I also have the mPulse 30 and I had hoped to use it to weld sterling silver ear posts and jump rings/bails to my lost wax cast designs. I do have argon set up but unfortunately even when using the argon gas I had results similar to yours - weak welds and posts that snapped off easily.
I’ve tried several solutions including using the sterling posts with small pads on the bottom to provide more surface area and material to weld, blunting my electrode tip, adding laser wire at the welded connection point, and varying the power used for the weld (which as you know is the only setting able to be adjusted on the mPulse).
None of these resulted in satisfactory welds on my ear posts, so I went back to soldering on my posts and only use the mPulse 30 for closing jumpring and attaching chain components.
Overall I still find it useful to my workflow as I make a lot of pendants and my torch set up isn’t very sophisticated so soldering delicate chain work was difficult. I am disappointed though because I feel the Orion promotional materials made it sound like welding silver ear posts was very doable, and from everything I’ve read here and on Facebook groups I belong to no one has figured out how to do it reliably with the limitations of the mPulse.
Sorry for the bad news :/