I have to confess, I'm a lousy solderer, my hands tremble, and I'm often too anxious to get the job done and leave bad joints. To make the job easier, I used on my latest project some external flux (sigh... I know, should have used it always). A 1 to 4 MIDI splitter. Soldering pen on the left I decided to try out a flux pen. It seemed to be less messy than rosin. I was unsure would it be as effective, though. Well, it was pretty good. It is easy to apply, and I could smear it on the PCB rather accurately. After administering the stuff, I learned that one must be relatively quick to do the actual soldering; it seems to vaporize quickly and lose some effectiveness.
Notes about what I do