I just finished a project involving using my trusty Handler 120 for modifying a trailer constructed of 3/16 inch angle (2 X 2 and 2 X 3). With some last minute advice from Ernie and a few other great folks on here, I got really satisfying results. Compared vertical up and vertical down, tried overhead (ended up turning the trailer over to cure that problem).
But success has bred curiousity. I've seen the recent threads and searched back through the Group on the emergence of newer and better dual shield wires and the debate over MIG for out of position work. And I've got the itch to just do some experiments and practice on stuff around 3/16 up to 1/4.
My first question involves multipass MIG for say 1/4 stock. I've tested my machine on 1/4 before, butt joint V-ed out, Hobart HB28 (E70S-6), and C25 flowing 25cfh. I tried to join pieces with 2-3 passes and found that as I watched the puddle and tried to judge penetration I would end up building the bead into a single pass weld. Whether I traveled fast and did multi passes or went slow watching the puddle/penetration and ended up with a single pass the results were as expected - I could break the weld with repeated impacts due to insufficient penetration. In fairness to that exercise I was using .030 wire and have since switched back to .024.
Is there some technique for running a multi pass with this size welder that I'm missing? Based on the experience with every project so far, I have gotten better penetration by traveling slowly to pump in heat and get penetration - too slowly to avoid building up the weld all in one pass. Should I set up the work pieces with a root gap? Leave a land of
1-2mm at the root of the bevel? I know the benefit of preheat from reading and using in some projects, but I want to try some things out for situations where the work can't be preheated easily.Second question involves out of position MIG. Just for trying to educate myself and build on my skills, would it be worth trying a roll of E71T and practice some out of position? From what I've read, that wire will still serve well for most of the general mild steel projects I come up with.
Third question: Even though the Handler 120 lacks the ooomphhh for .030-.035 wire when pushing the machine's upper limit, would it be a foolish exercise to try out some .030 dual shield working in the mid-range of the machine's ability? That's where much of my projects fall and again I figure the wire wouldn't go to waste. I've also never had a problem running .030 when working stuff less than about 1/8 inch.
TIA, Mark J