what about lead free solder? any good at all?
Not the best IME. The leaded stuff has a much lower melting point, so it's easier to avoid melting the cable insulation etc. In this respect it's also best to use a bigger tip on the iron - you want to get the joint hot quick before the heat starts spreading down the cable.
Like DevilJaw said, use 63/37 percent not 60/40 - the tin and lead will melt and solidify at the same temp, so it places less internal strain on the joint as it cools from the expansion ratios.
The stuff with a little silver content is said to make a bit stronger joint, but I don't use 'cos I'm paranoid over the "red plague" issue (silver can promote oxidation of the copper conductor beneath in conditions of high humidity).
For the flux...don't use stuff from the hardware store, the plumber's flux they sell is too aggressive for electronics. I've used a no-clean flux pen which works very well for me. Roisin is also a good flux, although produces particularly irritant vapour.
Audiophile nutters also claim different solder recipes sound different, but whatever...
Also, never solder the wire and then trim off the excess - always trim first and ensure that the exposed copper is completely covered by solder, otherwise it will oxidise over time.
