Undercut with TIG

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I have been practicing TIG a lot lately and I am having some problems with undercut on the top side of the bead.I am welding .083 MS 2"x3" square tubing.  1/16" orange tung., 110 Amps, 1/16" Filler.  The weld is a fillet weld and I am positioned as close to the middle of both parts and I can tell.I have I have tried less heat and it appears to still be there.  Can anyone give me some pointers?  Do I need more filler?  I am dipping it into the end of the puddle and moving about 1/8" at a time.  I just cannot figure this out.Thanks in advance!Build a Barstool Racer at BarFlyRacers.com!
Reply:less heat more filler.David Edit, I think a contaminated tungsten under cutts too.Real world weldin.  When I grow up I want to be a tig weldor.
Reply:did you clean the metal first ?ChuckASME Pressure Vessel welder
Reply:Yes, I hit the metal with a flap disc, and the acetone.  The metal is very clean, the arc is stable the tung. is clean and sharp.I thought the proper amount of filler was to dip the tip of the rod in the puddle, but maybe I need to jam a little more...  I dunno.....I have never been able to find any reference as to the amount of filler / dipping technique.  I even have a video by Ron Cove ll and he does not explain it.  I guess it is one of the TIG secrets / mysteries you need to learn for yourself...Build a Barstool Racer at BarFlyRacers.com!
Reply:Think more of a STICK than a dip.DavidReal world weldin.  When I grow up I want to be a tig weldor.
Reply:Concentrate on the bead at the top where the problem exists..More filler twards the top of the puddle..Kinda hard to explane..but easy enough to figure out.....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:Hi Zap!So are you saying to not just stick the filling in the puddle, but to aim it towards the problem areas?  I am asking because it is hard to tell you have undercut until you are finished.  Know what I mean?From what I have read and learned, when you dip the rod into the puddle, the puddle will take what it needs.  Thanks!Build a Barstool Racer at BarFlyRacers.com!
Reply:This talk of "undercut" is confusing.... There seems to be at least 2 definitions for this floating around. Undercut can only mean one thing, what's it gonna be?Miller EconotigCutmaster 38Yes ma'am, that IS a screwdriver in my pocket!
Reply:So are you saying to not just stick the filling in the puddle, but to aim it towards the problem areas?
Reply:Joe,What I mean by undercut is near the top of the weld bead, the base metal is burned in to where there is a visible lip and not weld.  I think I will try using more filler because my heat is very minimal and I am getting blistering on the back side and thats it.  If I use less heat, I think the puddle will be too small and the weld will be cold.I will see what happens tomrrow...Build a Barstool Racer at BarFlyRacers.com!
Reply:Does anybody recommed the "laywire" technique for this.  What I mean is with MS you can get away with laying the filler in the root of the joint and welding over it with your normal motion.  This technique is detailed in the Hobart Bros. Institute welding manuals and helped me get my torch movement down before adding the complication of the dip.  Also, you might have too much push angle.  If you have room, you might try aiming the torch more down into the root instead of at the very front of the puddle.  I'm in no way a pro, but this stuff works for me.  I'm hoping some of the more gifted folks around here will set me straight if this is bad advice.
Reply:Keeping a short arc (the size of the tungsten) helps too.  You have more control.DavidReal world weldin.  When I grow up I want to be a tig weldor.
Reply:When I first posted my TIG welds ZAP mentioned I had undercut. After I was told what the undercut was and some pointers from poeple here, I was able to solve the problem by;1. Less heat.2. More filler.3. SLOW down. It seems that slowing down made the biggest difference.
Reply:Originally Posted by David RKeeping a short arc (the size of the tungsten) helps too.  You have more control.David
Reply:After doing some thinking I had an idea I may be also having some arc problems due the the way I am grinding my tungsten.  I was using one of those utility sharpeners by Task Force which has a find grit wheel, but turns very slow compared to a grinder.So I took the utility sharpener back and got a bench grinder for $5.00 more and picked up a fine grinding wheel for it.Maybe due to the slow rotating speed of the utility sharpener and me using my drill to turn the tungsten, I may have been getting some radial lines in the tip.  The arc appeared good to me, but then what do I know I am new to TIG, maybe I was getting some additional arc off the side of the tungsten causing the undercut.I will find out shortly if it made any difference.Thanks!Build a Barstool Racer at BarFlyRacers.com!
Reply:Originally Posted by o.c.d.When I first posted my TIG welds ZAP mentioned I had undercut. After I was told what the undercut was and some pointers from poeple here, I was able to solve the problem by;1. Less heat.2. More filler.3. SLOW down. It seems that slowing down made the biggest difference.
Reply:If you slow down and use less heat, the heat input to the plate will be the same. You will still get blistering on the back side.   I like a tig bead that looks like I did it with stick.What do you do for undercutting with stick?  Less heat, slow down.DavidReal world weldin.  When I grow up I want to be a tig weldor.
