TIG Welding Roll Cage Help

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Ok, I finally finished TIG welding my tubing bender this week.  I will post some photos shortly in the project area.I mainly need some tips on method / technique for round tubing.  I am going to be welding 1-5/8 .130 wall tubing.  I wanted to get some opinions on how most people go about running the beads in out of position.e.g. a horizontal piece in between to frame tails.  Obviously this is going to be a vertical up weld.   Now would you try free hand or walk the cup?  How about walk the cup and have the filler already in the joint -vs- dipping while walking the cup?Anyone that has built a cage before please give me some pointers on various techniques that you have used.  A while back I had someone come over and TIG some welds on this and because I was not familiar with the TIG process I did not pay attention or ask the right questions at the time.  So I need some help now.  I have been running TIG welds on steel for a while now and my welding skills for a solid weld is pretty decent, so lets not focus on me taking my life into my own hands because this is a cage I understand this and I will also preform several destructive tests before I finish weld.  I mainly need to know some of the different techniques for what I am going to encounter with the angles etc.Thank you in advance!Build a Barstool Racer at BarFlyRacers.com!
Reply:i never have welded rollcages but id weld it free hand and dip just because thats how i weld but i would definately put some tubing in a vice and practice first 6G zirconium 702 GTAW 2" xxheavy6G P.E.D. carbon steel GTAW 2" xxheavy3G titanium Gr. 2 - Gr. 7 GTAW up to 3/4" 3G 316L stainless GTAW up to 1" 3G carbon steel GTAW up to 1" 3G Hastalloy GTAW up to 3/4"1G tantalum GTAW up to .060"
Reply:It can be done properly either way.  A lot of your decision may be made for you, based on the fitup of each joint.
Reply:Walking the cup around a coped joint requires some pretty large changes of torch angle to maintain a consistant arc length. Freehand for me everytime with this sort of work. Likewise, laying the filler in the joint is more trouble than it's worth in this case as the angles of approach are constantly changing in two planes for filler as well as the torchAs for tips, make sure that everything you need is close to hand- nothing more annoying than contorting yourself into position (often pretzel shaped) and then discovering your work lead isn't connected or gloves/mask/filler etc are out of reach  When coping the tubes lose the 'knife edge' at the longest parts of the fishmouth, take 'em back to full wall thickness. Once you've assumed the position, do a 'dry run' to make sure your mask/end of the filler don't hit other tubes as the weld progresses
Reply:im going to be doing a roll cage real soon...but i'll be using a MIG. sorry to cut in on your thread. but can i also get some tips...Lincoln Square Wave 175 TIGLincoln 110v flux core welder (my 1st)Clarke 180EN MIG
Reply:If you are going to be buidling a cage, you WILL Be welding out of position with either type of welder you choose.  If its moly then your stuck with having to use TIG - Rules state all Chromoly must be done with TIG process.  If mild you could use a combination, but it might not look right unless your real good with the MIG to camo or replicate the TIG look in a few hard to reach areas.  For insulation of nearby parts I have seen guys locally use balled up aluminum foil between the bar and area they did not want the heat to effect.  Seemed to work pretty well.  As soon as your done welding, get the aluminum out and then just put in a shield while it cools that touches neither.  A finger controlled tig torch might really help, but that will take some practice to get used to.  The one old timer here in town I was watching make a small stool that let him get in the car and work the peddle.  Seemed to work pretty well and he was about 6'3" tall.  Looked like he was setting on a chair you would see in a kindergarden classroom...seemed to work pretty well for him.  But there will be times when you have to lay on your back and work the peddle with your knee or equivalent.  When I had to lay under the car and tig using my knee, I just set it to where FULL peddle was the right setting, its not that bad once you get going.  Being able to fit everything you need into a specific place is tougher than anything I think you will find.  What looks like a lot of room, when you get in there with a torch and filler rods and two bulky hands fills up in a hurry and being able to see at the same time...Best Times with 434 Naturally Aspirated Vette60 - 1.261/8 -  6.37@ 107.25 MPH 1/4 - 10.08 & 134.9MPH1/4 - 9.60@144MPH
Reply:If you have some extra tubes fit up a couple joints outside the car and weld them out of position to practice. TIGing on those tubes overhead and vertical isnt hard you will get the hang of it it real quick, I always though the hard part was like hotrodder said, climbing in and getting to where you need to go.I never really walk the cup anywhere so I dont know about that, but I wouldn't lay the filler in the joint first, if something goofy happens with the puddle, your ribs are killing ya from layin in there funny or whatever else happens its nice to be able to just stop.Just my opinion.Also, lets say you have a tube all fit up and its tacked in, and when its welded it will be sealed at both ends. When you are welding up the second end, stop for a second and let it cool off, sometimes the air inside heats up and starts blowing out that last little bit of gap where your welding and blows your shielding gas away. I pause and let it cool for a sec then finish the last 1/4". Some guys drill holes to let the pressure out, im just lazy.Depending on how you cope the tubes there may be cutting oil in the tube as well, make sure to get that crap out, and I also like to sand the area to be welded til its super cleanLast edited by Burnit; 05-05-2008 at 06:14 PM.Reason: I cant spellYup
Reply:Lots of good information in these post!!!
