push or drag

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Hello every one, I am new here, Have been a professional welder/fitter 3 years.We mostly use metal core wire ( Lincoln MC-6) at work. On of the guys I work with insists that metal core wire in spray transfer must be pushed (forehand technique). Is there any wisdom to this or does he need to check his facts ??brad
Reply:Try a search on this site, this has been discussed.Educate me on this, does metal core produce much slag?  Some but much less than stick or shielded flux core?  Does metal core truely spray, similar to solid wire?In general the rule is "if there is slag, then drag", and this probably makes sense for many applications of stick or flux core to prevent entrapping slag ahead of the puddle, but I'm not an expert in this regard, and  rules are made to be broken.  And this must depend on the joint and position, since for instance I don't think you typically drag a vertical up weld.I do know that with pulsed spray solid wire MIG, a push angle produces a flatter, smoother profile, probably with somewhat less penetration, than a drag angle, maybe this is what your co-worker is going for.Last edited by pulser; 10-13-2010 at 11:07 PM.
Reply:My instinct would say push.   The gas coverage is better, and I'd think the penetration could be controlled a lil better w/ some practice.       I don't think I ever ran that particular wire though.
Reply:Hi Brad, and welcome!Anything you do with hard wire can be done with MC using lower input energy. Spray happens at lower volts allowing H4 condition welds with good operator appeal. MC and flux cored wires also allow out of position welding at lower wire speeds where larger solid wires are harder to get set well.Matt
Reply:Thanks all for the replies.Pulser:The slag produced by metal core wire is similar to hard wire, leaving small siliceous slag islands so it is definitely less that SMAW or FCAW. Metal core sprays with a wide softish plasma cone (apparently since the powdered metal core does not conduct well the majority of the current travels on the outside of the tube which accounts for this). We us 85/15 and have alternative procedures for 90/10.my co-worker says that with spray transfer you MUST push. He has offered little if any reason; I believe that he was trained this way and simply will not be told otherwise.I find that I weld equally as well whether I drag or push and tend to tailor my technique to the conditions at hand.Matt:I do not believe that MC or at least the MC that I am familiar with can be used out of position. I weld 90% of my work 1g, 1f , 2f.thanks Brad
Reply:Originally Posted by Brad NThanks all for the replies.(snip)my co-worker says that with spray transfer you MUST push. He has offered little if any reason; I believe that he was trained this way and simply will not be told otherwise.I find that I weld equally as well whether I drag or push and tend to tailor my technique to the conditions at hand.Matt:I do not believe that MC or at least the MC that I am familiar with can be used out of position. I weld 90% of my work 1g, 1f , 2f.thanks Brad
Reply:I'm certainly no expert on the subject, but when I first started at a place which used metal cored wire (1.2mm Praxair FG 700) I was in the same situation as you, nobody could tell me what was best, so I just played around a bit with the angle and found that it seemed to work best perpendicular or with the slightest of push angle. When I say best, I mean it gave me the smoothest, most visualy pleasing bead. I never macro etched them (was a bit of a sweat shop and I certainly wern't going to do weld penetration tests in my lunch break), but passed the NDT when required, never had any more problems than you would expect with MAG and nothing I welded ever came back. We were using tri-mix gas and I found it lovely wire to run on the EWM 500amp sets that they had, from doing stringers on thin material all the way up to multipasses on the thick stuff. The only complaint I would have is that it was a bit smokey, but then again the only ventilation we had was a couple of fans in the ceiling (which the boss would keep switching off to save money) and the doors open.