Soldering and Crimps - Good Tools Required.
If you are going to do high performance soldering you need a real, temperature controlled soldering iron with interchangable tips. Good soldering is a skill that is easy enough to master but does take proper tools. Poor connections are the undisputed number one source of problems in electical/electronic systems and soldered connections are no exception.
I've done some field repair with a portable iron (Wahl rechargable, not butane) but its no substitute for a good corded iron. Here's why. When you solder, you first want to have a good mechanical connection.. twisted wires, hooked wires through a terminal etc. Then you want to apply heat to one side of the connection and solder to the OTHER side. When the connection gets hot enough at the solder end, its hot enough throughout and the solder will melt and wick its way through the twisted wires etc and UNITE the wires and terminal et al. The good mechanical connection ensures that the wires will not wiggle while the solder is cooling and you'll get a fine shiny lifetime connneciton.
The secret to successful soldering is heat flow and temperature control. You want to heat up the joint quickly, apply solder and remove the heat as soon as possible to keep from overheating the joint. If your iron applies too much heat, you'll melt wire insulation, plastic housings etc. If it applies too little heat, you'll get a 'cold' joint and you can also melt things as the whole system heats up waiting for the solder to melt. Either way, its bad news.
IMHO, the only way to go for all but the occasional job is a good quality, corded temperature controlled iron with a variety of tips. I have several Weller WTCPN stations with a variety of 700 degree tips, small conicals for small things and the bigger 'screwdriver' tips for large joints. The temperature control idles the tip at 700 degrees when its in the stand then applies LOTS of localized heat when needed. The joint gets soldered and the iron removed before the heat can propagate up the wire, melt insulation etc. Its the only way to go. Like Paul, I'm sure I could get a great joint from just about anything that gets hot (I've done silver soldering with a cutting torch-'nother story) but also like Paul, have had real training (from NASA even!
.. before Skylab..
) But I always prefer to use appropriate tools for the job. You don't bang rivets with a hammer, why solder with a 'hot thing'?
If its a matter of learning to solder, relax. Its not real hard to learn but make it easy on yourself and get a good iron and use quality solder too. Along with Weller, HAIKO irons are supposed to be very good and a bit more sophisticated. My basic Weller WTCPN will set you back about $120.00. HAIKO about the same. Like any good tool, its a good investment. Buy extra tips in various sizes. Stick with 700 degrees, for Weller its controlled by the tip, for HAIKO, I think they have a control knob..
For solder, Kester or Ersin Multicore is great. Alpha's OK, too. 60/40 or 63/37 will do. 1/16" dia is fine. Don't buy the cheap stuff and always use rosin core.
To learn, practice. Good joints have the solder shiny and forming a smoothly graduated slope between the parts. If the joint is rounded like a bubble, it hasn't joined or you've used too much solder. If it looks frosty, its probably because the wires moved while it cooled. The solder is fractured and needs to be reheated. After a few joints, the excess rosin on the tip will bubble to the top and show as a dark residue left on the joint. Minimize this by cleaning the tip on the wet sponge provided with your expensive iron before each joint. Wiping the tip on the cool sponge will also cool it enough to kick in the temp control, making the tip piping hot when it hits the joint!
Big Soldering Secret: After cleaning the tip, apply a touch of solder to it. This will make a liquid film on the tip that will flow onto the joint when you touch it and make a heat path from the tip to the joint. The joint will heat rapidly and be ready to accept solder long before adjacent parts get too hot.
Second Big Soldering Secret: Use the right tip. A 3/16" Weller flatted conical tip is ideal for most solder-the-wire stuff. Bigger terminals, say 1/4" tabs to a brass grounding plate need to put more heat at the joint so one of the big flat 'screwdriver' tips is called for. Pick the right tip, and the temperature controlled iron will apply just the right amount of heat to get the joint just right to solder. Can't do that with anything but a temp controlled rig.
By now, the value of a temperature controlled iron is apparent. Wipe it on the sponge to clean the tip. Tip gets cool. Iron fires up and heats tip big time just in time to apply wetting solder. Apply big-hot tip to joint. Heat flows fast. Solder on other side flows and unites joint. Iron is removed before other stuff gets too hot. Solder cools to a shiny surface. Great Job!
Soldering rocking now? OK!
About the crimp vs solder thing, its not a thing. Its two different things. If you have to solder a crimped terminal you haven't crimped it right. If you can't crimp, solder. Never tin wires with solder before crimping (won't crimp right) and never solder after crimping (makes stress points).
A properly crimped terminal is gas-tight and every bit as secure as a soldered one. But 'properly' means using the right tool for the terminal. Paul indicated he spent big bux on crimp tools. He's not kidding. Crimp terminals and tooling are designed as systems that are matched to one another and a serious amount of engineering goes into each one.
Really.. A former neighbor used his Phd in mechanical engineering to design crimp and IDC terminations for 3M. When, over some BBQ and wine, I ventured that with that education, maybe he should be doing something like.. oh.. maybe .. fly the Space Shuttle.. he lit into me with how much goes into a termination, ductility of copper, pressure points and material flow and a bunch of other stuff, mostly unprintable. But, the lesson I took from the exchange, other than don't overserve mechanical engineers, was that the ol' Radio Shack wil-fit crimpers had to go.
And as I am sure Paul would agree, when you crimp that 30 cent DB-25 pin with your $150.00 AMP ProCrimper II, when you hear the wonderful *snick* of the ratchet crimp going home and you view the perfectly crimped, gas-tight connection you have just made, even under a 100X microscope, you'll undoubtly say..
$150.00!! for just one type of connection??
Yup! Sorry!
As long as you are at it, multiply that by how many other connector series you use. Years and years of experience would have me exhorting you to pay the freight. Some would say I've been bitten too often. Maybe. But before you dismiss my ravings, reread Paul's views about expensive crimpers.
Then pony up.
Because Paul
does fly the Shuttle.
