On Tuesday, February 9, 2016 at 1:29:13 PM UTC-5, Jeff Liebermann wrote:

6. Hit the connection with some solder before unsoldering to make the
old solder flow. Slopping flux on the pad doesn't help because the
flux will vaporize before the solder melts.


Adding fresh solder adds flux assuming you are using a flux core solder. While the carrier will vaporize, the flux solids remain. I always deflux when the repair is completed.


I'm undecided if hot air desoldering is any better than a soldering
sucker for through hole parts.

Not sure either, but I often use hot air to preheat the area before using the iron. Nothing ruins desoldering faster than heat sinking.