Soldering Tutorial:

[suspendedHatch]

In these photos I'm changing the plug connector and replacing a missing bulb socket on a tailight I got at the junkyard. That's not the point though. The point here is to show you guys how to solder. I see a lot of crap wiring out there. It's scary, it's just bad and there's no reason for it. Soldering doesn't require any expensive equipment or any great skill. It takes less than $50 for tools and supplies and maybe a couple hours practice.

Tools Required:
*100 Watt soldering "gun" from Sears or Radio Shack $30
**wire stripper from Harbor Freight $10

Supplies
spool of .032 solder
electric "black" tape
***spool of 18 gauge stranded wire
inline fuse holder (depending on what you're trying to make)
split loom aka corrugated tubing
small zip ties

*Don't get that "cold solder" crap. The name itself is reason enough. A "cold" solder is a bad solder joint. Don't get a low wattage pencil shaped soldering iron (unless its a butane iron). Get yourself a Craftsman 100/140 watt gun shaped soldering iron with the little light on the end (or similar). The quality of the soldering iron and solder will determine the quality of the job and whether you ever learn to solder successfully.

**The quick strip tools are the most desirable (orange handles), however, I often rely on my little cutting tool (blue handles). I got this from the Snap On guy, although it is not made by Snap On. If you use this tool, squeeze the wire until you feel the tool bite into the insulation, then push the tool upward with the thumb on the same hand that is bracing the wire (see photo). I recommend against the most common type of wire strippers.

*** 18 gauge works for most things we do to our cars, but use your own discretion. Starter/alternator wires are 10 gauge. If you want to upgrade your ignition/fuel/lighting wiring you might want to use 16 gauge, but no thicker than 14 gauge.

Steps:
Wash your hands. You want to reduce the amount of human contaminants in the joint to prevent corrosion.

Strip back the insulation on each of the wires half an inch. Twist the wires together. Don't use the traditional method of twisting them together. You want the twist inline with the wire. Make sure there are no points sticking up. Roll the wires together like a joint (pun intended). Hey, this is how I was taught, okay?!

Heat up the soldering gun and then touch the solder to the tip and get a thin layer of solder at the point. Lay the twisted portion of the wires on top of the soldering point, and then wait a few seconds for the wire to heat up. Touch the solder to the wire strands (not the soldering gun). You'll notice that the wire itself liquifies the solder and it soaks between the strands. You want to lightly paint the entire joint this way. The strands need to remain visible. You don't want a big goober on top of the wire. Less is more. Don't overheat the joint. If the insulation starts to boil off the wires, you're overheating it. Work faster.

Wrap the joints in electric tape. Electric tape is the only tape that will work. Stretch the tape slightly when wrapping it up. Squeeze it between your fingers to make sure a strand isn't poking through. In most cases you'll want to bundle your wires with tape or split loom, then secure them with zip ties.

Now get out there and redo all your shitty wiring. Then, once you have some practice under your belt, go out and make some money building harnesses and doing conversions for people.

 

[phunky.buddha]

Add flux.
Lap joints are the strongest, even compared to twisting wires together.
Use shrink wrap when possible, not tape.
Stagger your splices when you have a bunch- that keeps your bundle thickness down.

 

[suspendedHatch]

Actually no, you don't want to add flux. Everything you need is already mixed into the solder.

Shrink tubing I generally reserve for when I'm using non-insulated butt connectors. I think I'll do a second thread on how to crimp wires the right way.

 

[posol]

Put it all together in a "wiring" article, and you have a nice solid submission

 

[phunky.buddha]

Flux is always good. It promotes a good clean joint and makes sure your solder flows well.

I guess I should just start posting up my military spec class 3 solder manuals... but the company wouldn't like that too much.

 

[suspendedHatch]

Thanks for your responses. I appreciate that you're trying to strengthen my original post. My tutorial covers the type of stuff we do to our cars. Not the "best" as in failproof overkill, but "best" as in overall cheapest/quickest/easiest for everyday installations that you can expect to outlast the vehicle.

In my line of work, I am responsible to warranty all of my installations for the lifetime of the vehicle. I've never had an R&R caused by a bad solder joint. Use this tutorial as a launching point, and develop your own technique from there.

 

[GSRCRXsi]

i also second the notion of heat shrink. so much cleaner. both on the eyes and the hands. i hate getting that sticky black shit all over my hands from the tape. especially when i am redoing some wiring and ddealing with old tape. i prefer to leave the tape to hold the loom together.

not sure what mike means by lap joint, ill have to see a pic, but when i do wiring, i always fray out both wires, interlock them, then twist. always comes out clean and pretty easy.

