Trouble with arc with MIG

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Got the bottle today, hooked it all up.  Set the CFH to begin with at 10 and put the .025 wire in the machine, switched up the polarity (opposite of flux core) and started.I can only get the arc to 'pop' stop 'pop' stop.  I havent been able to get a steady arc going, not even enough for a tack.I changed through nearly every voltage setting, and wire speed and a few different cfh settings.  But still can't get it to maintain an arc for  atack, or bead.  What I saw was that the wire would arc when it hit the metal, but it appeared it arced all the way back to the nozzle, then it would wait to arc again until the wire contacted the metal (obviously).  I adjusted wire speed first and it didnt solve anything, so I tried to switch voltage settings as well, but no luck.  What in the world am I doing wrong?  And the color I noticed was a greenish color while it would arc.  DOnt know if that helps much either.Machine is a Pro Mig 175, mix is 75/25 ar/co2.  And I'm incredibly excited to learn a new process, but man I just can't get the settings right.  All the times I have MIG'd before, the machine was set up by another person.Lincoln Pro-Mig 175Harbor Freight cart and accessoriesAnd learning...
Reply:Don't know your machine but what you're describing is WAY to high voltage. Turn your voltage down and your wire speed up. It should "push" the gun away from your workpiece, then start working the wirespeed down. Isn't there a guideline chart inside the cover ?Anything worth doing is worth doing RIGHT
Reply:Did you change the contact tip to a .025"?Did you change the drive rolls to the .025" size?Did you reset the tension on the drive rolls for the thinner wire?It sounds like the wire can't feed because the drive rolls are just spinning on the thinner wire.- Paulhttp://all-a-cart.comWelding Cart Kits and accessories
Reply:Good catch Paul, I wouldn't have given that a thought. Just automatically do that when I go from one to the other.Anything worth doing is worth doing RIGHT
Reply:Originally Posted by ZTFabDid you change the contact tip to a .025"?Did you change the drive rolls to the .025" size?Did you reset the tension on the drive rolls for the thinner wire?It sounds like the wire can't feed because the drive rolls are just spinning on the thinner wire.- Paul
Reply:Clean metal...no millcoat ?Anything worth doing is worth doing RIGHT
Reply:ALright, I got it.  I got a nice bead going.  I odnt konw if you guys have seen this, but the wire on the first part of wheel had little nicks in it and when I looked at it closer it the nicks were making the wire come out straight for about an inch, then holding it for a millisecond then coming out angled.  I let it go for a few seconds and it looked like it was making an octagonal circle.  I took the spool of wire out and replaced it and reset everything back to the way it was.I've never seen a spool of wire come like that.  It's only a 4" 1lb roll though, so I dont know.  The second one came out ultra smooth and the arc stayed steady.THanks guys!!!Lincoln Pro-Mig 175Harbor Freight cart and accessoriesAnd learning...
Reply:I know this is far from perfect, I didnt even hit it with a wire brush, but does that look alright for running 10cfh?  Figured a quick pic could help you guys help me determine if I should run it higher.  And I know that penetration probably isnt good, I just needed to run some beads.  They looked like this.Last edited by bignick31985; 08-15-2007 at 07:36 PM.Lincoln Pro-Mig 175Harbor Freight cart and accessoriesAnd learning...
Reply:Glad you got it figured out.I would say that a little more heat would be good...other than that it looks like you've got a good start.10cfh is fine. The weld you have there is perfectly shielded so no need to waste gas but as you weld more you may want to bump it up to about 15cfh as you will find that when turning corners the gas may dissipate some.- Paulhttp://all-a-cart.comWelding Cart Kits and accessories