Ed,
What kind of solder are you using?
I use about 680 for most stuff using wonder solder, and maybe crank it up to 700 for larger pieces -- that's with the standard soldering iron though, and most of the time I use an American Beauty resistance soldering station which doesn't have a temperature setting, only a current setting.
The 680 degree setting is just right for perfect flow of the solder through plated through holes with the wonder solder, even on small transistors.
-- Jim