Sugar Foot: If you have a soldering gun that has a removable tip/heating element you may find, as I have, that the contact points on the tip have corroded/oxidized to the extent that the electricity is not flowing through the tip as it should and thus the tip does not get as hot as it should. If you can, remove the tip and using some sandpaper or a wire brush clean the area where the heating element goes into the gun, reassemble and give it a try. Note also that not all fluxes are created equally; if you are still having problems, try a different brand of flux.