With this DIY design, you can take your own temperature-controlled soldering iron out into the field
Good soldering requires good tools. In particular, a soldering iron that uses feedback to keep the tip at a set temperature works much better than one that doesn’t. That functionality is easy to find in a bench soldering station, but try to find a cordless iron with it, and you’ll be out of luck. This DIY solution solves that problem by marrying the business end of a Weller “Magnastat” soldering iron with a Maglite flashlight.
Detailed Instructions: How to Make a Temperature-Controlled Cordless Soldering Iron