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Discussion Starter #1
I'm doing a wire tuck on my car while the engine is out and can't decide. Everyone seems to be either or. I've never soldered before, but I'm sure I'd learn quick. The problem is butt connectors seem to stand up to vibrations better, but soldering seems way more sturdy. Advice greatly appreciated.

:beer :
 

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Discussion Starter #4
solder and heat shrink. much better connection. tin all your wires before you solder them together and youll have no issues.

or you could do both?
http://www.fastenal.com/web/products/detail.ex?sku=0710574&ucst=t
Damn those are pricey! After some more thought it looks like I'll going with solder. Butt connectors never seemed right to me to begin with; in fact I was amazed anyone recommended them in the first place.

Any advice on what kind of solder to use? Some have said lead free, but it's easier to make a good connection with a good mixed of tin and lead right? There's too much damn solder out there for me to decide on my own lol. Also, advice on a good iron would be helpful too. From what I gather, I don't have to worry about it getting too hot, but a good solid unit that will stay a consistent temperature for hours at a time would be ideal.

Thanks guys :beer:
 

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Just go to radioshack and pick up a 40watt iron and some rosin core solder. Rosin core has flux in the solder, that's what draws the solder to the copper wire. You're only joining wires, the type of solder you use isn't very important. I think 60/40 is what radioshack generally stocks and it works fine. I like to use the thinner solder, it's easier to control how much solder you use. Using too much solder can leave a sharp solder joint that can break through heat shrink tubing. Grab so me flux paste too, if you run into any wires that are slightly corroded or heavier gauge wire extra flux will help it stick.

I personally do not tin the wires, only the tip of the iron. Tinned wires are stiff, and you can't twist them together. It's hard to explain but you wanna twist the wires together, but not the way you would if you were using a wirenut, like this "- - " not like this "_|_". Remember, heat the wires with the tip of the iron and let the solder melt into the wire. Don't melt the solder with the tip itself.
 

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Solder your wire splices, you'll be far happier in the long run.
Old timers will remember that crimp on splices were designed to be temporary, but we use them as permanent repairs now.
If you must use a crimp connector, tin the ends of the wire first-it will give the connector a better bite into the wire.
The fastenal (probably made by someone else like Thomas & Betts) are good, but not as good as a properly soldered and shrink tubed connection, and they're way more expensive. I acquired some when I worked for Barnes group, and they're brilliant. Just too expensive for me.
When you buy shrink tubing, try to buy the adhesive lined stuff-way better.
 

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Discussion Starter #7
Thanks i actually have gone with solder and I'm glad I did. Everything about it seems better than the alternative and no, I would not feel right dropping all that cash on those fancy butt connectors, not with all the damn wires that are in a mk4! Lol
 

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There are a lot of crimp downers here. I use them for quite a few things, often and have never had an issue. I use only non insulated, seamless, crimp barrels and use a ratcheting crimp tool to ensure that they are all as consistent as possible. All crimps are double shrunk to protect the splice. I would trust my crimps over the solder joints you guys are talking about with the twisted wires!!

The solder joints I do make, I take the time to tin both sides and make sure the wires are overlapping around 1/4" and make sure I add solder to the joint and not just reheat the tinning. Then they get double shrunk for protection and strain relief.

You won't have a problem with either if done right. There are a few things I have wired that ended up getting both crimped and soldered, but that is another story altogether...
 

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.......... I would trust my crimps over the solder joints you guys are talking about with the twisted wires!!

...........The solder joints I do make, I take the time to tin both sides and make sure the wires are overlapping around 1/4" and make sure I add solder to the joint and not just reheat the tinning..
Not sure why you think butting 2 tinned wires together is better than twisting them together, that's only as strong as the solder sitting in between 2 wires. It doesn't really matter how strong your crimp connectors are when a twisted solder joint is stronger than the wire itself.

The correct way to solder 2 wires together (not my pics)..........

 

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FV-QR

For what I was doing professionally quite a few years ago, we were not allowed to make splices like that as the joint *needed* to be tinned first. It's quite common and part of the milspec for any wire to terminal assembly, though I can't find it listed anywhere with free access.

In any case, if you were to tensile test that joint, vs 'my' lap joint the wire itself would fail before the joint in both cases as long as the joint was done with proper technique.
 

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For what I was doing professionally quite a few years ago, we were not allowed to make splices like that as the joint *needed* to be tinned first. It's quite common and part of the milspec for any wire to terminal assembly, though I can't find it listed anywhere with free access.

