The problem caused by using a low-power soldering iron, or a tip that's too small, is that the iron [u]must[/u] be able to deliver heat to the connection faster than the wires and terminals can drain the heat away. Otherwise, instead of just heating the connection, you're also heating the wire, the entire terminal, the internals of the pot, and any components you're connecting to.

For working with guitar controls, you need a temperature-controlled iron with a clean tip that has a working surface about the same size as the connection you're making. Without temperature control, something on the order of 20 or 30 Watts is good.

• Melt a dab of electronic-grade, flux-core solder onto the tip. This will fill any small air gaps between the tip and the connection, making much quicker heat transfer.
  



• Feed the solder into the connection, [u]not[/u] onto the tip of the iron.
  



• As soon as the connection is thoroughly 'wetted' with solder, remove the solder and then the iron. In that order. You don't need to flood the joint to get a good connection. And after you suffer the embarassment of having your solder stick to the connection as you pull the iron out of the way, you'll understand why you back away with the solder first. :o
  



• Do not blow on the hot connection to cool it down! This can crystalize the solder, making a 'cold joint' which can actually pick up radio signals sometimes. If you're worried about overheating components, use some heat-sink clips to protect them.

Once you get the hang of getting the heat into the connection quickly, feeding in some solder, and getting out quickly, you'll find you can consistently make neat, shiny, reliable solder joints.