"DeserTBoB" wrote in message
...

Electronics grade solder (60/40) uses rosin flux, which is water
soluable. The flux is there to deoxidize the joint while the solder
is in a plastic state. After some use, it will start to cake on the
tip and will start to burn into a black/brown crust, which isn't heat
conductive. Eventually, you'll have trouble heating the joint and
will wind up making "cold" joints.

MIL-spec soldering required distilled water, as the calcuim and
chlorimines in tap water can also contaminate a joint, but for
everyday electronic stuff, it's fine. Just swipe the tip through the
wet sponge every time and the moisture will clean off the rosin flux
form the tip. Then, "tin" the tip with just a little solder to give
you heat conductivity. Placce the tip on the mechanically sound joint
(presuming the joint has been cleaned already with a "solder sucker",
solder wick or an orange stick) and heat. When the JOINT is up to
melting temperature of the solder, then flow enough solder to cover
the joint...done.

Rules: NEVER use acid core flux. NEVER use 50/50 or 40/60 (radiator
solder). Good idea: Have a tin of rosin flux handy and a little tin
of "Re-Tip"...keep that tip nice and tinned and prevent tip corrosion.

What he said. I wipe the iron on the damp sponge before every soldering
operation, and afterwards dab a tiny bit of solder on the end so that it
goes back into the holder with at least a thin film of solder. At the end of
the session, I wipe it on the sponge one last time, then flow a good-sized
hunk of solder onto the tip and turn it off.

Peace,
Paul