The Complete Handbook of Welding Guns & Plasma Cutters

Chapter 1: Understanding Welding Guns & Plasma Cutters

A welding gun or plasma cutter is a handheld or mounted tool that creates a controllable, sustained arc of electrical current jumping between two conductors through a gap, generating heat of several thousand degrees. That arc melts metal at the joint (in welding guns) or cuts through it (in plasma cutters). The tool itself does not do the joining or cutting—the arc does. Your job is to control where the arc goes, how long it stays, and what it melts or cuts.

This distinction matters because it separates the gun from the power source and the consumables. The gun is the handheld interface: it houses the trigger mechanism, delivers the wire or gas, directs the arc, and handles the extreme heat at the arc zone. The power source (welder or plasma cutter) sits across the shop and supplies the electrical current at the right voltage and amperage. The consumables—tips, nozzles, liners, and gas—are the parts that wear out or are used up. Professionals and service techs talk about these as separate systems because they are. You can change a gun on the same power source, upgrade the power source while keeping a compatible gun, or buy consumables for a gun you've owned for a decade.

Understanding how the arc forms and what keeps it stable is the foundation for everything else in this handbook. Inside the gun, when you pull the trigger, a small electrode (usually a continuously fed wire in