Soldering vs Crimping

[Ivan]

Interesting about that Western Union and such joints. When I do solder, usually because I have run out of weather proof crimps and the parts store is an inconvienient 30 minutes away, I use the Macintire type joint and then flowe the solder into it with plenty of flux. Done right, the joint will not be any larger than the insulation on the oiriginal wiring. Good quality weatherproof heat shrink will make a durable long lasting splice.

Still, in all reality, vibration and corrosion are the enemies of electrical connections. On my machines (Model helis, cars, motorcycles, and what not) I spend a lot of time making sure the wiring is routed well and is secured and as neat as possible. I think this is the most critical step in any wiring repair, because any crimp, solder joint or even (God have mercy on the blasphemous and evil) twist and tape will not fail as quickly with a stable wiring harness. Indeed, I go through zip ties and wire loom at an alarming rate. But, I know I never have to worry about electrical joints failing because they break at the splice.

Psycoreffer, I hope your twist and tape comment was in jest, because I got a few select words for you if not.

[psycoreefer]

I always just twist the two wires together and then put some tape over them....

I know a guy who uses wire nuts for everything...so where to wire nuts fall, between solder and proper crimps?

[81xsproject]

Wow. Serious controversy and heated debate in a electrical connector thread; I never would have pegged this one for a Hot Topic

[GARTHXS]

this is getting good

almost as good as your harley thread Steve, very interesting and more than I ever really wanted to Know about connections, but seriously how do you keep the smoke from coming out of the wires

[crazy steve]

...ABYC standards prohibit soldering as the sole means of making a connection so I tend to follow up with flowing on some solder after making a good mechanical connection...

So, if you survive the onslaught of "holy water" splashed on you, somewhere near the end of this thread I'd like to hear your views about splices??

I'm not worried; after their solder joints fail, they'll be too tired to do anything after pushing a 600 lb motorcycle to my house!

You bring up one other thing with the ABYC standards; the importance of crimping first. Crimp connectors work poorly on single-strand wire (and if you've soldered first, that's what you have) and even if you do more soldering after crimping, you still probably have a solder-only joint. But solder after is no better, as now you have more mass to get hot and the chances of wire damage go up.

I know about the 'western union'; there's also the rat-tail, end fixture, back turn, britannia, and scarf types to name a few more. Virtually none of them are used any longer in the electrical industry; they all went out with solder. The last users of soldered joints were the utility companies for high voltage splices (who don't fall under the NEC by the way) and they ditched it as soon as the HV 'kits' came out. Some of this is maybe still used in the telephone industry though, but I doubt it. The few times I used any of these, it was used to either add a wire to a conduit run or replace a damaged or too-short wire; the splice was pulled through and out. Splicing of any wire, while allowed under certain conditions, is frowned on.

How do I splice on bikes/cars? Two ends, I use a butt splice. Three to four wires (one and two, or two each end), I'll calculate wire area and use the appropiate size (example: two #14 are roughly equal to a #12 in area). If need be, I'll 'fill' one end by doubling the wire. Any more than that, I'll stagger the splices or take them to a terminal, but I try very hard to avoid 'extra' splices; every joint is a potential trouble spot. The interesting part about your NASA specs is they specifically tell you not to locate any joint where there may be flex and stress proper support. And all of these look to be 'electronic' type splices, not 'power'. I'm somewhat surprised they even allow splicing on spacecraft, I wouldn't like it.

On an unrelated side note, one thing I did when I built the harness for my chopper (starting with several 'partial' harnesses) was to have only two grounding points. I put a 'main' grounding terminal under the seat (tied with #12 directly to the engine case along with the battery cable) and ran a #12 from it to the headlight bucket. Here, I put in a 'ground buss' (just a piece of 3/16" aluminum with a bunch of tapped holes). Everything behind the motor went to the 'main', all the rest went the front 'ground'. Any ground issues, I only have two places to look, and no worries about exposed/rusty connections. It took very little extra wire to do this.

'78E original owner

[Larrym]

Two Ends Make Up the Middle???

crazy steve,

Ok....Ya got me with you on the "solderless" end-connector. (Though every time I crimp I'll also cringe cause I do so love to get out my soldering station..) That's cause I really do use the ABYC standards on my boat and it's so hard to switch behavioral gears when I work on anything else.

The ABYC standards prohibit soldering as the sole means of making a connection so I tend to follow up with flowing on some solder after making a good mechanical connection. (Not as in "the bigger the blob-the better the job.") I'll try to resist the compulsion for every little bullet and spade connection I see from now on.

