How To MIG Weld Gasless Flux-Cored Wires for Beginners
November 4, 2024
Flux-cored arc welding (FCAW), or gasless MIG, is an arc welding process in which a wire electrode is continuously fed through a welding gun into a weld pool. An arc is formed between the wire electrode and base metal, melting the base material while consumable filler wire is deposited, creating the weld.
Gasless MIG is almost identical to standard MIG except for the wire used. A hollow wire that contains flux, which produces a protective layer of slag on the finished weld, is used rather than a solid wire.
As the flux melts, it releases gases from within, which bubble to the surface. These internal gases protect the weld from outside contaminants until the puddle cools. This slag layer means a shielding gas isn’t needed for flux-cored welding.
When it comes to gasless MIG, one of the most common mistakes beginners make is the technique they use to create the weld.
Push vs Pull
There are two different ways to create a weld: pushing or pulling.
The push technique is where the wire is located at the leading edge of the weld pool and pushed towards the not yet welded part of the joint. This technique offers a better view of the weld joint and direction of the wire into the weld joint. It directs heat away from the weld puddle, allowing faster travel speeds and providing a flatter and wider weld profile for minimal clean-up.
The pull or drag technique is where the torch and wire are pulled away from the weld bead. The arc and heat are concentrated on the weld pool. The base metal receives more heat, deeper melting, more penetration, and the weld profile is higher with more build-up.
When it comes to gasless MIG welding, you need to use the pull technique. While pushing is preferred for standard MIG as it keeps the weld pull properly protected with shielding gas, that’s not the case for gasless. Pushing a gasless weld runs the risk of leaving slag inclusions or other defects in the weld.
Flux-cored wires, similar to stick electrodes, should be dragged. That way, you eliminate any chances of weld defects in your joint.
We’ve demonstrated the difference in results in our quick thirty-second video above so you can see it for yourself.