Tig weld comments?

admin

Finally have the TIG machine at the college dialed in pretty well. It's an old Airco 300A stick/tig machine (same as Miller 330BP). Had to crank up the high frequency intensity a lot to get starts to work better (as posted in a different thread).Did some welding on 1/8" mild steel, edges cleaned of mill scale on a belt sander, used uncoated rod (unknown exact specs) along with some ER70S, Argon gas, probably 105A or so (no meters on the machine to be sure):Working on getting larger beads. Should I be? Should I expect anything remotely like a MIG weld bead when doing TIG work? The bumps at the end of some of the beads was from not letting the pool melt when I finished before shutting the torch off:The smoky part is where I stopped to get a better hold on the rod. Not sure why it smoked as I was careful to dwell over the bead during cooldown:
Reply:I think the width of your bead should depend on the thickness of the stock you're welding.  I.e., the thicker the base material, the wider the bead.  Another way of looking at is that the width of the bead is in proportion to the amps required for a given thickness of steel. So, the more amps, the wider the bead.  This analogy works up the the point that multiple passes are required.ScottMiller XMT 350 CC/CV w/gas solenoid opt.Miller S-22A wirefeederBernard 400A "Q" gunMiller Spoolmatic 30A / WC-24C-K 200A torch/gas lensWeldcraft WC-18 watercooled torchHypertherm Powermax 30Victor O/A
Reply:Those welds look pretty good.I used to have a Airco 300.  It is a good machine, it should last awhile.The Welder Shop has great deals and reviews on Hobart, Miller and Lincoln Welders.
Reply:Looks really good!  Only suggestion I'd have is to clean more of the scale off.  From what you said in your post I get the impression you just ground the very edges - next time grind all the scale within 1/4" of where your weld bead will be.  Looking at the pics you were still laying the bead over scale.
Reply:I sanded back about 1/8" from the edge. I'll sand back further next class session.
Reply:Looks very good, nice consistent bead width and ripple pattern.
Reply:Ok, it just looked like there was still some scale under your welds.  Maybe you just didn't sand deep enough to get through it all - sometimes it can be hard to get off there.  When you're deep enough it will be smooth and a brighter metallic color than the scale.
Reply:not too shabby! Looks good. Scale and TIG BAD! Those old machines had adjustable HF on DC startup? Please elaborate......Older equip. is cool....Yeah, yeah, I know you are a weldor too. But, are you a good one?
Reply:I think its lookin good.   I get black spots like that when I dunk the electrode.I don't have to say clean it better DavidReal world weldin.  When I grow up I want to be a tig weldor.
Reply:This particular machine has Start/Continuous/Off high frequency, with intensity control. I checked the gap on the high frequency gaps and they are set properly, still doesn't seem to have as much oomph starting as some of the other machines out there, but it's working well enough.The torch on it has a rather thick rubber covered cable setup and really wears on the wrist after a while. Tossing the cable over a shoulder just makes the torch that much harder to manage. Definitely not optimal.
Reply:I thinks it looks great..Clean clean..well you know..I like the tie-offs..Very nice for first timers.....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:What is a tie-off?Sample TIG weld from tonight on thin sheet steel. Starting function is still very spotty on the machine. With a hot tungsten, HF jumps a large gap. When cold, it's back down to 1/16" or so. I was able to observe the spark gaps and there are large number of sparks jumping the spark gap (in the machine).
Reply:Originally Posted by ttyR2What is a tie-off?
Reply:Those look very nice, seems like class is working. Nice work.ESAB Tigmaster 252 Miller MillerMatic 252 migLots and Lots of toolsNot much but a startWoohooo I just got a bandsaw given to me. So bandsaw nowNow a free hydraulic press