In any case, if you were to tensile test that joint, vs 'my' lap joint the wire itself would fail before the joint in both cases as long as the joint was done with proper technique.
Specifications and whatnot are designed to lessen the amount of "failures", and there's plenty of different ways for something to fail. I don't know what type of work you were doing as most manufacturing doesn't allow splices in wires period, but they may for example specify all wires to be tinned and lap soldered because there's less of a chance for a sharp wire end to pierce through heat shrink tubing that way. Or the wire may enclosed in a conduit of some sort and that sort of splice is smaller.

Kind of the same reason that all residential splices must be made in a box with wirenuts. In that specific environment it's the method with the least amount of failures. That doesn't mean it's the "best" or "strongest" splice you can make, but in that case where splices are always bade in a box with strain relief strength is totally irrelevent.

As far as tensile testing the splice and the wire itself being stronger, that's totally up to the wire size and strand count. if we're talking about 18awg then I wouldn't disagree with you, but if you're talking about say 12awg well......But that's all upto engineers who spec all of that stuff out, to the average Joe who's doing some general wiring in his car it's a little different.
 

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Discussion Starter #12
application when determining what is best; it's clear soldering is better for some, while butt connectors are better for others. And we're talking about wires in cars, specifically in engine bays. :thumbup:

When it comes down to it, I think if you're doing this professionally, odds are you're being told to use butt connectors because of a variety of reasons. And the point on tinning the wires first is something I never thought about. Someone did recommend that to me, but I found it was easier/ safer not to tin them.
 

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Discussion Starter #13
Something I found flipping around someone elses build FYI:

The only way a solder joint works is if the solder coats each strand and that then bonds it together. You have no copper connection then and resistance is higher. This is a fact not a matter of opinion that can be argued.

Most people have no clue how to properly solder or crimp but it is much easier to fake a mediocre solder joint then it is to fake a good crimp. You need the right type of connectors and tools to do the job right.


Twisting the wires actually introduces a HUGE stress point right at the solder joint which is where and why most fail. Even if heat shrinked the solder joint is the point of any stress on the wire. With a proper crimp the wires point of connection to the crimp itself is not the point of stress, it is protected within the hard metal tube limiting movement at the connection point then a heat shrunk and sealed tube adds additional flex far away from the actual connection.



Again this is exactly why the FAA REQUIRES all crimped connections and no solder connections, they have proven to be more reliable and have less resistance.
 

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Discussion Starter #17
Vw has a service training book on why to crimp and not solder. It was the whole reason they required the "BIG GREY BOX" of electrical wire ends, and yellow wire and yellow tape. I actually love the heat shrink crimp connectors.
But they never did a wire tuck ;) of I didn't one sensor or something, sure why not, butt connectors all the way, but every damn wire in the bay, solder all the way
 

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I've repaired dozens of wiring jobs and I'd never use crimped connectors.

I can't even count the number of times I've found broken , frayed, twisted, or corroded connections where spade, butt, or crimped connections are. They let water and air in so easily and then you end up with rotted wires all through the loom.

Solder every time and properly heat shink wrapped and then braided is the only way for me when I'm doing looms.
Then again, I consider my solder joints to be of a very high standard. I've seen some incredible hack job by guys who solder with a blowtorch and plumbing solder. It's just as bad as twisting the wires together and taping them up.
 

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Crimping can be done well, I use uninsulated crimp connectors with a good ratcheting crimper, then seal the joint with adhesive lined heat shrink. I solder sometimes too, I tin the wires and use the proper amount of heat, then cover the joint with adhesive lined heat shrink. Really either is fine if done properly. The red/blue/yellow insulated crimp connectors crimped with pliers have given crimping a bad name. If your crimper cost less than $60, you should reconsider your method.

Solder isn't used in some aircraft and race cars because it gets brittle and doesn't heat cycle well. It can crack from vibrations or even overheat and re-melt in certain areas of the engine compartment.
 

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Crimp > Solder. When you're working on a VEHICLE that causes vibrations and experiences many different environments the last thing you want to do is heat up and weaken your wires with a soldering iron. A soldered connection is only proper if the wire will never, ever, move and will not experience hot, cold, hot, cold, etc.

Its a very common misconception that soldered connections are better than crimped. As long as you use the proper butt connector and heat shrink and crimping tool you're golden. A$$ connectors you find at local parts stores can get ghetto and if you crimp them with pliers or something stupid you're just retarded and deserve to have connection fail on you.
 
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