It's always been my experience that 75/25 is a short circuit transfer shielding gas, as a minimum of 80% argon is needed to get out of short circuit transfer mode. We are using .035 wire and I'm not sure if we can crank the settings up high enough to get out of short circuit transfer with the 75/25 mixture. We use 75/25 for handrails and stairs, and I want to use it on structural steel, but short circuit transfer is not a prequalified mode of transfer in D1.1. Any thoughts as to how to make this work with our 75/25 existing gas?
75% argon will get you into spray transfer, but I always found I had to crank the voltage up and it was somewhat unstable. That is, the electrode extension was touchy.
I agree that the higher percentage of argon improves the operating characteristics. Try something like SG-AC-12% (12% CO2). That works. The old standby is SG-A0-2% (2% oxygen).
Al
I too agree that SG-AC-25 will produce spray transfer.
As already indicated, the increase in Argon will help. As the Argon percentage goes up, the transition current (changes from globular to spray) goes down.
You could use globular transfer mode. In my opinion, alternative gas is the best way to overcome the issue of stability if needed.
Im gonna try out some SC-AC-15 in my little shop that I use for welder qualification testing. That will cover all of my GMAW needs and also some FCAW wires.