Quoted from donjagra:
I just bought a sweet 30 watt setup at the local radio shack closeout for $5.
20150306_203405.jpg (Click image to enlarge)
Wow - that looks like the exact soldering iron kit I used to launch my electronics hobby (and later electrical engineering career) 41 years ago! I guess some things really do never change...
That said, it's a pretty crappy iron (though it's still a lot better than the massive soldering gun some people try to use). I'd get one of the soldering stations mentioned above if I was going to do a lot of soldering. Better tips, better temp control, better grip, less interference from power cord, etc.
I've always preferred the high temp ranges - get in and out quickly. But mid-low is probably better for pinball - it's too easy to melt the plastic on a coil lug if you have to spend more time than you expected heating it.
Heat the two (or more) elements you're trying to solder together, apply the solder to those elements, NOT the soldering iron* (you want to make sure the wires/pads are hot enough to melt the solder), and then pull the soldering iron away and make sure the elements being soldered don't move while they're cooling - that's 99% of good soldering.
*after you get good you can cheat on this part.
If you can, practice on some wires/junk pcbs before you work on your machines. Good luck and have fun!