When solder two wires together, do you twist the wires together and then solder them, or do you overlap them and solder?

 

sorry for the crude diagram but that's the best i could think of.

 

Note the three stickies at the top of the page. I'd twist them together lengthwise and solder. Remember to heat the wire to make the solder flow. Use some shrink wrap.

JamesC

 

i read those. They say to solder wires as a best solution. I wanted to know how it would be best soldered. Your'e saying do it like in my second drawing and twist them together. Makes sense.

 

Yes. I recently did a belt to dual fan conversion (FAQ), and I used butt connectors, dielectic grease, professional crimpers, and shrink wrap. I also like Posi-lock connectors. At any rate, I'm confident that those connections will be fine.

JamesC

 

i don't like the bulkiness of butt connectors. I like everythng to tuck into the looms. I will be doing an ls1 swap so i need to get on type of my game as far as wiring goes. I have been installing stereos, amps, and such for years but always did the electrical type thing. I figured i could go back and rewire everything to get caught up on my soldering skills.

 

Each to his own. Check out the looms (with butt connectors) in the following link:

https://www.thirdgen.org/forums/faq-...electrics.html

JamesC

 

looks good!

 

Yeah man...I did mine with butt connectors because it was easy, quick, and so far efficient

 

I hate butt splices too, at least, with insulation on them. I normally use a grinder, and lightly grind one side of a butt splice to get the plastic off. Then I'll crimp it on, and heat shrink a sleeve over that. Thats the quickest, cleanest, most sealed way to make a union. If I don't have butt splices, I'll overlap the wires and solder, with no twists. Making a connection with twists, you need almost an inch, or more, of wire that gets soldered and insulated. Makes for a nasty mess, usually, so I lay em next to each other, and keep the joint under 1" total, with heat shrink. At least, up to about 12 gauge. above that, its splices, and 6 or higher, I'll crimp AND solder the splice afterwards.

This is kind of a debate between people, who argue the strenght of the connection. I feel that there should be no stress on the wires to begin with, so it makes no difference, twist to no twist, and if the wire were to happen to get pulled, I''d rather have the solder joint fail, and pull apart, rather than stretching the crap out of the wire, and needing a complete replacement.

 

overlapped looks much cleaner and shrink wrap will seal it fully against the enviornmeant as opposed to twisting.

 

It's funny that you posted this question about soldering, because I was going to make the exact same post today when I got here.

I'd also like to second James' endorsements of posi-loks. I love them! They are easy to use, make a good connection that won't come apart, weatherproof versions are available, and they can be disassembled and reassembled as often as necessary.

 

Listen to me on this one.
TWIST (preferably a Western Union style, a little lose in the middle then vary tight wraps at both ends) THEN SOLDER. Solder is NOT a good mechanical connection and should NEVER be used as one. Stress on the wires or not, vibration is all it takes. That IS the right way to do this. Heat the wire, not the solder. With the wire hot you should touch the solder to the wire, not the iron, and the heat from the wire should melt the solder. Type of solder isn't to important, but you should know the LF stuff takes more heat to melt, doesn't wet as well, and will not give the nice shiny connection the 60/40 (w/ lead) will. If using leaded solder (60/40), a connection made with the right heat will be shiny, not dull. If it's dull you had a dirty wire or too much heat. You can turn the temp down on the iron (if it adjustable) or keep the heat on the wire for a shorter time after the solder flows (if the iron isn't adjustable). You should be taking the heat off as soon as the solder has flowed well to the entire connection.

 

Clean wire and flux. That's the secret to soldering. I like the wires butted into each other with some twist, then heat shrink tubing over that. If it's a major current carrier, I use two layers of the wrap. One thing that stands out to me when I look at a car is the wiring, if it's all messed up the whole car looks bad. Good connections, neat placement, hide what you can, use wire looms when necessary. Amazes me how the factory can run a hundred wires and have it look so neat.

 

THere is no way a clean solder connection will break from vibrations. It doesn't hurt to twist them but I don't waste my time doing so.

 

WHAT! It happens ALL the time. You're flat out wrong in this one. And companies don't spend thousands of dollars on shake table time. And there no need for shake tables ether. OK...

 

Yeah, there is a need for shake tables, for other reasons. But properly dressed and bundled together with other wires in a harness, a lap solder joint that is heat shrinked will live a long and happy life. Sure, if you are on a launch pad, or maybe part of a jack hammer, it could be a problem. But for the vibrations a wire in a car might see, I just don't see it happening. I can count on one hand (with no fingers) how many times one of the joints I prepped this way have failed.

actually, I have had one failure. But, the joint failed (due to someone yanking on a wire without knowing it was still connected), and I just had to resolder and get on my way. If it had been twisted and made more 'secure', I would have had to replace the whole wire, which would have been more downtime, plus unavailable connector crimps, etc.

sorry, I hate to argue, but I just have never seen real life data that has ever proven that wires need to be soldered with twist in normal applications.

 

I must be doing something right then. Never had a solder connection break on the THOUSANDS of electronics I've built or repaired which have been in everything from cars to guitars.