After the barrage of arrows coming at you slow down maybe we can find out what you do for splices??

Am I the only one who does this:



The oldest telegraph splice - the original mainstay of telegraph wire connections is known, appropriately enough, as the Western Union joint. 'Cold' (that is; not soldered - just twisted together), it is about 65 percent efficient and retains about 55 percent of the strength of the wire. Soldered, it becomes over 95 percent efficient.

or this:



Just twist two wires together - - - You probably have been making McIntire joints for years and didn't know there was a name for them. The McIntire joint is made by grasping two opposing wires at a midpoint about two inches from the ends and wrapping each end around the wire at least four revolutions. Cold, the McIntire joint ranks as about 70 percent efficient and retains about 75 percent of the strength of the wire. Soldered, it also becomes over 95 percent efficient.

or sometimes this:




Though not really the standards most PO's live up to, I'm used to following rules similar to:

THIS.

It comes from working on robots/machinery that did move and vibrate. The western union splice was approved at least in that environment.

So, if you survive the onslaught of "holy water" splashed on you, somewhere near the end of this thread I'd like to hear your views about splices??

If you don't survive...well, I'll be the guy in the back of the angry mob as you're carried off to the already growing burn-pile. Nothing personal. I just like waving a pitch-fork or carrying a torch as much as the next guy.

[crazy steve]

Clint:

Uh, isn't that what I said?

I know the NEC has nothing to do cars, planes, etc. I merely brought this up to show that people smarter than me say it's a bad thing used in the wrong place.

There are some very cool vehicle wiring connector methods out there, but they're not particularly cheap. Tyco and Deutsch are two types I've used personally. The Deutsch is my fav when I can afford it, with crimp-on pins/plugs, and cool little silicon seals for everything. But at about $5 for just a two-wire plug, and over $20 for a eight-wire, you can have a lot of money in a harness real fast...

'78E original owner

[clcorbin]

Ok, I'll take these in order...

Tod: No, you still are confusing electronics and electrical. Yes, solder is commonly used in the electronics industy, and on more than just circuit boards. And they don't refer to 'Aircraft Electrical', but call it 'Aircraft Electronics'. But in the electrical field, solder connections are illegal 'unless part of an approved assembly', i.e. is a factory assembled item and has a testing lab approval such as UL. If I had a current copy of the NEC, I could quote the pertinent section but what it says is ALL field connections 'shall be made by mechanical means', no exceptions.

Steve,

I hate to tell you this, but the NEC has absolutely NOTHING to say about the wiring on plains, trains and automobiles (or boats...). NOTHING. Neither does the Underwriters Laboratory.

There are two huge issues with any electrical connection on an automobile: corrosion and mechanical stress caused by vibration (your house just doesn't sit there and buzz for hours on end. At least, I hope it doesn't!).

Corrosion is fairly simple to address. You have to make sure no air or moisture (or other crap) can get to the joint in question. Good connectors do this with proper seals and sealing gel. The other stand by is adhesive lined heat shrink tubing over a splice or connector (if possible).

Vibration is another ball game all together. Let's look at an inline splice (aka: hacking the wiring harness!) first. In an uncut strand of wire, the forces are passing through all the strands of the wire (Notice that you will NOT find solid strand wire on things that move. Vibration is why.) Because each strand is very small, the actual bending on each section of wire is very small. The more flexible the joint has to be, the small each strand is and the greater the number of strands to get the current carrying capacity needed. Also, the continuous insulation over the wire helps to carry the mechanical loads (bending and other) while at the same time provides damping to the vibrations to keep the amplitude down.

What happens when we put a solder crimp in there with maybe a single wrap of electrical tap to insulate it? Well, in the zone where the wires are physically soldered, that wire is now acting like a single, large diameter wire. Plus, there is no continuous layer of insulation over the joint, so there is no mechanical support nor any damping. Over time, the vibration will fatigue and eventually break the wire very close to the splice. The amplitude of the vibration will determine how long this will take.

If we place a layer (or two) of our good, adhesive heat shrink tubing over the splice we do two things to improve it: Moisture and air can no longer get to the soldered joint (and even exposed copper wire) to support corrosion, and we have mechanically supported our splice as well as dampened down the vibration at the splice. All good things. But the soldered splice is STILL acting like a single large wire and it WILL fatigue and fail before the multistrand wire around it would.

When we upgrade this soldered splice to a crimped splice, we take that "single large wire" problem out of the picture. That DOES improve the splices ability to withstand vibration and it DOES increase the life of the joint.

