Resistance soldering is a soldering method that sometimes useful for hobby work. In this soldering methid an electrical current is flowed through one work piece, the joint and then the other work piece. Current through a resistances on the way generates heat. Most heat is normally generated on the joint because the resistance there is typically the highest.
Resistance soldering web page describes the technology in details. Resistancesoldering.com/ tells that resistance soldering can work also on some PCB work and similar applications. Resistance soldering is claimed to be good for soldering RF connectors, for example connectors on semi-rigid bases and central contacts on coaxial connectors. The soldering operation consists of clamping the parts to be assembled and adding a solder alloy. The heating process starts as soon as the foot pedal is activated and the temperature rises to the set temperature point. Look the video tutorial on soldering RF connector with resistance soldering.
According to Resistance Soldering Set document a resistance soldering set consists of a transformer that supplies 3 or 6 volts at a high current to stainless steel or carbon tips. The transformer is turned ON by a foot switch and OFF by an electronic timer (up to few seconds time). Since the soldering tips are hot only during the brief period of actual soldering, burning of wire insulation and melting of connector inserts are greatly reduced.
Build your own resistance solderer tells you how you can make your own resistance soldering iron with minimal investment. Resistance Soldering Unit is another page that gives instructions to build your own resistance soldering iron.