Welding Round Tubing - Technique Advice

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I'm really struggling with welding round (DOM) tubing.  I can get the proper penetration, and the proper weld aesthetic - WHEN I can actually follow the valley.  But it's so very hard to do, on account of the geometry!Can anybody give me some really practical advice or clever tips on technique?  I've been told that this is one of the hardest types of welds to master.  Now, I realize that there is no "fast path" to becoming good at welding - but I'm sure most of you have struggled through something, only to realize later that it would have been easier if you had known some silly little thing, which you now know.For reference - I start off by notching the tubing, deburring, wire wheel prepping the weld area, checking fitment, and tack welding at the 12, 3, 6, and 9 positions.  12 and 6 are a little stronger tacks than the others. (I'd say they are "globby")  I use a downhill pull technique.  I've not had any luck at all with uphill, so I started with the technique that I'm closest to success with.  About 30% of the time, I can produce something that resembles a decent weld.Maybe I'm holding the gun wrong?  It certainly is awkward. Maybe I'm not propping correctly? It seems like everytime I get focused on one aspect of the process, I lose track of another. Angle changes, nozzle distance, etc, etc, etc...I'm not going to stop practicing this until I can do it effortlessly! 1979 VW Rabbit - Mid-Engine, RWD, SwapFacebook - MK1 SwapMillermatic 211
Reply:I don't know anything about mig, but with tig it's all about being able to roll the torch to keep a proper torch angle. That is what gives the consistent  bead appearance. I'd imagine mig gun angle is the same. Take a lot of practice runs before you pull the trigger. Practice controlling the gun angle as you move around the joint.Mike ZanconatoZanconato Custom Cycles @mzank on Instagram
Reply:Sorry, I should have stated more clearly that is definitely MIG, and I have practiced hours of movement with the gun, and no weld.   With MIG welding, is it easier/better to do this type of weld with one hand, or fully propped?I'm finding it hard to stay on the path, due to all of the changes in geometry.  Sometimes, I just flat out lose sight of what I'm welding, and I'm not even really sure what's blocking my vision. Sounds stupid, but that's my struggle...1979 VW Rabbit - Mid-Engine, RWD, SwapFacebook - MK1 SwapMillermatic 211
Reply:If you just need more practice, weld circles around a piece of pipe until it's second nature.This is similar to stacking beads on a flat plate - half overlap each previous weld.Saves material and gives you a lot of practice with minimum prep.Keep dunking it in water after each pass or two so it doesn't heat up too much to keep practicing.Dave J.Beware of false knowledge; it is more dangerous than ignorance. ~George Bernard Shaw~ Syncro 350Invertec v250-sThermal Arc 161 and 300MM210DialarcTried being normal once, didn't take....I think it was a Tuesday.
Reply:Yeah, that's a really good bit of advice.   Might not hurt to chuck a few pieces in the lathe, and put a series of v-grooves or notches, to give a visual trace path...  I like that idea.1979 VW Rabbit - Mid-Engine, RWD, SwapFacebook - MK1 SwapMillermatic 211
Reply:Originally Posted by solid7I'm really struggling with welding round (DOM) tubing.  I can get the proper penetration, and the proper weld aesthetic - WHEN I can actually follow the valley.  But it's so very hard to do, on account of the geometry!Can anybody give me some really practical advice or clever tips on technique?  I've been told that this is one of the hardest types of welds to master.  Now, I realize that there is no "fast path" to becoming good at welding - but I'm sure most of you have struggled through something, only to realize later that it would have been easier if you had known some silly little thing, which you now know.For reference - I start off by notching the tubing, deburring, wire wheel prepping the weld area, checking fitment, and tack welding at the 12, 3, 6, and 9 positions.  12 and 6 are a little stronger tacks than the others. (I'd say they are "globby")  I use a downhill pull technique.  I've not had any luck at all with uphill, so I started with the technique that I'm closest to success with.  About 30% of the time, I can produce something that resembles a decent weld.Maybe I'm holding the gun wrong?  It certainly is awkward. Maybe I'm not propping correctly? It seems like everytime I get focused on one aspect of the process, I lose track of another. Angle changes, nozzle distance, etc, etc, etc...I'm not going to stop practicing this until I can do it effortlessly!
Reply:I first learned to weld on TIG, so I can appreciate that, Tom.  Unfortunately, what I have, is what I've got, for now...  Gotta make do with it.1979 VW Rabbit - Mid-Engine, RWD, SwapFacebook - MK1 SwapMillermatic 211
Reply:if all i got is a 8lb sledge hammer it will always be hard to pound little brad nails with it
Reply:Come on now...  You know as well as I do that there are many people who weld DOM tubing with MIG that meet or exceed both functional and aesthetic standards.  We're not comparing sledgehammers to scalpels, here.  And a TIG is still out of the question right now, so...1979 VW Rabbit - Mid-Engine, RWD, SwapFacebook - MK1 SwapMillermatic 211
Reply:I saw something about twisting the torch for TIG so that it is preloaded to turn the direction you need it to as you move around the tubing.  It seems like it would work with a MIG gun as well.  I've been trying it with TIG and 4130 tubing and it works pretty well.Hope that makes sense.Outrunning my headlights since '81.