Reply:I am going to cut and notch some scrap and practice.  I am pretty sure I can get the hang of this tubing stuff.  A few months back I ran some test welds on some 7/8" tubing and they turned out great for a first time run on small tube.  1-5/8" should also be easier due to the size of the tubing.Thanks for all the replies!Build a Barstool Racer at BarFlyRacers.com!
Reply:When going around "Fishmouths"..Concentrate the heat on the mating tube rather than the hi-spot on the Fishmouth..Too much heat there and the Fishmouth Gets very small all of a sudden and then its "Catch up time".....zap!I am not completely insane..Some parts are missing Professional Driver on a closed course....Do not attempt.Just because I'm a  dumbass don't mean that you can be too.So DON'T try any of this **** l do at home.
Reply:im going to be using 1 3/4 inch .130 wall thickness mild steel tubing. i'll be using a MIG to do this, as i said above.  how hard would it be to get the welds good enough to pass NHRA standards?should i spot weld all the way around to mimic the TIG process or just try and weld all the way around (as much as possible) without stopping my bead?NHRA standards state that pores can not be present in the weld. how do i make sure this dosnt happen?Lincoln Square Wave 175 TIGLincoln 110v flux core welder (my 1st)Clarke 180EN MIG
Reply:Originally Posted by sen2twoim going to be using 1 3/4 inch .130 wall thickness mild steel tubing. i'll be using a MIG to do this, as i said above.  how hard would it be to get the welds good enough to pass NHRA standards?should i spot weld all the way around to mimic the TIG process or just try and weld all the way around (as much as possible) without stopping my bead?NHRA standards state that pores can not be present in the weld. how do i make sure this dosnt happen?
Reply:thanks for the pics, nice work...but i'll only be using a roll bar, 2 bars to the rear, and a harness bar. its for a street car. so i should be able to reach all points. but in yours, im pretty sure i wouldnt be able to reach all areas with a MIG.Lincoln Square Wave 175 TIGLincoln 110v flux core welder (my 1st)Clarke 180EN MIG
Reply:Thanks for the photos!  Nice work!  Any tips on figuring the notching angles on some of that non 90* stuff?  I am trying to figure out how to determine where the halo need to be notched on the ends because it rests on the bent parts and not the straight.I have an idea on how to do this, but I would like to hear how some of the pros do it also.I have attached a photo to show you what I am talking about...Thanks! Attached ImagesBuild a Barstool Racer at BarFlyRacers.com!
Reply:The photos are not of my stuff; another guy I knows that I thought would come in handy for you guys asking.  The way I cope the tubes is to determine the "root or center" of the passthrough tube, then use a hole saw about the same diameter as the tube your going to be mating with.  In the case of your photo above because its going to be on an angle you will need a slightly larger opening,,,,but using the same diameter will get you pretty close as they walk around.  Then you have to hand fudge it with a lot of screwing around to get it just right before welding.  There is no easy way besides grinding/checking, grinding/checking.  Once you get one side done, then pray to god you don't screw up the other side or you get to start all over again.  By the time your about done, you will be pretty good at it.  And when you want to do more in about 1 year, you will have forgotten all the little tricks/techniques along the way you gained.  lol.If your just doing straight tube to tube pass throughs...all you have to do is determine the angle between the two.  Set it up with a good vice or mill like I have and use that same size mating tube hole saw and it does a beautiful job first time, everytime.  Toughest part there is finding the angle and setting it up right so your final lengths still fit between the two pieces.  I usually sneek up on the right length by taking a few skim passes once its pretty close.  The hole saws if good ones LENOX etc usually go through the tubing like butter.  Good luck and keep the swearing to a minimum.Best Times with 434 Naturally Aspirated Vette60 - 1.261/8 -  6.37@ 107.25 MPH 1/4 - 10.08 & 134.9MPH1/4 - 9.60@144MPH
Reply:Originally Posted by sen2twoim going to be using 1 3/4 inch .130 wall thickness mild steel tubing. i'll be using a MIG to do this, as i said above.  how hard would it be to get the welds good enough to pass NHRA standards?should i spot weld all the way around to mimic the TIG process or just try and weld all the way around (as much as possible) without stopping my bead?NHRA standards state that pores can not be present in the weld. how do i make sure this dosnt happen?