I know when stick welding you drag the welding rod, I was told when mig welding that you're supposed to push the wire and not drag it,is this info correct? Also, how can I tell if I'm getting good penetration when using the mig? I usually wack the part I welded with a 3# ballpeen hammer a couple times.LOL. I do a pretty decent job at stick welding but this mig is new to me.
You might want to look at some of these: http://www.millerwelds.com/resources/video_library/ Very good stuff in there.
When you weld with the mig using solid wire and sheilding gas, you can push or you can pull. The key is to influence fusion by riding the wire on the leading edge of the puddle. You can use side to side or circlular motions to achieve this. If you ride the puddle (wire burning on the middle of the puddle) and just follow it along there is a good chance you will get cold lap and no fusion on one or both pieces of metal.
i like to set up hot so pulling on flats and same settings you can push vor vertical or upside down...again adjust your motions to keep good speed and penetration..
If you're a good stick welder you know what to do but this method being fresh to you has you "looking at too many things" for lack of a better description. Like all welding the puddle is the key. I like taking the gun and angling the top away from the joint and somewhat pushing the wire backward as I go and working the welded area in a "heart" shape, as in down to the bottom and once around, back to the bottom, etc. On smaller gauge material like sheetmetal or most things under about .125 I like to move the wire in and out of the joint if thick enough, or on thinner mat'l just watch the puddle and move steady. Mig gets hot really fast and a long consistant weld on sheetmetal (like body panels) is nearly impossible without a lot of screwin around. Best to spot it as you go, one spot weld over the other with no holes and allowing each spot before it to cool just enough for the red not to be seen through the speedglass. Like I said, if you're a good stick welder you know exactly what to do...watch the puddle and work it accordingly. You'll wonder how you ever did w/out it.
Flat Horizontal or overhead welding you want to push it If your welding in the vertical position you drag it downhill to get the best results.
ive noticed (i know i havnt been here that long) the hole pushing or pulling issue comes up quite a bit ..... im certafied (mig) to weld up to 3/8" plate and i was tought it doesnt matter unless your having issues with penatration ..... then you would slow down and run backhand just to keep the puddle molten for that extra second.....do whatevers comfortable for you ... ive noticed with mig people tend to run good beads and just not fuse the edges ... that was my problem aswell and was solved by just doing a 'c' motion and just pausing on on either side of the bead .... JMO
Just try to think of those Hostess Cupcakes withe white swirls on top when you're controlling that puddle! Not real technical but easy to visualize and explain.
Seeing how you already have welding experiance, this may not be helpful. There seems to be a trend with people just starting out with mig welding that they do not run enough 'heat', i.e. do not have the welder set high enough and end up laying all the wire ontop of the substrate.
^^^^^^^^^^^ What he said...you see that a lot. Also, as hot as a mig sometimes is (depending on mat'l thickness) they don't burn through mill scale real well. Now that comment may creat a shit storm but you might have to try it to believe it. For a long time I did a lot of mild steel mig sportsman drag stuff. I read about this in Nat'l Dragster and didn't believe it so I took a 6 X 6 common rollbar plate and gave it a shot. I welded 1/2 way around a bar to the plate (clean, no surfasce rust, un-sanded) and let it cool. I put the plate in a vice and whacked it with a 2# hammer. 3 blows and it snapped off like crazy glue. I ground one lightly with a 50 grit disc to remove the mill scale and repeated. After over a dozen severe blows it tore the plate at the weld, and I had to blast it pretty hard to do that. I was striking the bar on the side that was welded vs using the leverage of the un-welded side. Brain food for anyone reading this...
Pretty good piece of advice. I switched from stick to mig earlier this year and found out my self about goin side to side or circular to help fusion of both pieces, but as someone else said if you were good at mma, you'll know what to do, other thaN the "PUSH OR DRAG" thing, which is relative btw, all the rest comes pretty easily and by intuition. After all a good stick weld bead is a lot harder to pull than a clean mig one. Have fun!
with a MIG, when you first pull the trigger give it a second to burn in, don't start moving right away. If you do you'll have a big blob setting on top of your work. Also when to end the weld , let off the trigger and hold the gun still. The machine will allow gas to flow for a sec or two this will keep the weld from having porosity. On thicker stuff you can pull out of the puddle just a bit to "preheat" the area you are about to weld then back into the puddle. If you do this the same every time you get a great looking weld. I certified on stick vertical and overhead in 1973. The MiG is just something I enjoy doing. my welder is a Miller 250X
^^^ I was talkin about Apples dude^^^ i meant his link about push and pull techniques. He has 1 post, if thats his site it would be kool to have him here. As simple as that.
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