Weld test on tuesday, have some questions

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I have a weld test with a company on Tuesday. The test is 3g 3/8th's plate open bevel,1/8th inch gap, with a MIG down hill root, .045 flux core hot pass, and flux cap.  Now have never down any open MIG welding in school, only 6010. My question is what is your favorite setting to run it at for MIG open root? Yesterday i was playing around with it at school I was running it at 21.5 V and 400ipm, worked okay but I want more penetration. Any tips? Here is a pic of the backside of my best one. Attached Images
Reply:When I MIG I typically do it at about 120 wire speed & around 16V with the flow meter set around 20.How much practice do you have on MIG anyway?
Reply:Originally Posted by VydunasWhen I MIG I typically do it at about 120 wire speed & around 16V with the flow meter set around 20.How much practice do you have on MIG anyway?
Reply:Originally Posted by Killroy1942I have a 3G cert in MIG. I just never did any open roots with it.
Reply:It appears that you dont have full penetration on the joint. I'd focus on that myself.JasonLincoln Idealarc 250 stick/tigThermal Dynamics Cutmaster 52Miller Bobcat 250Torchmate CNC tableThermal Arc Hefty 2Ironworkers Local 720
Reply:The tech school has the guys do all their mig bevel buts with open root ( don't ask me why, I just help out... ). However all the vertical is done up not down for that. The only vert down that gets done is if one of the guys is looking to go work for one of the local companies who does production sheet metal. Then they practice a bit vert down on lap joints on thin sheet. That gets run hot and fast compared to the settings we usually use for thicker steel vertical up.One thing I have noticed is that some students have issues with suck back when they crank the voltage up too high trying to get more penetration. This is especially true when they run their 3/8" bevel buts in overhead. What I see there almost looks like what I see when they are having suck back issues with overhead..No government ever voluntarily reduces itself in size. Government programs, once launched, never disappear. Actually, a government bureau is the nearest thing to eternal life we'll ever see on this earth! Ronald Reagan
Reply:Originally Posted by DSWThe tech school has the guys do all their mig bevel buts with open root ( don't ask me why, I just help out... ). However all the vertical is done up not down for that. The only vert down that gets done is if one of the guys is looking to go work for one of the local companies who does production sheet metal. Then they practice a bit vert down on lap joints on thin sheet. That gets run hot and fast compared to the settings we usually use for thicker steel vertical up.One thing I have noticed is that some students have issues with suck back when they crank the voltage up too high trying to get more penetration. This is especially true when they run their 3/8" bevel buts in overhead. What I see there almost looks like what I see when they are having suck back issues with overhead.
Reply:I been doing a buttload of MIG welding on pipe the last few weeks. You see that line down the middle of your root? That means it's too hot.You need more gap and less heat. I would try a 5/32 gap with my heat set on 18.5 and 185. Seems like keeping the wire speed set to the same numbers as the volts has been working real good.You can use a land, or not. You just have to set your heat accordingly. I'm using a Miller machine, so I'm not really sure what the wire speed numbers mean, but those have been working real nice. If your wire gets too high, it wants to spit and pop, no good.On the flux core, I do the hot pass at 25/280. That's cold enough where I don't have to worry too much about blowing through.On the cap, I usually set the wire at 20 less than the volts for a position weld. So on your test, I would probably try it at 26.5 and 245 for a start and see how that does.Last edited by TimmyTIG; 04-21-2013 at 11:15 PM.
Reply:I just re-read your first post. They told you it has to be a 1/8th gap?If so, I would go with a knife edge, no land at all. Try the volts at 19 and 190. Keep the wire at the very leading edge of the puddle, pointing up into it.
Reply:16v and 160ipm on Miller PipeWorx 400 .035 with 75/25
Reply:Originally Posted by TimmyTIGI just re-read your first post. They told you it has to be a 1/8th gap?If so, I would go with a knife edge, no land at all. Try the volts at 19 and 190. Keep the wire at the very leading edge of the puddle, pointing up into it.
Reply:It's been a little while since I did open-root MIG, but I believe having your wire feed that high (400 IPM) will cause the weld pool to run down the joint too quickly. Your weld pool is probably building up and rolling downhill so quickly that you don't have time to manipulate and keep the electrode on either side of the bevel for sufficient fusion and reinforcement. What kind of manipulation and travel angle are you using?
Reply:you couldn't grind the land off?
Reply:Originally Posted by TimmyTIGyou couldn't grind the land off?