Electrical Repair – To Crimp or Solder?

HomeArticlesMotorcyclesElectrical Repair – To Crimp or Solder?

Last updated on May 28th, 2021

Most people wouldn’t believe how controversial this topic still is. Should I crimp or solder this connection? Ask this in any forum and you’ll find opponents willing to passionately debate the topic to death.

On one side you’ll find those who will quickly crimp a connection without giving it a second thought and go on with their day. On the other side you’ll find those more than happy to call the first group “hacks” or lazy. They will insist that a soldered connection is much more reliable and has better performance. But who is right? The truth of the matter isn’t that simple. This won’t settle the crimp or solder discussion, but it will provide valuable insight.

To Crimp or Solder, That is the Question

When deciding whether to crimp or solder, consider what method is mostly used by the factory.
If you’re wondering whether to crimp or solder, ask yourself when is the last time you saw a factory soldered joint on your bike?

While it may be painful for some people to hear, the reality is that in the automotive industry this has long ago been settled. The gold standard is to (properly) crimp wires where possible. This is what industry does, and what you should do, too. Whether you’re splicing or attaching a terminal makes no difference. To verify this just take a look under the hood and you’ll find hundreds of crimps, but virtually no soldering. As long as you have the right tools, crimping is the way to go.

Personally, I used to crimp and then solder my connections thinking I was doing myself a favor reliability-wise. I never really considered whether it was better to crimp or solder. Then I had a few electrical problems on some custom systems. They were due to wires breaking due to wire fatigue from normal bending and vibrating, combined with corrosion. Just tugging on the connector you could break off the few strands still holding it together. And this was on a carefully tinned, crimped and soldered connection with a quality wire. Heat and humidity played a huge factor, though. After not insignificant research, it quickly became clear that there are plenty of reasons why you shouldn’t be soldering on vehicles.

Note: The following focuses on wiring or terminal connections for automotive applications – namely cars, motorcycles, electric vehicles, marine, etc. Applications which are subject to vibration, heat, movement, thermal shock or similar challenges. Keep in mind that this does not apply to circuit boards or other cases where the wires are immobilized.

Why is Crimping Better than Soldering?

Crimping is the process of creating a permanent electrical connection between one or more conductors and a crimp terminal in any form. Since crimping was first introduced in the 1940s, it’s made itself a staple in any assembly plant. It’s quick and easy to do, even more so than soldering. It almost feels too easy, which is why some people feel like it’s the lazy way to do things. But surely just carelessly clamping down a terminal on a wire can’t provide a more secure connection than a terminal lovingly hand-soldered by a careful DIYer? Here’s a few reasons why you should consider whether it’s more appropriate to crimp or solder.

Wire Fatigue

The main issue is wire fatigue. With crimped connections, the wire is free to move at its leisure. Copper is fairly flexible when finely stranded, which is great in a vibration-happy environment like next to a running engine. The crimp is designed to hold the wire securely, while also allowing it to move.

When you solder the wire (either before, after or instead of crimping), unless carefully done, the wire stiffens. It might happen due to excessive heat but it mainly happens thanks to solder getting under the insulation by capillary action. If you apply heat too long (using too small a solder iron), it’s pretty much unavoidable. For soldering newbies it’s even worse, as they tend to apply too much solder to begin with.

Another factor when choosing to crimp or solder or vehicles is the repetitive wire movement. When solder gets past the insulation, the wire loses flexibility. Just try bending a soldered wire splice to see it for yourself. If you install it on a vehicle, every vibration is like bending the wire a little bit. Eventually the cables shear off little by little until there is nothing more than a few strands holding it together. As the cable’s effective diameter reduces, the intermittent failure issues start popping up.  Finally, the solder-reinforced wire fails.

This is even worse on motorcycles, thanks to their reduced weight and high vibrations. Furthermore, its wiring is generally exposed to high heat and to the elements (read water) which compound the issue with accelerated corrosion.


