I use a 25w Iron too, and to be perfectly honest it's a tiny bit weak for PCB work. I would imagine 40w or higher would be much better as you really don't want to keep the iron on the PCB for too long as you risk permanent damage.
The trick though is to make sure the iron is up to full temperature and has been tinned prior to putting it anywhere near the board. If the solder is forming balls, then you probably didn't have the hot iron touching both parts, ie: the capacitor leg and the solder point on the PCB. Both need to be heated by the iron in order for the solder to flow and attach properly.
The trick though is to make sure the iron is up to full temperature and has been tinned prior to putting it anywhere near the board. If the solder is forming balls, then you probably didn't have the hot iron touching both parts, ie: the capacitor leg and the solder point on the PCB. Both need to be heated by the iron in order for the solder to flow and attach properly.