I work for a municipality (a city) fleet department, and we are always having to make our own power and ground connections for everything on our city vehicles. From the amber light bars that you see on non-emergency vehicles to the full emergency setups on police and fire vehicles, we do it all. There are some very valid comments on both sides of this topic, and it's one that is debated in the professional world quite often. Automotive manufacturers have more quality control over their crimp connections than what the rest of us do not. If 100 of us on this form crimped the same 12ga ring terminal on the same 12ga sized wire, there would be a lot of variation in the outcome of our crimps. Some would crimp the connectors at the split section of the terminal, some would not. Some might crimp high on the terminal and some would crimp low. Manufacturers don't normally have humans making their connections unless we are having to go into a job that requires a repair to a terminal end.
How do the automotive manufacturers take care of the quality control on their technicians when a repair has to be made? Simply put, they train them in the ways that "they" would like connections to be repaired. I've been through every AC Delco class there is when it comes to automotive electronics, and if you know anything about AC Delco then you'll know they're brand name is pretty synonymous with GM. AC Delco preaches both methods of repairs; crimping and soldering. Their technicians have to pass a course in order to dive into their wiring repairs, and they're taught how to make proper connections to both GM and AC Delco's specifications. Not only are they taught how to preform crimps correctly, but they are also given the perfect crimping tools to make them. Delco has a kit that can be bought that has every type of GM electrical terminal there is in it with their crimp tool and such all in it, and it'll run about $1200 or so (last I heard anyhow); there's a lot of stuff in there. That being said, 100 students from Delco or GM's schooling program will make their crimp connections differently and with more uniformity than 100 random people from this board would. Precision tools used by manufacturer technicians apply a lot more exact and precise pressure to their wires than a $20 or so dollar crimp tool from Autozone or even Radio Shack would. Manufacturers don't want to pay for "come-back" concerns, which would simply be a job that returns for the same issue that it originally came in for in the first place; quality control is nice.
These schools also teach soldering methods however as well, and in the professional aftermarket world, soldering is more widely used (as you might have noticed by the way this thread reads). I've dealt with both great and poor wiring in my line of work. In police cars, there are hundreds of wires going to light bars, flashers, LED options, radios, etc. More often than not, if our shop wires a car up from the start and it comes in for a concern, a specific part or something else is to blame other than the wiring because everything is soldered. Crimp connections installed by installation centers bundle up and bends with side loading are placed on the pinched connections inside terminals which cause breaks in circuits. Most non-manufacturer crimps tend to be poor, and too many bundled in one area will stress wires right out of their terminals that will lead to some option not working properly. Many crimps work for a while, but if a controller has to be pulled a few times and then reinstalled, those connections are put in jeopardy of wiggling out of place.
When a connection is soldered, it's pretty dang solid. For us, wires don't pull out of their spade or ring terminals; ever. Try crimping a terminal onto a wire and then pulling on both the terminal and the wire itself; where do you think the connection will break? If a terminal is soldered and the connection is so solid that its stiff, the same pull test will result in MUCH higher torque numbers before anything happens, and your not likely to have the terminal break off of the wire (unless it's of some cheap quality). On average, soldered connections are more stable than crimped. Aftermarket wiring is accessed more often than non aftermarket. Just like with the manufacturers, if a connection is solid the first time then it's likely we won't have a come back concern for something we did on that end of the spectrum.
How does this relate to the audio world? In many ways actually. The gentleman with the electronics shop is smart to do business the way he does with the soldering option. Repeat customers need to be coming back for new options, not repairs to old ones. One or two of those are likely to have you lose a customer instead, and that's not good on many levels. Have you ever had a crimp connection come lose? Ever seen a fuse blow over a crimp connection? Because I have, and we all have to use heavy wiring to our amps and such. Try applying Ohms Law to a poor crimp on an 8ga wire that is pulling 30-amps on one end and say 50-amps on another. Pushing too much power through a small connection creates resistance, and heat build up on those strands of wire can cause bad problems. Proper soldering has its place. If you remove and replace your head unit or amp too many times due to adding options or whatever, you might get lucky and never have an issue with your crimp connections over ANY vehicle you ever own. I happen to know that my soldered connections will NEVER fail by having a wire come free from a connection that I put together, and that to me is worth the peace of mind. To tell someone that solders connections (like I do for everything) that they are wrong is maybe not so much wrong for their opinion, but more so misinformed.
http://www.denlorstools.com/home/dt1/page_561/blazer_original_self_igniting_mini_butane_torch.html
I use a torch much like the one in the link above for my heavy gage connections. If I'm trying to place say a 4, 2 or whatever gauge wire into say a brass ring terminal or maybe even into a main battery terminal, this is how I do it. I like to use a pair of vise grips and clamp onto the larger terminal in the smallest area that I can, yet hold a good grip on it. I'll weight the vise grips down with something, and make sure that the cup of the terminal is sticking straight up for me to fill with solder. Rosin Core Solder is the only proper solder for 12V automotive use, and if I'm not using rolled spools then I'm using solder pellets with the flux-goo already inside the pellet itself. If you heat the terminal up, the heat transfer will go into the tip of the vise grips which will take some of the heat energy away from from the terminal, so don't clamp too much of it with them or it'll take forever to heat up. Once at a proper temp., the solder will melt and become a liquid in the cup of the terminal, and I always fill it to the top. Once the solder is liquid, force the cable rather quickly into the terminal, and your cooling procedure will begin to fuse the cable with the terminal itself. Sometimes you need more solder as the wire might not quite fuse too well with the terminal if you don't, so keep heating the terminal and feed some spooled solder in till everything is like you want it. If you do this, I can promise that the connection, if soldered correctly will be SOLID. Use some good heat shrink with some sealer in it, and no corrosion will get to your new cable.
Irons work for smaller stuff, and I use a cordless butane torch for that as well. Soldering takes a bit longer than crimping, but the connection will last a lifetime. You're more than welcome to crimp your connections and or strip, twist and tape them. To tell someone however that solders their connections that they are wrong really isn't going to go very far in an argument. There's a time and a place for everything, and though I understand the needs to crimp (I many times will solder crimped connections), I will always choose to properly select my wire and fuse sizes, and they will all by soldered and heat shrunk together.
Dustin
really hard while it was screwed down to a workbench) the wire out of the terminal JUST CRIMPED and not soldered. The solder is just for good measure and peace of mind. The crimp anvil works AWESOME for up to a bit larger than 4/0, and effective for 10 gauge.