At a first glance, it might seem like soldering provides a lower resistance than crimping. Surprisingly, reality differs. A properly crimped connection actually creates a metal-metal colloidal bond at the surface between the wire and the terminal. This makes it effectively gas tight, stopping oxidation inside the joint. The copper-on-copper connection is generally superior to solder considering that most solders have more resistance than copper.

In practice, the difference in resistance between either methods (properly done) is beyond the accuracy range of average multimeters. Hence, the difference  is negligible, especially when working on 12v circuits. By that my point is that soldering will not provide “better conductivity”. Once you see the cross-section of a properly crimped cable, where the individual strands can hardly be distinguished, it’s easy to understand why.

When properly crimped, the individual strands effectively micro-weld together forming a gas tight connection.
When properly crimped, the individual strands effectively micro-weld together forming a gas tight connection.

There are other situations where soldered connections may fare even worse. In a hot engine bay, solder recrystallization can happen over time. This can both increase the joint resistance and lead to cracking. Because of this, solder should never be used to mechanically fixate a wire.  And that’s one reason why the American Boat & Yacht Council Standards excludes solder as the sole means of electrical connection for wire terminations. The same situation applies to many military and aeronautic standards.

Finally, if that isn’t enough to be convincing on if it’s better to crimp or solder, consider this. Tin (the main component of most solder) has about 5 times the resistance of copper. As such, when used in high current applications (think a battery lead), that resistance can lead to heat. Apply enough current and the heat can quickly spiral out of control. The resistance creates heat at the joint, which melts the solder, which increases the resistance until it fails altogether. As unlikely as that sounds, it’s a perfectly valid concern and does happen.

Give Crimping a Chance

I’m sure that many of you would love to call BS and tell me how they’ve used X method for years without ever having a problem. They’ll just crimp or solder depending on if they feel like it or not. Heck, I’d probably even agree with them that what they did was perfect, in their situation. Almost any soldered joint will last forever if done right and strain relieved – that’s the key. Nonetheless, none of that takes away that on a vehicle, a decent crimped connection will reliably be less problematic than a decent soldered one. You may disagree, but this is a well-settled fact.

That doesn’t mean that soldering doesn’t have its place. For light-duty, low current tasks, or where crimping isn’t viable, soldering still is a valuable option. A perfect example is any circuit board. It will simply require extra care and attention to do right. But for everything else crimping should be the default choice.

How Do I Properly Crimp a Connection?

So you’ve made it this far and, though skeptical, you’re willing to give it a try. Problem is, you’ve never given crimping a second thought and always used the chintzy tool that came with your $5 kit. No instructions came with it (of course), so you learned as you went. But, what’s the right way to do it?

If you really want to stop water wicking, consider using an insulated terminal and adding some dielectric grease.
If you really want to stop water wicking, consider using an insulated terminal and adding some dielectric grease.

Tools and Materials

Any project starts with the proper tools and materials. In this case there are several involved.


Regardless of if you’re going to crimp or solder, it’s important to select the proper wire. Don’t underestimate its importance or complexity. There are a daunting amount of wire qualities and specifications for different applications. That includes both the sheathing (PVC, GXL, SXL, TXL…) and the conductor itself (copper, copped-clad, etc…). Click here for a quick overview. Choose the right wire gauge depending on its length and current draw based on a amps-gauge chart.

Oh, and by the way. Don’t judge a wire’s gauge by its outside diameter. Many vendors these days use thick insulation with a thin wire underneath to trick buyers. This is especially problematic when using generic speaker wire for electrical projects.

Crimp Connectors or Terminals

Choose the right Crimp Connector. Not all crimp connectors have the same design, quality, material or strength. When possible choose a high quality kit. For insulated terminals, I prefer nylon (the translucent ones) over PVC insulation. Seamless or brazed barrels are also preferable, as crimping is more consistent.

