Depending on what type of component you are removing the heat, time
and tools are all important. The general rulle its least amount or
heat in the least amount of time with no downward pressure and lots of
patience, thats what I preach to my students. As with all processes
the tools need to do the work and not be used improperly, which in
soldering means avoid at all cost pressure, soldering should not be
pressure activated. Pressure is what gets us in trouble when using
poor maintained equipment or improper techniques.
For most lead bearing solders, which is most likely what you are
dealing with, you should always start with a temp around 600 f and
modifiy from there. If its lead free you will need to up that
slightly, but not dramatically.
If you just do a lot of repair on the cheaper boards, I would suggest
looking into the circuit repairkits/techniques, some of the kits will
be better than the original when used correctly and again good well
maintianed tips and tools are key.
Anyway thats my 2cents email if you have questions or specifics of the
application you would like help with.
Ruffin Blackard
IPC Instructor
http://www.circuittechnology.com