique. As I said, oxidation of the wires affects them far worse.

I respect @jdxnc position. I don't agree with him on every point here but that's ok

 

[CrackedDSM]

Silver is less resistive and more conductive than copper.
Solder is higher resistance than pure unbroken copper, tin/lead being worse than an actual electronics grade silver based type. But there are varying percentages of silver in different types of solder so the higher the percentage of silver, the less resistance it exhibits. You can approach the level of pure copper wire but you won't quite reach it due to the other components that make up solder dragging it down, so to speak. However, solder is still used everywhere for good reason, even in highly sensitive electronics. It forms a bond and ensures proper physical interface between conductors at all times.

So effectively what solder does do is it encompasses the strands in a wire and bonds to them all around their surface, rather than a clamp force just pushing some together and making parts of them touch. No wire is perfectly smooth so only parts of the wires are touching at a microscopic level even though it looks like all of them.
That means you're able to transmit more current between wires and makes the wires more conductive between each other via a soldered joint than a crimped one.

The thing to remember is the use case. For what we are discussing, low DC voltage signalling and current in the milliamps, clamping works fine. Soldering works just as fine as well. I prefer solid joins where possible, have not had issues with them in decades and you're not leaving anything on the table when using a good grade solder and proper wire cleaning and joining technique. As I said, oxidation of the wires affects them far worse.

I respect @jdxnc position. I don't agree with him on every point here but that's ok

All jokes aside, I love shit like this. Active discussion dropping knowledge I had no clue on before.

Any links or brand names to "good" solder? Like basically what would YOU use on wires in the engine bay.

 

[curt-s]

A SAC (SbAgCu) solder is a good choice without breaking the bank, which is tin/silver/copper. It's popular due to not containing lead, and it still makes a strong join. Your higher end stuff is silver alloy (~5% Ag) and the really high silver content solder is best left for joining things made of or plated in silver.

When it comes down to it, we are talking about super minute differences and things can often get blown out of proportion. Even the most expensive oscilloscopes out there aren't using some unobtaniumn solder to affix their ICs, and they use more solder in a single 4Ghz pathway than you will in a wire join (if done properly )

It's important to clean the joint with flux so that you can get the solder to flow quickly and bond fast, so that you don't apply too much thermal stress to the joint and the solder bonds properly. I don't like relying on the flux in flux core solder to do that job but I also prefer solid core.
The crimps are still nice to have because they immobilize the joint.. not good to have a moving joint while the solder cools otherwise you can end up with a cold joint. Not all solders go directly from liquid to solid in a flash.

For electronics work, I generally look for stuff in the 2-5% silver content range. That way I'm also keeping it consistent with what hits my soldering tips.
Stuff like this is just fine (hope this link works): https://www.digikey.com/en/products/filter/solder/262?s=N4IgjCBcpg7ALFUBjKAXATgVwKYBoQB7KAbRHgAZ4BWSkAXQIAc0oQBlTASwDsBzEAF9BBAEykQAZ0IAbACY4MDAgDYkILnLYBaMBQjNWkECAJoAnkxxsAhpNTCgA

Personally I'd have no qualms about this when I need to restock my solid core: https://www.digikey.ca/en/products/detail/chip-quik-inc/SMD-SC-SAC305-0-031-1OZ/22592574

Flux/rosin core is plentiful, you can use that.
Crimps will also work for what you're trying to do. You have much option. By combining both, you're still allowing the crimp to do its thing which is just pushing copper wire up against copper wire, but that physical contact is still not 100% due to irregularities in wire and crimp surfaces. The solder fills the holes between the surfaces.
If physical copper to copper contact occurs, electricity will follow that path as it's least resistance, but it will also flow the solder path because it exists. That's where you have additional current carrying capability.
It's similar to why we use thermal interface material and thermal paste on heatsinks.
Metal to metal just isn't enough in all situations.

 

[jdxnc]

I respect @jdxnc position. I don't agree with him on every point here but that's ok

As long as you're not a twist & tape guy I can respect that

 

[1990TSIAWDTALON]

So, no "vampire taps" or wire "nuts"????
Dam........