Depending on the job you may prefer an insulated barrel, or an uninsulated barrel. For ground wires I tend to use uninsulated. Many DIYers prefer to use uninsulated and add their own heatshrink later. If you will be pushing the connector to its current limits, uninsulated is also best as it is easier to get a reliable crimp. But in practice, the decision will depend on the application.

This would be an example of a decent affordable crimp connector kit. There are better, just keep in mind that the high quality kits get expensive, fast. Whatever you decide, make sure to choose the right size for your wires. Thankfully most crimp connectors are color coded as follows:

  • Red: 22-16 AWG
  • Blue: 16-14 AWG
  • Yellow: 14-12 AWG

Wire Strippers

Next comes a quality Wire Stripper. There are many different types and formats depending on the job, so it isn’t really possible to pick out a single style.

On the basic side you have something like the Irwin Wire Stripper/Cutter. It will do the job just fine for cheap as long as you know how to use it correctly. Though personally what I tend to use most these days is the Capri Tools Automatic Wire Stripper/Cutter. I find it easier to use on wires still connected to the vehicle, thanks to its pistol-grip design. Also, its V-cutter helps strip the wire without nicking the conductors or ripping the sheath.

Crimping Tools

And finally a good Ratcheting Crimper. This is probably the most important component, and I wouldn’t recommend skimping. Personally, I use the Astro Quick-Change Ratcheting Crimping Tool. It’s excellent thanks to its quality and multiple jaws. But if you’re on a budget you can get an inexpensive one like this Ratchet Crimping Tool. The fact that it is ratcheting and will automatically release when the correct pressure is reached greatly aids in not over-crimping.

The most important thing to make sure of is to choose one that has the correct jaws/anvils for the job. If you know you will only be crimping one style of terminal, a single fixed jaw is fine. If you are unsure or would rather future proof, a model with multiple interchangeable jaws is definitely preferable. Even better if they can be swapped tool-free.

While it may be tempting to use a Stripper/Crimper/Cutter Combination tool, I’d recommend avoiding them for crimping. Some are decent, some are junk. Personally, I’d definitely go with the ratcheting style considering that nowadays they don’t cost that much. Using the right crimping tool with a quality jaw is going to have the biggest impact on producing a good crimp.

Crimp ‘er Up

Checking your result is just as important as choosing the right method
Checking your result is just as important as choosing the right method – Click to see.

Crimping isn’t particularly difficult, though there is technique involved. While objective, well-defined technical specs on what is and isn’t a well crimped connector exist, the main points to keep in mind are as follows:

  • The stripped wires or remaining insulation should be undamaged – That means avoiding cut or nicked strands. The insulation shouldn’t be tapered or torn where the insulation was removed. Make sure the conductors at the end aren’t cut at an angle, either. All of these are reasons to use a good stripping tool.
  • There are two types of crimping terminals:
    • Closed Barrel Terminals – Here, the portion of the terminal that is crimped forms a closed circle. It is the style typically seen with the opaque plastic insulation included with most budget kits. On this model the crimp barrel should only clamp on the exposed conductors (as opposed to the insulation).
    • Open Barrel Terminals – You will typically find this type installed in modular quick-connect plugs. They have two sets of open “wings”. One crimps over the conductor, and one set crimps on the insulation. Though a bit harder to consistently crimp, they are preferable for automotive applications as they provide better strain relief. Make sure that the conductor crimp is only crimping the conductor, and the insulation crimp is only crimping the insulation. When crimping this type of terminal, using the right tool with the right jaws in crucial. Don’t even look at those needle-nose pliers.
  • The wire strands should slightly protrude from the front of the wire barrel, but not excessively – This should be the case regardless of the terminal type.
  • Correctly place the wire in the terminal before crimping – Center the wire in the terminal and inspect its position prior to crimping. If it is a closed barrel design, you want the seam to be opposite from the detent on the crimping tool. That is called “saddling the seam”. It helps avoid issues with the crimp separating at the seam.
  • Be careful with over-crimping – Over-crimping a connection work hardens it making it brittle and prone to failure. One benefit of ratcheting crimpers is that they will automatically release when they achieve the proper crimping pressure. Of course, don’t under-crimp either since that is just as bad.
  • Where possible, protect the crimp from corrosion – If you are really concerned with corrosion and moisture wicking, you can use some dielectric greaseconformal coating or liquid electrical tape.
  • Add strain relief when possible – Though crimped terminals cope better with repeated bending than soldered connections, don’t abuse it. If the wire will be unsupported and under any strain, at a minimum add some heatshrink as strain relief. Even better if it is the double-walled adhesive variety. That style is sturdier and provides some protection from water ingress thanks to the glue.
  • Inspect each crimp – Give each crimp a light tug as a quick test. You’d much prefer it fail now that you’re working on it, rather than a month down the road. Also, give it a few bends to see if that loosens the wire. If done properly, it should feel secure and trust-inspiring.

