Originally Posted by killer22

for basic rc car stuff you need a 40 watt not 8o watt weller makes a good one.

Originally Posted by RocketRob40

OK, I'm going to weigh in because I continue to see this same thing on dozens of forums I lurk and contribute at -- and it's the same issues I see at the track as literally no one REALLY knows how to solder.
Seems simple, but it ain't -- unless you know the secrets.

1) You HAVE to have an iron with more than 40w rating unless your working on micro curcuit boards. That said, JUST getting a hotter/more powerful iron does not in itself solve the problem. Heat is bad for electronics, so just going hotter will likely make your problem worse as you'll start melting things. I recommend 40w minimum and 60w max for RC stuff. Any cooler and the heat from the tip just transfers too quickly to what you're trying to solder, and the part acts as a heat sink and sucks all the heat out of the tip of the iron so you're fighting a losing battle - and any hotter and you have to work with precision speed to keep things from getting too hot.
2) Silver solder is harder, and thus requires more heat, to get it flowing properly. And while it "might" be good for brazing and soldering jewelry, or anything else permanent, it's hardly of any use for us RCing. Just get the 40/60 or 60/40 cheap stuff - it'll do fine for what we're doing.
3) You NEED to buy flux (comes in small tins, or small squeeze tubes). Do not rely on using rosin core solder, as so many people tend to recommend it to do the trick, as it does not allow you to apply solder only where you want it. Flux is an acid, and it etches the metal you're trying to solder together and allows solder to flow and make a solid connection using the least amount of heat. Flux also keeps you from ending up with "cold solder joints" where it either beads up and drips off (as was described in the first post) or just turns into a huge glob on the parts you have sorta soldered together. As I said, flux allows the solder to flow - and by flowing I mean that it will flow like water creating a pool of solder that when cooled looks smooth and shiney.
4) Realize that you HAVE to "pre-tin" items you plan to solder together instead of just pressing the parts together, hitting them with the iron, and trying to gob solder into the joint. By pre-tinning I mean that you have to apply a bit of solder to each of the two items you plan on soldering together, AND then attempting to make your solder joint.
5) Get a spray can of motor spray, or electronics cleaner, and have it on hand when you are done (either is available in any auto parts store).

And start soldering......

a) PRE-HEAT your iron - and let it sit, heating, for maybe 5 minutes before starting work.
b) as mentioned above, take your two parts you want to solder together and apply a small amount of FLUX wherever you want solder to stick (this, of course, is after removing any insulation or oxidation that may exist). remember, a little flux goes a long way!
c) take your now pre-heated iron, and clean the tip - by whiping it with a wet paper towel or sponge (it should be shiney and silver-looking - if not, the tip needs replacing)
d) apply a small amount of solder to the tip of the iron
e) one at a time, take each item you intend to solder together and apply/trasnfer the solder from the iron tip to the part - watch as the flux starts to sizzle and the solder flows where the flux once sat (they are now officially PRE-TINNED)
f) after each pre-tinned piece has coold for a few seconds (30 or so), now take then and RE-flux each of them
g) take the two (pre-tined and re-fluxed) parts and put/lay them together in the fashion in which you want them attached to each other...
h) re-whip the tip of the iron on the sponge or wet paper towel, getting it shiney again
i) apply just the smallest amount of solder possible to the tip of the iron, and then immediately apply the tip of the iron to the two parts you intend on soldering together.
j) listen as the flux again starts to sizzle, and watch again as the solder starts to flow between the two parts and becomes one in a combined pool of bright shiney sodler. (this should take no more than 5 seconds - max)
k) remove the iron from the parts, and blow (even if you have bad breath, it will not self combust) gently on the two parts - watching as the shiney solder turns almost an aluminum color. Your parts are now soldered together.
l) grab your can of motor spray or electronics cleaner, spray some in another paper towel - and remove any grease-looking, brownish gooey stuff (this is the reconstituted flux). It should wipe off pretty easily.


TA- DA...... YOU ARE DONE.........AND YOU ARE NOW A SOLDER PRO !!!!!!!!