I need some good advice

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How yall doing i new to this site and need some professional advice Ive been welding for three months and my instructor told me if i welded down with mig it would be a cold weld is that true? One more thing how do you put a root with flux core because everytime i weld my root i never get enough penetration and when i turn my machine up i burn through please let me know or give me some pointers.
Reply:I've MIG welded pipe downhill and uphill.  Putting the root pass in downhill was no problem, but the fill and cover were extremely difficult.  Given a choice, I would not run the fill and cover downhill ever again.Every fluxcore weld I've ever done that was full penetration used some sort of backing strip.  I don't know how to weld with fluxcore on an open root and not burn through or leave slag deposits that compromise the root pass of the weld joint.Benson's Mobile Welding - Dayton, OH metro area - AWS Certified Welding Inspector
Reply:That tells me something about the quality of instruction you are receiving. A downhill root with MIG is easy and subsequent runs can be done downhill. That said, it is so much easier to run uphill with MIG after the root that there is hardly ever a need to run downhill. That is just MY experience with what I've used MIG for, pipe and structral. I'm sure others will have different experiences to share.I can't comment on downhill root with fluxcore because I've never had a need to try it. All my fluxcore except for some really thin galvanized pipe has been hobby welding where strength wasn't a big deal. As a note, I used Uniweld Alloy E71T-GS .035 Fluxcore wire for the galvanized pipe on the advise of my LWS who said it was designed for welding galvanized material and it welded better than any thing else I've ever used.
Reply:Any down hill weld mig, stick or whatever requires a great deal of attention. It is quite easy to let gravity take over and end up with the puddle over running the weld resulting in little or no fussion. Down hill welding can be your best friend or it can really bite you.
Reply:vertical down is a waste of time in MOST SITUATIONS, not all, but most.  Learn how to run vertical up, you will get better penetration.  Welding downhill will cause the puddle to fall down in front of you arc if your not doing everything perfectly.Fluxcore is much different, and every wire runs different.  they each have there own little quirks.  give some background, what wire your using, what are your volts and amps at, what size plate are you working with, angle of the bevel, joint type, positionall those things will make a difference in how you run a root pass
Reply:Oldtimer, Hopefully it tells you that I didn't waste my time at Hobart(HIWT).  Their class on MIG welding pipe is short, only one week.  I think it should have been 2 weeks.  They focus on teaching uphill methods, but on the last day the instructor had us try downhill for fill and cover.  I think I could figure it out, given more time.  But compared to running the fill and cover uphill, I just can't see the need to try.drivethruboy, 6010 stick downhill on pipe is almost as fast as MIG welding, I think.  So in my mind that's one of the places where downhill welding serves a purpose.  It's not as sensitive to technique as downhill MIG welding either, although it definitely requires skill to do it and meet API1104 standards. Originally Posted by OldtimerThat tells me something about the quality of instruction you are receiving. A downhill root with MIG is easy and subsequent runs can be done downhill. That said, it is so much easier to run uphill with MIG after the root that there is hardly ever a need to run downhill. That is just MY experience with what I've used MIG for, pipe and structral. I'm sure others will have different experiences to share.I can't comment on downhill root with fluxcore because I've never had a need to try it. All my fluxcore except for some really thin galvanized pipe has been hobby welding where strength wasn't a big deal. As a note, I used Uniweld Alloy E71T-GS .035 Fluxcore wire for the galvanized pipe on the advise of my LWS who said it was designed for welding galvanized material and it welded better than any thing else I've ever used.
Reply:Downhill 6010 on pipe is common practice in the oilfield and has been since 6010 was introduced. I've used gmaw downhill a bunch and never had any failures. I get better results with flux core uphill, but do on occasion use it downhill (forget about it if you can't get it absolutely clean as in bright and shiny). I have used flux core on an open root both uphill and downhill depending on what I was working on (small inclusions weren't a concern) but never on pipe. Never had any reason to try it. I have read that pulsed mig is the thing for open root on pipe, but I don't have a pulser to try it with.The difference between art and craft is the quality of the workmanship. I am an artist.
Reply:like i said, running downhill is acceptable in some situations.  Welding cofferdams that are leaking for marine pile driving the only way to run a pass is going downhill with 6010. going uphill just wont work
Reply:big thanks to everyone for the info.