Keep all of this in mind and your connections are likely to outlive the vehicle, as most OEM crimps do. As long as you do it right, there isn’t anything to be skeptical about.

What if I Want to Solder a Crimped Connector Anyway?

On some connections, a small amount of solder won't be harmful if done right.
On some connections, a small amount of solder won’t be harmful if done right.

To some people, if the terminal isn’t soldered it just doesn’t feel like a job well done. This is particularly true for people who mostly solder on audio or electronic projects. There, to crimp or solder isn’t even a question. Solder is the de facto gold standard for many applications. Even for me, it took a while to trust crimps instead of soldering. Having done mostly audio wiring, it just didn’t feel right.

However, if you are repairing some high-precision sensor or a component worth the extra effort, you might want to add a dab of solder after crimping. It shouldn’t be necessary as it should be sufficient on its own to crimp or solder. But it shouldn’t harm either (done right). Just make sure the solder isn’t compensating for an inadequate mechanical connection.

To do so, crimp first. Then apply the least amount of solder needed to create a soldered union between the tip of the wire and furthermost end of the connector. That is, you want to apply the solder away from where the wire leads out. The main objective is avoiding solder creeping under the insulation. On open-barrel terminals you might have a bit more leeway since there is a second crimp and a larger distance to the rear end of the connector.

This might be beneficial in that good-but-not-quite-perfect crimp, and can help keep it from moving or pulling through the terminal. Potentially, If you feel the need to do this I definitely recommend adding strain relief.

What about Tinning Wires?

Tinning a wire consists in coating the exposed stripped end in tin. This is frequently done in electronics to aid with later soldering and to prevent fraying. It might be beyond the scope of the “better to crimp or solder” debate, but it’s worth touching on. Nonetheless, to do it or not for automotive applications is questionable, at the least.

Per the IPC (Association Connecting Electronics Industries), IPC-J-STD-001 Rev E, page 13, section 5.1.3stranded wire shall not be tinned when the wire will be used in:

  1. Crimp terminations
  2. Threaded fasteners – terminals which clamp the wire with a screw
  3. Mesh splices – when splicing wires together

Basically if you’ll be crimping or securing it with a screw in a terminal, you shouldn’t be tinning it. The reasons are two-fold. When the screw closes down on the wire it could break the solder joint making it susceptible to vibration, loosening and corrosion. A second problem is that tin flows slightly at low temperatures which may lead to unchecked loosening later on. I’m sure the fact that introducing less conductive tin in between the copper and the connector doesn’t help either.

Unless you will be soldering the wire to a circuit board later (which can happen, even on a bike – see my decoy alarm project for GPS trackers), I’d avoid it. However, an exception might be if you are still designing and testing a mod and will be disconnecting/connecting the wire frequently. Then I might tin to keep fraying at bay. If that isn’t the case, I’d try to avoid it for this type of job.

I Have to Solder Instead of Crimp – Any Tips?