Now Tod was talking about something ALL TOGETHER DIFFERENT than this type of splice. He was talking about a solder cup Cannon plug ASSEMBLY. This plug uses pins with a small "cup" on the end of each pin that the wire is inserted into and then soldered in place. By itself, this connection would have the exact same problems as our soldered splice example.

But the plug is an assembly. It has additional components that restrain and dampen the wires movement inside the plug assembly. When it is put together properly, there is almost no vibration relative to the wire and the pin, therefore there is almost no fatigue at that joint.

These things are fantastic, but they cost an arm and a couple of legs EACH. The huge advantage of them is you can replace a damaged pin without having to cut the wire back. Field repairs can be done without coming up with some "slack" in the cable assembly (which you won't find on most aircraft wiring harnesses anyway) by unsoldering the damaged pin, cleaning the wire and soldering it to a new pin before reassembling the Cannon plug.

As for crimping damaging the wires, well, yes and no. A properly made crimp with the correct terminal for the wire using the CORRECT crimping pliers and CORRECT procedure will not damage the wire. It WILL deform each strand slightly as the group of strands are tightly compressed together inside the connector. But they won't be nicked, stretched or damaged in any way.

The real trick here is using the correct tools. Those $30 parts store crimpers are not the correct tools. Depending on the connector you are crimping, it could very easily require specialized crimping pliers that cost several hundred dollars a pair. The vast majority of backyard mechanics (and WAY too many professional auto mechanics!) do NOT have the correct pliers and they WILL produce a marginal crimp with the pliers they do have (to tight, to loose, wrong shape, etc) almost every single time. If the crimp lasts longer than they own the vehicle, I guess it was "good enough". That would NEVER work on a critical system (or even non critical) on an aircraft.

For my vehicles, I'll take a properly done crimp connection (with adhesive heat shrink) any time. But if someone else wants to pay for the Cannon plugs, they are definitely top class!

[DeanR]

Soldering vs Crimping

Neither one for lots of stuff...Posi-Lock connectors

[jmnjrpa]

Steve,I see where your'e coming from

but, I will continue to soldier my connections simply because they give me less problems that way. BTW - when you reach the heat it takes to melt soldier you are aready on your way to a good fire with most insulations.

[crazy steve]

Here's a test you can try; put a butt splice on the ends of a piece of wire, soldering just one end. Then put the splices in a vice and bend the wire back-and-forth. I'll guarantee the soldered end will break off in 1/3 or less 'cycles'.

Actually, if you don't want to waste a couple of butt splices, here's an even easier/better test.

Pull one strand out of a piece of wire, making sure there's no nicks in it (this will skew the results). Tin one end with solder. Now, holding the tinned bit in one hand, see how many times the wire will bend at the tinned/untinned joint.

Then see how many times it takes for the other end...

'78E original owner

[crazy steve]

Ok, I'll take these in order...

Tod: No, you still are confusing electronics and electrical. Yes, solder is commonly used in the electronics industy, and on more than just circuit boards. And they don't refer to 'Aircraft Electrical', but call it 'Aircraft Electronics'. But in the electrical field, solder connections are illegal 'unless part of an approved assembly', i.e. is a factory assembled item and has a testing lab approval such as UL. If I had a current copy of the NEC, I could quote the pertinent section but what it says is ALL field connections 'shall be made by mechanical means', no exceptions. Any sort of electronic gear I ever installed (fire alarm panels, freq drives, etc) always had mechanical terminal strips for the field wires. And THE big difference between 'electronics' and 'electrical' is the circuit current and available fault currents; where most electronics operate at currents measured in milliamps, that's not the case in electrical circuits. Even a bike battery can deliver 500 short-circuit amps, and that's way more than enough to melt a solder connection. Also keep in mind that on aircraft (particularly military), there's several differences that you won't find anywhere else; these things are routinely removed and/or checked, and I'm sure that one of the checklist items is the integrity of the solder connections. They also use higher strand-count wire, so the wire is much more flexible and much less prone to vibration failure. If we had to have buildings wired and maintained to MilSpec, we'd still be using oil lamps...