Reply:That does make sense...  But I don't really have a feel for that twist.  I've been sorta looking for a tip like that.  What works best, in your experience?1979 VW Rabbit - Mid-Engine, RWD, SwapFacebook - MK1 SwapMillermatic 211
Reply:It helps to get set up and propped to make your weld and then make a couple dry runs with the gun. That way you'll know the motions you need to keep a good gun angle before you pull the trigger. This will also let you know if you've propped too rigidly and won't be able to complete the weld.
Reply:It just takes practice. You don't say what your welder is, but if it has a large gun change it out for the lightest most flexible one you can get. When I was doing racks for ATV's the most popular welder with the guys was an sp170 lincoln because the gun was most flexible.Yeah, I know, but it'll be ok!Lincoln Square wave 255Miller Vintage mig30a spoolgunThermal Dynamics Pacmaster 100xl plasmaSmith mc torchEllis 1600 band saw
Reply:My welder is in my sig - it's a Millermatic 211.I have seen the guns with the flexible tips in various videos.  I've kinda wondered if those were help or hype.  Never seen one in real life.1979 VW Rabbit - Mid-Engine, RWD, SwapFacebook - MK1 SwapMillermatic 211
Reply:Got any pics of the joints your welding?How big of tubing, and what wall thickness.IMO mig is way easier to use then tig for small pipe joints.Just a couple welders, big hammers, grinders, and torches.Work will free you.Men in dirty jeans built this country, while men in clean suits have destroyed it. Trump/Carson 2016-2024
Reply:First off, what position is the pipe ?...judging by the way you tacked it, it is in the horizontal fixed position. So, you have to weld the joint uphill. Basically, 6 to 12, and 6 to 12. (not all in one shot, though...in segments).You'll probably have to hold the gun sideways, to be able to rest your hand on the pipe.You have to place your head "above" where you are welding. In other words, if you start welding from the 6:00 to 7:30 segment, get your head above the 7:30 position, and watch the weld coming up at you. This way, you'll be able to see the bevel.It's tough to watch the puddle doing this, so you have to rely on inherent skills, and know that the weld is burning in there properly.If the gun is ever at "eye level" you won't be able to see where you're going...the gun will be in you line of sight.Pipe welding is very challenging.RichEDIT...after reading the next few posts, I see that you are welding a small-diameter tube roll cage.For some reason, I thought you were welding (or practicing) on something bigger. Never mind the above advice....Last edited by steelsurgeon; 02-08-2016 at 02:30 PM.Reason: Wrong advice for the actual situation...
Reply:No, no pics right now, as I'm away from home with work.  However, it's pretty typical roll cage stuff. (under 2200 lbs vehicle)  1-1/2" X .095 wall DOM.  I'm notching a close fit, to ensure consistency of welds. (limited by skill, at the moment)1979 VW Rabbit - Mid-Engine, RWD, SwapFacebook - MK1 SwapMillermatic 211
Reply:Downhill mig is the only way to go here, just set your machine for 1/8" thickness with the auto set.Just aim at the center of the joint and move.Just a couple welders, big hammers, grinders, and torches.Work will free you.Men in dirty jeans built this country, while men in clean suits have destroyed it. Trump/Carson 2016-2024
Reply:Yes, sir.  That's exactly what I'm doing, at the moment.1979 VW Rabbit - Mid-Engine, RWD, SwapFacebook - MK1 SwapMillermatic 211
Reply:The only thing for it is practice. Practice, practice, practice. I saw an old muffler guy weld a new catalytic converter to my old ranger with no hood on, just closed his eyes and did it, came out perfect.Also, be careful with the downhill MIG, it's really easy to get a cold lap.Ian TannerKawasaki KX450 and many other fine tools
Reply:Please elaborate a bit more on the cold lap.  I know what it is, but what is the main reason for it, and what is the best way to avoid it when running downhill?I always assume that when I start to see globs wanting to run, my weld is in trouble. (makes it hard to trace the puddle) Not sure if the 2 correlate, or if your cold lap is from low voltage.1979 VW Rabbit - Mid-Engine, RWD, SwapFacebook - MK1 SwapMillermatic 211
Reply:Originally Posted by solid7Please elaborate a bit more on the cold lap.  I know what it is, but what is the main reason for it, and what is the best way to avoid it when running downhill?I always assume that when I start to see globs wanting to run, my weld is in trouble. (makes it hard to trace the puddle) Not sure if the 2 correlate, or if your cold lap is from low voltage.
Reply:Thanks for the explanation, Ian.I've tested a lot of the pieces that I've practiced, and I seem to be getting very good penetration.  It took me awhile, but I think I have gotten the hang of downhill, at least for the fusion.  I guess as others have said, it's just going to be more practice, practice, practice, to ensure that I can follow the path around the changes in curvature.My flat pieces, doing a fillet weld, or lap joint downhill on a straight vertical, seem to come out really nice.  When I can, I'll post some pics.1979 VW Rabbit - Mid-Engine, RWD, SwapFacebook - MK1 SwapMillermatic 211
Reply:Don't know if this will help, but I thought it had some good tips.http://www.profabricationtechniques....elding-tubing/
Reply:Originally Posted by MoparfeverDon't know if this will help, but I thought it had some good tips.http://www.profabricationtechniques....elding-tubing/I don't think a "Flexible" gun would help? All the pipe/tube that I have done requires a practice move around the weld area to figure out Head/Neck position to hold line of sight on the Joint and wire coming out of the Gun.IMO of course, but this is what works for me!