Okay, so you’ve read all of this, and you are willing to consider it might not be BS. But…you have to fix a problem now and you don’t have time to order a proper crimping tool. Plus, plenty of people solder so it can’t be that bad. What can we do to avoid issues with a soldered connection down the road?

As long as you take the right precautions, of course soldering is good enough for most tasks. The main things to make sure of are:

  • Ensure that no solder gets under the insulation – Use the proper tools and technique. Remember, solder tends to migrate towards the heat. And don’t use the soldering iron to directly melt the solder.
  • Completely immobilize the soldered section – This is specially important with splices. If done, it avoids the connection work-hardening itself to death. Heatshrink is generally the best solution, as long as you plan in advance. Use two layers or more if needed, and adhesive heatshrink is best since it is thicker. Electrical tape sucks for this job, but you can use it as a last recourse. There should be enough strain relief to keep the joint from moving at all. Of course, avoid using solder unsupported in high vibration applications.
  • Solder is not a substitute for a good mechanical connection – Never use solder to hold the wires together. That’s a recipe for failure. In many cases doing this is what starts the conversation on if it’s better to crimp or solder.
  • Use the right size soldering iron – Applying gobs of solder isn’t a substitute for the wrong tool or poor technique. Avoid using an under or over-sized soldering iron. A variable soldering iron is often useful for this reason. If the connection is too large to solder with the tool you have, stop. Crimping or securing with a screw-terminal is probably a better idea.
  • Use electronic rosin core solder, and clean later – Rosin core solder helps solder components in less than ideal conditions. That means dirty and oxidized wiring. Since rosin flux only turns acidic when heated, it is typically considered “no-clean”. However, engine bays are hot so I always recommend using some cleaning alcohol in a small squirt bottle to clean off the residual flux. And of course, don’t even consider using acid core plumbing solder.

Is it Better to Crimp or Solder? – Conclusion

Though completely unrelated, let's take a moment to indulge the wiring-OCD in all of us. Oh the beauty of hundreds of well-organized, crimped network cables.
Though completely unrelated, let’s take a moment to indulge the wiring-OCD in all of us. Oh the beauty of hundreds of well-organized, crimped network cables.

The key takeaway? Crimp where you can, solder where you have to. Though soldering a wire or connection on a vehicle may make you feel like you are doing a better job, in practice it can cause more issues than it may avoid. To crimp or solder will be a personal decision based on experience, tools and preferences, but in general crimping should be the go-to option. All in all, I’d prefer a decent solder over a bad crimp, but a good crimp over either. On vehicle repairs, at least.

At the end of the day, whether to crimp or solder and how you decide to work is up to you. This is just food for thought for the avid DIYer, and I can only hope that it provides you more context to better make that decision yourself.

Got a whole different opinion altogether? Got any tips or suggestions? Feel free to leave them in the comments below.

References & Good Reads

18 Replies to “Electrical Repair – To Crimp or Solder?”

  1. I came across this article as a was googling rewiring my motorbike. It’s an older bike that I’ve added a few modern conveniences too, but has ultimately made the loom behind the headlight very congested, and was seeking to find advice on what others had done… and as usual I’m amazed at those who wave the soldering iron about like its some sort of one-size magic wand that makes everything better.

    your article is a breath of relief amongst the insanity of the pages of poor advice being offered on the internet.

    what is missing from from your article is a bit more depth about solder itself and why it has only very specific uses. The article has touched on the properties of “solder”, but fails to highlight solder isn’t solder, there are hundreds if not thousand of different types of solder – some shouldn’t even be considered for use on wiring. in my stock I have 4 types: Kester44 60/40 roll, Kester 245 63/37 roll, kester331 63/37 roll, and some solder paste equivalent to the kester331 63/37. only one of those types would I ever consider being suitable for using with flex wire, and it’s not the type that most would use in the comparison between crimp and solder.