 

[curt-s]

As long as you're not a twist & tape guy I can respect that

Tape? That's for amateurs.
I just lick my fingers first and twist the wires together. Tie them in a knot after and you're good to roll

 

[Stapl3]

Tape? That's for amateurs.
I just lick my fingers first and twist the wires together. Tie them in a knot after and you're good to roll

You joke but the amount of times I've seen that stuff on cars I get my hands on is incredible.

 

[curt-s]

You joke but the amount of times I've seen that stuff on cars I get my hands on is incredible.

I never joke about twisting wires. Or licking my fingers.

Yes, the wiring hack jobs and blobers (my name for solder blobs that I made up just now) I've seen a-plenty as well.

 

[Stapl3]

blobers

I'll just put that word in my back pocket. Applicable to welds as well.

There's not many things more satisfying than the wire hitting the right temp and the solder sucking into the connection.

 

[Dusty Landrum]

So here is my experience. I have been doing 6v-12v DC/AC wiring and troubleshooting since I was 16 and now 39. I have worked on and seen every type of wiring "repair" you could probably imagine, including tar. Yes, melted tar. From MY experience and even when I was MECP certified, it was to ALWAYS solder a repair or connection. It is always better than any crimped connection. Not talking about anything 8awg and up of course. Anything lower than 16awg is way more delicate and should be done with more care but still solder. High quality wire prep tools and quality solder gun/pen, solder and covering are of course going to make a difference as well. Those cheap strippers hanging at autozone are not the way to go . Always know the AWG wire you are working with and strip/cover accordingly. Like stated before, the amount of resistance added from the solder is extremely low and the joint is not supposed to be caked in with solder. Melt TO the heat, not on the heat and wait for correct heat. This will ALWAYS (IMO) beat any crimped, friction holding connection. I now work in the aviation field and it has changed the way I look at most things now as far as avionics quality control goes, but that is a whole different discussion haha.

 

[jdxnc]

I feel this is one of those subjects where there will never be a solid answer one way or the other and everyone has their own opinion. I USED to be a solder guy until I built my own harness from scratch. Using quality tools helps a lot and in the hands of idiots, both methods can be terrible.

FWIW, even the guys at Haltech and HP Academy prefer crimp over solder, at least for 90% of applications in the auto industry. Solder does have its place but in my personal opinion, it's not in most of an automotive wiring harness.

Some good watches:

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[Dusty Landrum]

Again, I disagree with you on this Jason. I also laughed at the videos (Wanted to be fair, so I did watch them). Talking about building harnesses is one thing, but repairing or breaking into/adding to current systems is another. Complete strands are of course going to terminated and should be pinned into connectors, leads etc. First video does not convince me whatsoever that a solder joint will crack and I literally have never, ever seen one. Pressure on a joint is far more common of a failure. I have seen tons and tons of crimped connections fail and break and there is a fail rate to even our calibrated tools here in the aviation industry. Also was more of a plug for Haltech tools. HP academy was an instant NO from me as soon as I found they "pig tail" all their terminal ends. This is completely unacceptable to me and would fail any QC in any avionics industry I have ever worked. I get people say its for fixing a broken wire (in a crimped connection mind you). But it builds in its own resistance and also chaffing is introduced instantly. Add heat and moisture and vibration and compounds. They last part on the last video however is critical and what I feel solves ALL of the issues to either connection.

But in the end you are right, we all have our own opinions and their videos were still just that, opinion. They also highlighted the worse way you can solder a joined wire so that is where I laughed. Poor technique to any connection is detrimental, solder or crimp.

 

[CKOPOCT]

Soldering done right I think provides the best joining of two wire ends. It was what we did to repair broken or spliced wires on fighter jets. The method was very specific, but the soldered joints were expected to (and did) hold up to the intense stress and vibrations a fighter jet might be subjected to. But crimping is easy and provides a descent enough contact for most automotive applications. In the end I think it comes down to the mindset of the one doing the work. Anything worth doing is worth doing right, and a good solder joint or a good crimp, properly protected, should outlast the plastic connectors the wires are pinned to.

 

[1990TSIAWDTALON]

This is a VERY USEFUL thread. Nothing better than talking about it in civilized tones. Where else would you find that...........Well I don't know.
Thank you to ALL OF THE CONTRIBUTORS. I used to repair/upgrade/modifiy CB radios. Sometimes you solder, sometimes you don't, just depending on where its at and what it is.
I truly do like all of the conversation about this!