Mig question please.

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I have never been actually tau ght or went to a welding school,just seen or watched alot of different welders and different techniques and started welding..I did search but didnt find exactly what I needed so if there is a thread here  missed please let me know.I have seen in books and welding tips different ways to go with the direction of your welding while using a mig. I first learned to O/A weld when it was mainly used for exhaust systems until I learned to do exhaust better and faster with migs. As some of you know welding usually above your head is not as easy as on a bench or directly in frt of you. this made me learn to weld down alot of times or what most would call pulling instead of pushing.I got into the habit of pulling my on most all my welds and really havent had any breakage issues or anything and have welded some parts that needed to be stout but as we all know that doesnt always matter as anything can or will break if not done right and the perfect conditon exists.Is it preferred to push or pull I guess is the main question or is a matter of preference?? I can see where pushing would keep your shielding gas directly above the newly laid beed where as a pulling motion would tend to possibly not expose the weld bead to the full amount of the gas.I will try to take a few quick pics of some of my welds with my mig and post here so maybe I can be a little more educated by some of you professionals.Thanks for your time,and hope to learn some basics that I may have missed along the way.
Reply:slammed1,  You're correct regarding the shielding gas on horizontal 'push' which typically produces a nicer looking bead.  Horizontal 'drag' provides deeper penetration as does vertical 'up' as apposed to vertical 'down' where you're trying to stay ahead of the puddle.  Shielding gas (C25-vs.-CO2) plays a role in both appearance (less spatter) and penetration (heat) too.MM200 w/Spoolmatic 1Syncrowave 180SDBobcat 225G Plus - LP/NGMUTT Suitcase WirefeederWC-1S/Spoolmatic 1HF-251D-1PakMaster 100XL '68 Red Face Code #6633 projectStar Jet 21-110Save Second Base!
Reply:Well, it really depends on what you are trying to do.  Pulling the gun will yield a bit more penetration than pushing.  and you are right pushing will alot of time give better gas coverage.  As far as welding down hill goes I will usually weld down hill on thinner materials.  Anything less than 1/8"  material and I weld uphill on as it yields a good bit more penetration.I'm a Lover, Fighter, Wild horse Rider, and a pretty good welding man......
Reply:thanks for the replies guys.I will post up a few pics and let you see what I may need to work on.
Reply:Originally Posted by Hammack_WeldingWell, it really depends on what you are trying to do.  Pulling the gun will yield a bit more penetration than pushing.  and you are right pushing will alot of time give better gas coverage.  As far as welding down hill goes I will usually weld down hill on thinner materials.  Anything less than 1/8"  material and I weld uphill on as it yields a good bit more penetration.
Reply:There's a trailer fabrication place over in the town east of here.  They were having QC problems.  Trailers were literally breaking.  They hired a "specialist" to come in and look at what was goin' on.The guy found that the welds were all downhill on pretty thick plate.  The upshot of the whole deal was that the welds were changed to uphill, and the bulk of the problems went away.From what I understand about the way it was explained to me was.........  When going downhill, unless you're careful, you're depositing into slag, making a porous weld.  Going uphill the chances are greater that the wire is actually penetrating the parent metal.  The slag is behind you."Any day above ground is a good day"http://www.farmersamm.com/
Reply:Forehand preheats the metal before the weld is deposited.  Backhand doesn't so all the heat goes into penetration.  Back hand beads are taller and narrower in the part you can see and the part you can't.  So push for good looks on thin plate.  Pull for penetration on the thicker stuff.  You can always pull the first passes and push for the final cap.  Down hill is fine for small stuff. You can get full penetration if enough heat is used.  I mig exhaust down hill all the time.  Most everything else is uphill, but I don't work with thin stuff.Each individual situation should be evaluated first.David Real world weldin.  When I grow up I want to be a tig weldor.
Reply:Originally Posted by RojodiabloI think you meant anything MORE than 1/8" you weld uphill for more penetration.
Reply:Originally Posted by farmersammThere's a trailer fabrication place over in the town east of here.  They were having QC problems.  Trailers were literally breaking.  They hired a "specialist" to come in and look at what was goin' on.The guy found that the welds were all downhill on pretty thick plate.  The upshot of the whole deal was that the welds were changed to uphill, and the bulk of the problems went away.From what I understand about the way it was explained to me was.........  When going downhill, unless you're careful, you're depositing into slag, making a porous weld.  Going uphill the chances are greater that the wire is actually penetrating the parent metal.  The slag is behind you.
Reply:Originally Posted by David RForehand preheats the metal before the weld is deposited.  Backhand doesn't so all the heat goes into penetration.  Back hand beads are taller and narrower in the part you can see and the part you can't.  So push for good looks on thin plate.  Pull for penetration on the thicker stuff.  You can always pull the first passes and push for the final cap.  Down hill is fine for small stuff. You can get full penetration if enough heat is used.  I mig exhaust down hill all the time.  Most everything else is uphill, but I don't work with thin stuff.Each individual situation should be evaluated first.David
Reply:Originally Posted by MigionThere are a lot of different terms in this thread and I am a little confused  We have push/pull, uphill/downhill, forehand/backhand, vertical, horizontal, lead/lag.  Are the references push/pull, uphill/downhill, forehand/backhand, lead/lag all being used here to mean the same thing?
Reply:Push, Forehand.  The mig gun faces a little towards the finish line.Welding direction ---->   mig gun or torch ______\Pull, drag, backhand.  The mig gun faces the start line a little.   Welding direction ---->   Mig gun or torch  ______/    Always forehand for vertical up. (the gun points up a little)I can't say for down.  I dunno.  I keep the gun pointed up a little.DavidReal world weldin.  When I grow up I want to be a tig weldor.
Reply:Originally Posted by David RPush, Forehand.  The mig gun faces a little towards the finish line.Welding direction ---->   mig gun or torch ______Pull, drag, backhand.  The mig gun faces the start line a little.   Welding direction ---->   Mig gun or torch  ______/    Always forehand for vertical up. (the gun points up a little)I can't say for down.  I dunno.  I keep the gun pointed up a little.David