Square tube - welding @ right angle "end to side"

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Material  - 2" square tubing, appx 3/32 wall, mild steelProcess - TIG, 3/32 electrode; 1/16 rodAmps - 100-125ish?Gas - argon (incidentally, I'm just reading some other posts to the effect that pure argon is not the right stuff for mild steel... this is what we've always used where I work and learned to weld - so I never knew any different...)The issue: I've got 2" long pieces of 2" square tube that I'm welding in a "stack," alternating directions 90degrees.  Per this orientation the sharp corner of the tube end lays next to the curved corner of the tube's side; I'm having trouble getting a nice, consistent weld that I don't need to grind - problematic because it's nearly impossible to grind this without ruining the edges. Sometimes I've been able to get the weld to "flow" in this gap by pressing the filler rod in and moving the torch without any "touch weld puddle/remove/move/repeat" such that it looks almost polished when I get done - no "coin stacks" just a smooth rounded surface... but in other cases I'm ending up burning into the sharp edge (tube end) or the rounded surface, or both.  OR not actually joining the 2 pieces at all (gaps in the weld). I'd be happy with a nice, small weld that was consistent, even if it has to be puddled a bit...What I'm wondering is: Is there an "accepted" way to make this weld?  Orientation? (I've been welding with the "stack" lying on it's side, so that the weld is facing up as I make it.)Tricks w/ torch angle? (I've been pointing straight down into the gap, sometimes shading toward the "tube side" side of the weld and away from the "tube end" side...)Amperage rules of thumb?Would it help to "pulse" the weld - would have to do it manually as the welder doesn't have this functionality...Filler rod sizes? (tried 3/32 as well, 1/16 looked better generally...)Any suggestions, or other info i can provide? (would have posted a photo, but my trials are at work... ack!)
Reply:Originally Posted by peanutjarGas - argon (incidentally, I'm just reading some other posts to the effect that pure argon is not the right stuff for mild steel... this is what we've always used where I work and learned to weld - so I never knew any different...)
Reply:When I first read your remark about Argon not being correct for mild steel I thought you were Mig welding  (Argon/CO2)  To the best of my knowledge pure Argon is what most guys use with TIG and mild steel?  Not really sure how the tubes are stacked as you say but if im correct your talking about the gap caused by the radius on the edge of the square tube?  You can get square tube with a small radius and not have that gap......To fill the gap you need more filler....More filler =  3/32 and you leave it in the puddle and run it with more heat......Pictures would help .....  Miller Dynasty 350Twenty Six HammersThree Crow BarsBig Rock
Reply:try 1/16" tungsten, lay wire technique, direct most of your heat toward the curved corner, not the edge.
Reply:thanks for all of your suggestions so far, would be happy to see more too!  I am also wondering if I am encountering some variance in the tube corner radius that is making the fit slightly different at each joint. I can definitely see (looking from the ends) some variance in the overall shapes of the tube - some of the sides are curved (in or out) and some pieces the tube is either more or less square. Need to control for clamping pressure when I am cutting in the cold saw, but I'm thinking that slight variances in material specs are generally part of the overall picture, and part of increasing skill is the ability to account for this and still make it come out right.SO... let's say for the sake of discussion that at times there is a variance in the tube corner radius, which translates into changing the gap size - and shape - at the joint. What I'm looking for is how to THINK about this variance in terms of how to respond to it; I.E. bigger gap = different torch angle/movement/more heat/less heat/speed/filler etc etc etc. Maybe I just need to do it until it comes out the way I want it... But would love not to waste gas/time/material to the extent that I can avoid throwing s*** at the wall to see what sticks...
Reply:That's what I said when I replied to your question.......There are different edge profiles on square tubing.......You need to make it clean to your steel salesman what you want...  Miller Dynasty 350Twenty Six HammersThree Crow BarsBig Rock
Reply:Originally Posted by peanutjarthanks for all of your suggestions so far, would be happy to see more too!  I am also wondering if I am encountering some variance in the tube corner radius that is making the fit slightly different at each joint. I can definitely see (looking from the ends) some variance in the overall shapes of the tube - some of the sides are curved (in or out) and some pieces the tube is either more or less square. Need to control for clamping pressure when I am cutting in the cold saw, but I'm thinking that slight variances in material specs are generally part of the overall picture, and part of increasing skill is the ability to account for this and still make it come out right.SO... let's say for the sake of discussion that at times there is a variance in the tube corner radius, which translates into changing the gap size - and shape - at the joint. What I'm looking for is how to THINK about this variance in terms of how to respond to it; I.E. bigger gap = different torch angle/movement/more heat/less heat/speed/filler etc etc etc. Maybe I just need to do it until it comes out the way I want it... But would love not to waste gas/time/material to the extent that I can avoid throwing s*** at the wall to see what sticks...
Reply:Post Pictures so we can see what your doing?  Miller Dynasty 350Twenty Six HammersThree Crow BarsBig Rock