 

So you "repair" things and have never seen bad solder connections? How did you think they happened? Ever notice that 9 time out of 10 it's on a larger part (filter cap, coil, ...)? Ever wander why? Vitiation. And just because you got away with it DOESN'T mean it's the right way to do things. Ever do R&D work? Ever spend 8 hours watching a shake table? Ever gone through any solder certification training or tests? There is NOT ONE of them would say that this is anything but the wrong way to solder two wire together. There are cases where you have no choice but to 'lay' the wires, but they are rare and any time you can make a good mechanical connection you should.

 

Maybe a real word story would help. One of my first night jobs was for a small run manufacturing shop. If someplace like Motorola need a small run of a PCB (auto power switch for remote cell locations), it may be more cost effective to have a small run shop make them. Opposed to Motorola setting everything up and making a 200 pc run they gave use the specs and we made it for them. We got work like that. Any way, one of the things we made was temp sensors used in truck reefer units. A small 1’ by 3’ PCB with two wires, one black, one yellow, tined ends, a resistor, and a thermistor, a small hole 0.5 inches from the top. After a couple of mouth the customer called back saying they where all going bad. They sent ten of them back and they all had bad connection under the thermistor. After a lot of back and forth they agreed that there instructions should have included gluing the thermister leads to the PCB. We did the tests (to convince then it WAS there design that had the problem). 100 of them NOT glued, 100 of them glued. After driving up to NY and sitting in front of the shake table all day, (so much for the ‘night job’) just under half of the NOT glued one had failed. NOT ONE OF THE GLUED ONES FAILED.
Open up 90% of the car audio equipment and look at the filter caps, the filter coils, or any of the larger parts. See how they all have this white glue holding then to the PCB? What’s that for? To keep the part from vibrating separate from the PCB (helping hold them in place during the manufacturing process is nice to).
Some other real word example I just thought of. Pioneer had horrible problems with bad solder connections under the white Molex style plugs they used. They stop the problem by making the holes in the circuit boards smaller. This made the harness almost a press-fit into the PCB helping the mechanical connection, less mechanical stress on the solder connections. No more bad solder connections. JVC HUs that have the older single sided PCBs use larger diameter holes in the PCB for the power supply IC and have problems with bad solder connection here. Newer Duel layer PCBs use smaller (almost to the point of a press fit with leads) holes at the power supply ICs. They also bend the leads of the power supply ICs so they press out against the holes. No more bad solder connections. It’s common to see bad solder connection at the antenna jack. That’s why some manufactures ‘twist’ that lead to hold it tight to the PCB. You don’t see bad connections under these ant. jacks.
Not making a good mechanical connection doesn’t mean you will have problems, but making a good mechanical connection (among other thing like clean connections) help mean you will not have problems.
I removed some things out of this post. I don’t want to come off as attaching here. But there is a right way and wrong way. If someone takes some short cuts on there car, fine, I have. But before someone does, they should under stand how far short they can cut, or are willing to cut. And they sure should understand the possible pit falls.

 

How i been doing it for years: Tin both ends of wire with solder. Apply heat shrink to once side of the wire, keeping it away from the heat from the soldering iron....lay tinned wires next to each other and heat up joint...solder will flow now that they are tinned and make a GREAT connection...Place heat shrink over newly soldered joint and heat up. Walla... never had a failure yet...and I been at Tronics for 30 years...

 

Can one of your soldering experts post a pic or two of what a professional quality soldering and shrinkwrap job looks like? I have soldered in the past, and was doing it yesterday while repairing my starter wiring, but for some reason my soldered connections come out very messy looking. Large amounts of solder that make a bulge where the wires meet, which then leads to a sloppy looking heatshrink job etc. I'd like to get a lot better at this. Don't know if I am applying too much solder or what...?

 

for stuff like starter wires, I would use a butt splice with no jacket, crimp, then flow a LITTLE solder, then heat shrink.

the blobs of solder usually indicate too much solder, not enough heat, and not enough wetting (flux). What I find to work nice, is if I have a joint that has too much solder, and joint is a dull color, is to add more solder, so that the flux in the core will help wet out the joint, and kind of flick off the excess solder. should wet out and the surface tension should leave just a light layer of solder.

 

^^^ What he said.
If you're using stranded wire the solder connection should be shiny and you should be able see the individual strands through the soldered connection. I've got a pic of a ground loop that shows a good solder connection I'll see if I can dig it up.
A couple things I'll add. If the connection is not wetting well and has a dull color it is ether a dirty connection or to hot (heat is more the dull look). If you're not using a temp controlled iron take a wet sponge out with you to wipe the tip through. This will help keep the tip of the iron clean and will bring the temps down a bit. Clean clean clean. Heat the wire until the wire melts the solder, NOT the iron. Then as soon as the solder flows where needed take the heat away. Using greasy fingers to twist the wire (like working around the start) can make it hard to get a good clean connection. Grab some solder flux. The liquid stuff is nice but the past you get for working with pipes will get the job done too. Just a little goes a long way. But really a good quality solder should give you the flux you need. Unless your working with funky wires. If you add too much solder add some fresh and 'wick' it off, as was said.