    you did mention how soldering flex wire can wick up under the insulation creating a point of stress, what also happens is the flux wicks up the strands of wire first. and the second part of the join creates the other “bee in my bonnet”. IMO heat shrink only exists to hide dodgy workmanship, the only thing it does better than keep moisture out is to keep it in – so it inevitable that it will trap moisture in the join, in combination with cheap rosin-cores flux will eventually corrode the wire away, yet hold the parts together whilst hiding the failure from view- I’ve seen this failure so many times it angers me. the other frustration is tinning wires uses in pressure/compression terminations, but that was covered in the article.

    the same principle applies to heat shrink, there are hundreds of different types, most not suitable for the applications they are being used for.

    if the need is felt to solder and heat shrink is the best way forward, consider the both the type of solder and type of heat shrink.

    and please use only clear heat shrink.

  2. Nice article, i wish more people could understand this.

    NEVER solder wires in a mobile application, or high current load.
    Its a simple concept, Dont do it!

    Your best, and most reliable connection ALWAYS comes from a CORRECTLY crimped splice.
    And i dont mean some plastic coated bullshit from Wallmart you squish with a pair of pliers.

    Butt connectors are just that, butt connectors. If you want the wires to overlap use a parallel connector.

    Good connectors are usually made of copper with a tin coating to prevent the copper from oxidizing.

    Speaking of oxidizing, the wire isnt going to have any oxidization layer if i just stripped it a minute before i crimp it.

    Solder is for circuit boards, if you are working on a circuit board solder away.
    If you are working on wiring in a mobile application crimping is always the best way.

    Fyi, in the aircraft maintenance world (my chosen trade, im an A&P) the crimp v/s solder debate was settled long ago, it is illegal to solder aircraft wiring, PERIOD!
    It can ONLY be crimped as per FAA regulations. For safety, and long term reliability.

    NO U.S. certified aircraft has soldered wire connections. If any soldered “bubba” connection were found the aircraft would be grounded immediately!

    (But what do those aeronautical engineers know? Im sure you soldering rednecks are just as smart.)

    Usually using Molex parallel connectors, and a ratchet crimper, with the connection covered with shrink wrap.

  3. The crimp or solder debate will continue well beyond this discussion lol. The elephant in the room for me is doing something a certain way because that’s the way the manufacturer did it. If you follow that precedent you could well be setting yourself up for failure. Many manufacturers will perform a task a given way simply because it saves them money. Whether to crimp or solder depends entirely on the task at hand. Everything from having the proper training, tools, environmental conditions, time, etc all come into play. For example this discussion centers on the automotive industry. Various conditions that vehicles must endure on a daily basis include shock/vibration, temperature extremes, confined work space, etc. This I am sure adds to the desire to crimp electrical connections. I was trained to always make a good mechanical connection to whatever a wire was connected to. That keeps everything held in place. I was also trained to solder the same connections when appropriate (splices, wire looms to connectors, etc). Soldering provides a good electrical connection. The ideal is to achieve both. The problem is conditions don’t always allow for that. That’s when your training and experience help you make the best choice in those situations. Sometimes there are specific requirements to make repairs – and it is wise to follow those requirements.
    34 year journeyman electronics tech – component level.

    1. Can’t say I disagree on the premises. One aspect would be if you’re soldering/crimping because what the manufacturer did failed, or because it’s a new modification. Also, the “they want to make money” goes both ways – Servicing vehicles under warranty isn’t cheap, and a faulty electrical system doesn’t lead to brand loyalty or more sales.

      But yeah, conditions and execution are certainly crucial. I still have my doubts that solder is better for electrical work if viable, but I guess the lack of compelling evidence either way is why the debates still rages on. Thanks for the input.

    2. Yes, exactly. My industry solders all splices (shrink tube insulation). But, our installs are not subjected to the vibrations that an automotive install is.