Larry: Yeah, marine (particularly salt water) is a very tough environment. The big trick here is sealing the connecton. The reason I don't like solder connections is they break much easier. Like I said, heat makes the copper brittle. Here's a test you can try; put a butt splice on the ends of a piece of wire, soldering just one end. Then put the splices in a vice and bend the wire back-and-forth. I'll guarantee the soldered end will break off in 1/3 or less 'cycles'. Another issue with soldering is once you've damaged the annealing, it corrodes easier (don't ask me why, I just know it does). If I were doing a marine splice, modern 'sealing' type shrink tube should do it. On a termination where you'll still have an 'end' showing, I'd apply a bit of solder to just the exposed end (after crimping) to seal it, then do the shrink. I used to solder too, but after having multiple failures over the years (in every case, the wire broke right at the junction where the annealing was gone) I quit doing it and haven't had one go bad since with a proper crimp.

Butch: I've also been an electrician for over 30 years (third generation to boot! Not that that counts...) and soldered connections have been illegal here for longer than that. Why I don't like them in this use is covered above. But at work, I have seen some old installs that have failed though, and according the engineers I've talked to, they saw enough failures under high-current/high heat conditions that the method was outlawed. The reasoning was a slightly higher-resistance mechanical connection that has a much better chance of surviving high heat is better than a lower-resistance connection that may fail. A lot of it has to do with what kind of overcurrent protection is being used, as here nearly everything is inverse-time circuit breakers which have been known not to properly clear a short. I do know that grounding/bonding is still a bit of a 'black art', as over the years I've seen things that were required at one point become illegal and vice-versa. I'm not going to claim I know why; not even the engineers could always give a clear explanation...

The last thing to come in before I retired was 'fault current' calculations; you had to know the primary fusing at the transformer, it's KVA, and the size and length of the feeders to the service. This determined the RMS 'fault' rating of the breaker (minimum of 10K amps, up to 200K, and not to be confused with amp rating) so in a fault the breaker could clear the short without ionizing internally and maintaining the circuit. I believe you use fuses much more 'down there' and they're actually a better way to clear a problem.

'78E original owner

[b.walker5]

Steve, while I agree with your reasoning behind using uninsulated crimp joints, as a registered electrician with over 30 years in the field I'm afraid I dont quite agree with your disdain of soldered joints. In this country the use of solder in the electrical industry isnt illegal and in many cases it provides an electrically better and stronger joint than any crimp is ever going to. We have an AC multiple earthed Neutral (MEN) system with 240V single phase and 400V three phase being the common low voltage supplies. When terminating the main neutral on the Earth/Neutral bus bars in the DB solder lugs are preferred as there is less chance of a high resistance joint causing heat and potential fire. There are many other instances where solder is preferred for the same reason, including underground cable joints, and when equipotential bonding of copper water and lead waste pipes soldering is mandatory. There are, however, some guidelines around the selection and use of solder appropriate for the job in hand, i.e tin/lead and/or silver content. It's worth noting that lead waste pipes havent been used in new housing for years but are commonly encountered in older housing. Copper water pipes are still widely used and is preferred to uPVC and Poly Butynol.

In automotive applications I prefer crimped joints and terminals, and i dont use the insulated crimps 'cause theyre crap even without the insulation, but it's more out of convenience than anything else. Soldered connections in the right application are fine and provide much lower resistance than crimps, but I do accept that in areas subject to movement and vibration extra support may be needed, and it's hard to imagine doing the pickup fix with crimps.

[Larrym]

Heretics Must Burn!!

Is this a bad time to mention that I use the ABYC standards for my connections?

American Boat + Yacht Council= Crimp, solder, tinned wire, tinned connector, stress relief, glue lined shrink tubing, and labels??

You gotta see what happens to an unsoldered, store-bought, automotive BUTT splice crimp connection in less than 6 months in a marine environment. Still pretty and blue insulation on the outside.

On the inside it kinda scares me that NATURE (not man) is responsible for that color green and so much of it.

I've seen better connectivity in wire-nuts.

[trbig]

You're confusing two different fields; electronics vs electrical. Soldering is standard practice in electronics, but is illegal in electrical

You are the one confused. I was refering to the electrical connections and cannon plugs that are multi-wired ends on bomb racks, missile launchers, guns, etc, as well as other connections on just about everything. You'll have plugs that have male and female pins that you join together, but the back side of those pins will be soldered. I was not refering to circuit boards or electronics. The military uses almost exclusively SOLDERED connections to wires, not crimps. Look under a microscope, and crimping actually damages the wires. Soldering is recommended by all the suppliers who's parts are serviced that I stated as well as many others. You have to take classes to get certified to do this, but a properly tinned and soldered connection is going to be a MUCH better complete connection electrically than a crimp.

Do I crimp wires? Sure.. it's easy and fast, but no, I don't think it is the best alternative.


Tod