I would recommend using a soldering iron instead of a soldering gun. The soldering guns have large coils that can actually demagnetize your pickups. If you use one try plugging your guitar into an amplifier with the volume turned up to about 2 or 3 and listen to the hum generated by the soldering gun. If you hear this in your amplifier, then you know that the soldering gun can cause harm to your pickups. I would use a small pencil like soldering iron for all my guitar or bass soldering jobs.