  4. In regards to using the “proper crimping tool”, this would be quite expensive, as the proper crimping tool is the tool recommended the the manufacturer of the terminal. While the advice of using a ratcheting hand tool is great, the actual crimping jaws in the tool need to be correct as well. You can get the generic open barrel crimping jaws, which will do okay, but the likelihood of getting an OEM level crimp is very unlikely. Every terminal manufacturer has engineered the proper shape of their crimps and has designed tooling, whether a hand crimping tool, or the high speed crimping dies used by the manufacturer of the wire harness.

    As someone who works in the wire harness industry, I can tell you that we literally have hundreds of different stamping dies that are specific to each individual terminal (or a small family of similar terminals). Prior to production the dies are set to provide the specific crimp height, based on the manufacturers design of the terminal with each appropriate wire size. Most terminals are specified for 2-4 different AWGs, even among the same connector family. As well, prior to production, after the proper crimp height is set, destructive pull tests are performed to the appropriate specification (or UL, SAE, NASA, etc). There are other process controls involved, without getting into too much detail, but proper crimping is a complex issue at the OEM level. If not done properly, you can generate thousands of scrap wires in a hurry. I have to say though, this article was very well written and had some valuable point to make!

    1. Thanks for the detailed comment, Mike. It’s really insightful. I completely concede all of those points, and it’s great to have some input from someone in the field. One can definitely go down the engineering rabbit-hole with these types of topics, and the article was long enough as-is to even think about delving deeper into some of those aspects. But of course, it’s definitely worth keeping in mind. Personally, I call it a win just to have been able to open some people’s minds on the “Solder is always better!” topic.

  5. Coming from the automotive industry, I would just like to point out that the reason the “crimp vs solder” question is answered for us is not because crimping is superior in all situations, but cheaper/faster. In an instance where a human needs to physically make an electrical connection (that is, when a machine can’t do it), the extra cost of the connector is still cheaper than the extra time lost to a skilled laborer spending time soldering.

    In manufacturing, especially car manufacturing, time spent on process is everything; speed and repeatability make successful mass-products. Crimping is easier and faster, and we don’t really care about the current rating on cars since current spikes are so brief (seconds, not hours).

    A properly crimped cable makes a very good connection against the oxide layer of cables and connectors, adding a miniscule amount of resistance. A properly soldered connection uses rosin flux (or acid flux on aluminium joints) to remove the oxide layer, creating actual metal-to-metal contact and vastly reducing resistance, even when the main component is tin. Even if a crimped connector gets over 90% of the wire surface contact, it is still contact with the oxide layer.

    1. Thanks for the detailed input, it’s appreciated. That it’s cheaper/faster also implies that it’s easier/more reliable, as it if it weren’t the case, it wouldn’t be cheaper/faster. It’s a given that it isn’t superior in all situations – but then again, what is? Neither is soldering, for that matter.

      Regarding oxide, that’s definitely a factor, but like pointed out above, that’s “just” one among many. Someone has other problems to worry about if the oxide coating is severe, and in principle most connectors are nickel/gold/etc plated to mitigate that. The flux can also create long term problems if it isn’t cleaned, and it seldom is (no clean-fluxes generally rely on the fact that their acidity is temperature dependent, but automotive applications are a lot hotter than most other electronic applications). Finally though oxide might marginally increase resistance, so can the soldering compounds (vs a bare copper connection). Not to repeat other aspects to take into account.

      All in all, I get where you’re coming from, and it’s because of valid points like this that this article starts by pointing out that this will always be an eternal debate.

  6. Good post and well written.

    The key to both is a PROPER install. Many can do neither properly. If one chooses to crimp, please use a proper ratchet-type crimp tool and quality connectors and terminals. If one chooses to solder, yes, solder properly by using just enough solder so that strands are still defined and solder does not flow under insulation. Also, use proper strain relief on both.

    The goal of both is to create a mechanically strong, gas-tight connection (no loose contact or oxidation, both of which will increase resistance). Yes, that can definitely be done by crimping alone.