Reply:Personnally I beleive tig is the easiest process to learn as you have the most control over it.   Remember a weld pool is liquid, water don't run up hill, so feed you wire to the top of the POOL.   The plug is at the bottom of the bath for a reason I'd rather be hunting........USE ENOUGH HEAT.......Drifting around Aussie welding more pipe up, for something different.....wanting to get home.
Reply:malich,how about a photo of the undercut?  It would go a long way in giving you meaningful feedback.
Reply:Ok, I found out what was causing the undercut.  I was using a gas lens with about 1/4" stickout on the electrode.  This was also causing the back side of the base metal to burn real bad to where the metal would fail.I changed to a 3/8" standand cup and all the under cut and burn on the back side went right away.  My weld bead quality changed a lot and looks poor now compared to using the gas lens.From what I have read, stainless weld beads look a lot better than a steel bead.  Can anyone post some photos of acceptable TIG weld beads on steel?As for the gas lens, I had the regulator set at 12psi, maybe I need to go down to 8psi, not sure or a longer stick out.I was able to produce a very nice weld bead on a butt joint with the standard 3/8 cup, but when I tried the fillet weld, ugly.  The look like they are cold and not smooth, but the blistering on the back sides tells me the heat was there.  I burned up over 9' of wire today.  Got lots more to go.Thanks in advance!Build a Barstool Racer at BarFlyRacers.com!
Reply:1/4" with a gas lens is no big deal..I have had them out 3/8 and beyond!Hmmmm9 feet of wire?I probably went thru 150-200 feet from 10:00 to 3.....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:It makes sense that changing from a gas lens to a standard collet would reduce the quality of your weld appearance, but I can't think why it would tend to affect undercut, or why should it affect the backside.  Something else is going on here.
Reply:Zap,What kind of PSI where you running on the regulator with the 3/8" stickout?  I know it has to have something to do with PSI, because I only changed from the gas lens to the standard 3/8" cup and it was like night and day.Also, I noticed when the gas is flowing, the regulator shows a lower flow than when it is not flowing.  How should I set PSI when the gas is flowing or off?Thanks!Build a Barstool Racer at BarFlyRacers.com!
Reply:Hey Pulser,I left all the machine settings the same, just went to a standard cup (no more gas lens) and bam!  Problems gone.  Do you want me to show you a photo of the front a basksides?Build a Barstool Racer at BarFlyRacers.com!
Reply:I run mine between 8 to 10 S.F.C.H. with 5 sec post purge..All the time..Step on the pedal and adjust the regulator with the gas flowing..You'll see..Its all just practice I guess.....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.Here are some photos from todays welding.  The photo names describe the welds with or without the gas lens and front and back side.Hope this helps...Thanks! Attached ImagesBuild a Barstool Racer at BarFlyRacers.com!
Reply:And you never touched the machine...?...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:Nope!  No changes what so ever to the machine.  I kept thinking about what I was doing different than most and Ron Covell in his video that I have and it was the gas lens.  All I did was put a #5 cup on and that was it. Same tungsten, amps and gas flow. I always keep the tungsten clean and sharp, same stickout and angle.  I have run many beads with the gas lens and the same problem on every one.  When I changed the cup and removed the has lens it was the first time I did not have under cut or the burn on the back side.I cannot explain it, but I am thinking the gas pressure from the gas lens maybe was doing something to the arc and I need a lower flow rate.Build a Barstool Racer at BarFlyRacers.com!
Reply:Beats me...But between you and I?It really should not matter..I very rarely adjust my gas flow rate..Oh well what works for you..Run with it!...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:I will do some more testing next week with the gas lens and see what I can some up with.How about the weld bead quality?  It looks pretty good to me compared to when I started...  I am looking for some professional opinions so I have somthing to work torwads.Thanks!Build a Barstool Racer at BarFlyRacers.com!
Reply:What you might try is backing the heat off and use a smaller diameter filler. Then dont dab at the puddle, push it in. Feed it. Watch the back side of the puddle rise to create the ripple then lift the  filler toward the cup. Move forward, Repeat. If you dont lift the filler toward the cup using smaller filler you will ball the end if it. Stop and cut it off.These are the hardest things for me to remember. I am self taught oxy acet welding and I taught myself badly. Now I'm having to relearn. I was jabbing the filler not feeding it.Slow down, watch the heat feed the puddle.mm135HTP Invertig 201 With water cooler9" Southbend LatheLots of hand tools.
Reply:Hi Papasloan,Thanks for the post.  Your idea to watch the puddle on the back side makes sense.  I was looking at some TIG welds someone else had done, and I figured the only way he could have filled them like he did was to watch the back side also.I have never heard of anyone mentioning to watch the backside before, but it makes sense because you need to see how the weld is filling and you cannot do that from just the front an guessing how much filler to feed.Thanks!Build a Barstool Racer at BarFlyRacers.com!
Reply:I've said many times you need to..Look in front of the puddle..At the puddle...Behind the puddle..All at the same time.. And thats enough to befuddle ya......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:Originally Posted by zapster I've said many times you need to..Look in front of the puddle..At the puddle...Behind the puddle..All at the same time.. And thats enough to befuddle ya......zap!