"Gas or No Gas?" is what I use to determine my MIG Torch Technique.
by Eric "Mangle" Franzen
(Berwick, Maine, US)
I don't know exactly why this stuck with me over the years but a teacher at a Tech. School I went to (for High School) told me that, if I was GMAW or MIG welding with solid wire and shielding flux gas (75%,25% or straight CO2 doesn't matter I use 2 bottles and mix my own at the machine and adjust my %'s to how hot or cold I want my molten filler metal for spray transfer ect. Spatter is another variable that I consider, and of course change gas types for stainless and other materials.) then you should do your best to "push" in the travel direction.
This would apply if you are FCAW with a shield gas as well (or duel shielding flux core) because ... argon as the majority of the shield gas, will provide a clean weld but does this with a "cooling" effect. In other words Argon = colder weld and CO2 = hotter weld, and with 75%, 25% pushing keeps the heat increasing in the direction of travel.
The "pull" technique is used when FCAW or just straight Flux Core Mig welding. Almost the same tricks as SMAW stick welding. This is because the build up of filler material is slower due to the majority of the wire's diameter is going to be slag when the weld is finished. Bottom line in my opinion is, this sounded like a good answer back then so I used it and still do 14 years latter. But results, quality and CONSISTENCY are what all welders should try to strive for. Techniques are the only "skill" that a welder can keep and call there own so I never try and argue against another welders technique.
In doing this, I have learned tons of new and proven ways of doing different things from some very wise and otherwise stubborn welders that I earned the respect from. After all there will always be an opportunity to learn something.... if you stay open minded. Thanks