    For me, I crimp and solder, but I’m experienced in both. I have noticed that some of my terminal crimps do not form the gas-tight cold weld needed. I presume it’s because of the slight differences in terminal and wire sizes allowed within spec. So, I crimp and then flow in MINIMAL solder at the front of the terminal, basically soldering the exposed wire ends to the terminal barrel. I then add shrink tubing for strain relief. I have never had an issue.

    As for soldering vs. crimp, I think Honda’s vehicle terminals and connectors are crimped AND soldered. No? Yes?

    Anyway, thanks for the article. Well done!

  7. I had a question about butt connectors generally. I’ve read papers that indicate that crimping theoretically (if done correctly) results in the best conduction and least resistance. Isn’t the point of crimping to make airtight connections between the wire and the thing you are connecting it to so the soft metals merge? But in the case of wire to wire connections most butt connectors I’ve seen have the indentation that prevents wire overlap (especially in smaller guage wires) and necessarily creates a gap. So you end up relying on whatever metal the barrel is made of for conduction between the wires and hoping it doesn’t introduce resistance. Wouldn’t wire to wire contact ensure a more complete conduction and wouldn’t the best butt connector permit overlap between the wires? I’m guessing the increased resistance in most cases is negligible but still why don’t most butt connectors allow for overlap.

    1. That’s definitely a great point.

      In an ideal world, I do imagine the connection would be with wire-to-wire contact, but in the real world I suspect it creates more problems than it solves. I’d imagine it’s harder to get a reliable connection in the field as the wires may slip past each other, they might not make proper contact, or they might bunch up and create a larger air gap than the one it was supposed to avoid. Or practical issues like creating a connection over double the diameter when done inline. But considering that good crimp connectors are typically clad copper or some other material that conducts at least as well as the wire they’re connecting, I don’t think it’s a huge issue. But I definitely think its a reasonable objection to bring up.

      1. Just following up – thanks for the reply. After my post, I did find that there are connectors that permit overlap – they are called parallel connectors and you can get them on at supply outlets, Amazon, etc.

        My post was prompted because I had to attach a replacement oxygen sensor connector/pigtail to the wiring that runs to my SUV’s engine control computer. The repair was self-induced – when I replaced the oxygen sensor I didn’t secure the wiring far enough away from the exhaust pipe and the oxygen sensor connector and wiring got fried.

        I hadn’t come across the parallel connectors at the time I made the repair. So I ended up using butt connectors with copper tubes and doing everything possible to ensure proper connections in order to connect the replacement pigtail to the sensor wiring coming from the engine computer. My SUV has two downstream oxygen sensors and the engine computer sends a signal with the same voltage to each oxygen sensor. So I tested the signal strength at the connections at the end of both the repaired wiring and the unrepaired/unbroken wiring. The signal coming to the end of the wiring that was repaired with the butt connectors was nearly identical to the signal coming to the end of the other wiring- actually it had a slightly higher value showing less resistance than the unbroken wiring. The difference between the two for purposes of the sensor was so small as to be negligible. So from my experience butt connectors can provide lossless (or nearly lossless) connections.

  8. Crimping is not the way to go especially on today computerized vehicles. Computer works off resistant values and adding to a wire will increase resistance throwing codes while you’re scratching your head trying to figuring out why. I wanted to keep it short so be careful electricity still has rules

      1. I agree – I just posted a reply to your earlier message. In my experience, using butt connectors for my automotive application (replacing oxygen sensor wiring) introduced no detectable resistance – none.

  9. Brilliant post! This is the best post I have ever read. I think it is very informative and very interesting. This will be very useful for everyone who works in this field. I really enjoyed reading this post. Thanks for this great article. Do keep posting.

  10. Brilliant read up that.
    Very informative.
    I use to be a solder buff, but found myself making work by soldering parts of the bike loom.
    This article has just strengthened my new way of looking at altering or making new wire looms.
    I already have the tools for the job.
    Thanks again

Leave a Reply

Your email address will not be published.