 

[phunky.buddha]

Thanks for your responses. I appreciate that you're trying to strengthen my original post. My tutorial covers the type of stuff we do to our cars. Not the "best" as in failproof overkill, but "best" as in overall cheapest/quickest/easiest for everyday installations that you can expect to outlast the vehicle.

In my line of work, I am responsible to warranty all of my installations for the lifetime of the vehicle. I've never had an R&R caused by a bad solder joint. Use this tutorial as a launching point, and develop your own technique from there.

That's cool man. Good solder joints that most car installers do would typically be classified as "class 1" (lowest) in the IPC and J standards, but are more than sufficient for car stereo stuff that doesn't experience much stress. Everything that I work on now has to meet or exceed class 3 (highest rating) no matter what. Stuff that's typically class 3 are items that are either mission critical or life critical and can't fail under any circumstances, no matter what- like pacemakers, hospital life support systems, airplane controls etc. It would really suck ass for a battalion of soldiers if an intercept missile didn't work to kill an incoming hostile projectile just because a solder joint was bad. We're really really really picky.

i also second the notion of heat shrink. so much cleaner. both on the eyes and the hands. i hate getting that sticky black shit all over my hands from the tape. especially when i am redoing some wiring and ddealing with old tape. i prefer to leave the tape to hold the loom together.

not sure what mike means by lap joint, ill have to see a pic, but when i do wiring, i always fray out both wires, interlock them, then twist. always comes out clean and pretty easy.

Yeah, I use heat shrink whenever possible in my own stuff, and it's all we use at work.

Mike, I'll pull some pages from the IPC manuals and show you what I mean, and throw them up here for reference for everyone else too.

A lap joint is basically just laying two wires on top of each other. The wires will come together like two parallel lines, and you just flow solder between and all around them. With the wires properly tinned and not frayed, this is one of the strongest solder connections possible for putting two wires together end to end. Another variation is to tin your wires, then make two 180 degree J hooks out of the two wires, then hook them together before flowing solder to join them.

 

[suspendedHatch]

Yeah the main idea was to write a relevant and simple soldering tutorial to fit the site. A military grade soldering tutorial would scare the average DIYer from even trying and it doesn't fit the context here. Anyone that does that level of wiring would balk at this tutorial, the same way a brain surgeon would balk at a school nurse. But you don't need a brain surgeon to get you back out on the playground for recess. Okay, I'll let this stupid analogy die now.

Heat shrink is great for some things but it doesn't always work that great with solder. The radiant heat from the soldering iron shrinks the tubing prematurely. Heat shrink requires more tools, more supplies, and more thought. If you really want to see heat shrink, look at my crimping tutorial. It works great for non-insulated crimps where you already have a box of supplies spread out. If I'm going to go do a quick fix for somebody, I'm bringing my butane soldering iron, some solder wrapped around my finger, and a roll of tape. Heat shrink and flux is just making it more complicated than it needs to be. How much do you need to improve on a connection that I guarantee you will outlast the vehicle? And GOOD tape doesn't have the problems you describe. If you're wiring near hot or wet surfaces, you should take that into account and not blame the tape. Don't buy your tape at Walmart or even Radio Shack.

My focus is actually car security. Car alarms are pretty sensitive to intermittent and weak connections. T-tap connections may work initially but those alarms tend to burn out within a year or two. I do some mpfi conversions, engine swap conversions, OBD conversions, gauge wiring, engine management wiring, and general electronic repair. All this is a bit more involved than car audio, although nowhere near military wiring, which is something my dad did for a long ass time.

 

[phunky.buddha]

Agreed on the military spec stuff... but if that's the type of soldering that you're used to, it doesn't take any more time to make a better joint with the same tools that you use in a stereo shop.

Good article nonetheless.

I disagree with you a bit on the heat shrink. I do buy the "correct" type of electrical tape, but I still hate using it. I use heat shrink wherever possible. I just slide it up the wire far enough to not shrink from the ambient heat, then shrink it into place with a cigarette lighter. If it wasn't for heat shrink, I wouldn't ever buy a lighter. If the heat shrink can't be moved far enough away from the joint before soldering, I just go in with low heat or a sink clamped to the wire to keep the heat from reaching the heat shrink. A simple pair of pliers grasping the wire in between the joint and the heat shrink is enough to absorb sufficient heat not to shrink the tubing.



Radio Shack = Radio Crap