So I just started welding with Tig and I'm havin alot of trouble on lap joints. 11 guage a36 steel, 1/16 2%lanth and 1/16 filler. Runnin about 85-90 amps with a foot pedal.
I can get a good bead all the way across but the weld is very concave. I'm keepin the torch about 1/32 pointed at the bottom plate, but my arc keeps wantin to jump to the top plate and melt the top plate into the puddle. I got a real fine point tip on my tungsten but after i get about half the plate welded the puddle just gets out of control, like I need to lay off on the pedal some.
My main question is what do I do when the arc wants to jump to the top plate? Should I lay off the pedal and adjust the torch to the bottom? Or stop completely and readjust myself and the plate.
I don't know what the rest will say but when that happens to me I go to 3/32 and blunt the tip slightly. I still use the 1/16 rod. I'm pretty new with TIG too so there's probably something better. I also walk the cup in 1/2 circle motions but I think that's mainly a hold over from my MIG experience. Seems to work thoughkermdawg wrote:So I just started welding with Tig and I'm havin alot of trouble on lap joints. 11 guage a36 steel, 1/16 2%lanth and 1/16 filler. Runnin about 85-90 amps with a foot pedal.
I can get a good bead all the way across but the weld is very concave. I'm keepin the torch about 1/32 pointed at the bottom plate, but my arc keeps wantin to jump to the top plate and melt the top plate into the puddle. I got a real fine point tip on my tungsten but after i get about half the plate welded the puddle just gets out of control, like I need to lay off on the pedal some.
My main question is what do I do when the arc wants to jump to the top plate? Should I lay off the pedal and adjust the torch to the bottom? Or stop completely and readjust myself and the plate.
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kermdawg
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More or less set on usin the 1/16 tungsten. I thought about walkin the cup too but with such thin guage material I thought there would be a better way. Like I said I can get a good bead goin but about halfway down the plate the arc starts to want to jump to the top plate and the top plate just melts and I lose the pool on the bottom plate. I mean I can stop and restart but it leaves a real nasty lookin gouge out of the top plate in the middle of the weld and it looks like crap 
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Generally speaking, running hotter, and at a faster travel speed gives you less overall heat input into the work. This will mean you won't need to taper off the heat as much toward the end of your weld bead. You might consider using more amps and traveling faster, so as to have a better shot at "outrunning the heat".
Other things you can try - If you are having trouble tapering the heat, turn down the max current setting so you run your footpedal at a more "wide open throttle" position. This will give you more range to feather it down on the low end. Also, to focus the heat better right at the tip of your tungsten, try holding a tighter arc. And if your machine supports high frequency pulsing, run it.
11 gauge steel would mean .11" thick. If you go by the 1 amp per thousandth of thickness rule, it would call for 110 amps. The miller TIG welding calculator calls for a steel 1/8" (.125") lap weld, to use 100-140 amps, a 1/16" tungsten, and 3/32" filler rod. The thicker filler rod called for in the miller calculator may be a good idea because it will help you to feed the rod faster, which could help you to use more heat and to move your torch faster.
Other things you can try - If you are having trouble tapering the heat, turn down the max current setting so you run your footpedal at a more "wide open throttle" position. This will give you more range to feather it down on the low end. Also, to focus the heat better right at the tip of your tungsten, try holding a tighter arc. And if your machine supports high frequency pulsing, run it.
11 gauge steel would mean .11" thick. If you go by the 1 amp per thousandth of thickness rule, it would call for 110 amps. The miller TIG welding calculator calls for a steel 1/8" (.125") lap weld, to use 100-140 amps, a 1/16" tungsten, and 3/32" filler rod. The thicker filler rod called for in the miller calculator may be a good idea because it will help you to feed the rod faster, which could help you to use more heat and to move your torch faster.
kermdawg
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Thanks for the advice. I was kinda thinkin I needed to turn it up 10 amps or so but I was kinda hesitant to do so. Then again I'm also going to try to dum it down a bit to run more wide open on the foot pedal. Ill let ya know how it turns out in a few days when I get a chance to try again.
Thanks again.
Thanks again.
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Hey Kermdog, you didn't mention what type of machine your using, but I'll assume it's a transformer based, non pulsing unit. The problem is that you can nestle in nice and tight in the fillet, but if you control your heat as such the rod adds cool the puddle too much, and you cannot get enough of a bead profile built up, ie rod material, ..... right? Resulting in the concave profile. If you add more heat things happen too fast and the arc cone washes up and errodes the top edge. So, your question about stopping is no, .... but you DO have to back off on the heat ..... fast! In order to catch the wash over. That's what the pedal is for ..... to allow you to adapt as your welding. You can back way off, pause to regroup for a second and continue.
I know that doesn't answer your question yet, but it will help to understand that the pedal is part of the answer. Like my Dad told me as he was giving me flight instruction years ago, " don't think of it as your butt being strapped to the airplane, and your just along for the ride, ....... think of it as the aircraft is strapped to YOUR behind, ... and make it do what YOU want to do ". Sorry for the poor analogy, but you get what I'm sayin. The torch, tungsten, pedal, settings, etc. are all there for you to make the weld do what YOU want, not the opposite. ( with practice of course ).
Now some things you can try and play around with till you find what works for you. ( Are ya pickin up on what i'm puttin down? - There are lot's of ways to skin a cat! ) Ok, so first for that thickness material I'd go with 3/32 tungsten. 80 or 90 percent of most folks welding will best be done with that size. Next, on that joint type, on steel, I would personaly manualy pulse the foot pedal, in a rythmic fashion. Adding your rod as you bring on the heat of each pulse. ( there is a slight difference in timing that you just have to try it to see it, ..... I cannot adequately decribe that which is a subtle learned thing ). You will in part be controlling the heat with your rod, .... as you stuff it in there you will be cooling the puddle thus controlling the width or wash of the bead, and as well getting the build up you require. Each pulse now can be fairly aggressive once you practice a bit and gain confidence, and you will begin to see and "feel" a correlation between the adding of pedal heat, and the cooling of the rod adds. Eventually they will become almost seamless, .... with LOTS of practice. Also try angling your tungsten more towards the flat bottom piece, and modulating each pulse evenly, perhaps adding your rod slightly from the top, .... protecting the edge. Alternatively you can add more from the bottom and wash or PUSH each pulse/add to a precise point up the vertical face of the joint. Even if you just lightly lap the edge on each pulse, as long as you are consistent it will still look fine. In fact thats another way to tackle it, ...... go ahead and just crest the top edge, but do it evenly along the weld, as if you engulfed the sharp angle and replaced it with a uniformly overlapped bead pattern ...... but only barely altering the height of the lap. Again it's about controlling the arc and the puddle, however you have to do it! Hope I gave ya a few ideas to play around with.
Best of Luck!
I know that doesn't answer your question yet, but it will help to understand that the pedal is part of the answer. Like my Dad told me as he was giving me flight instruction years ago, " don't think of it as your butt being strapped to the airplane, and your just along for the ride, ....... think of it as the aircraft is strapped to YOUR behind, ... and make it do what YOU want to do ". Sorry for the poor analogy, but you get what I'm sayin. The torch, tungsten, pedal, settings, etc. are all there for you to make the weld do what YOU want, not the opposite. ( with practice of course ).
Now some things you can try and play around with till you find what works for you. ( Are ya pickin up on what i'm puttin down? - There are lot's of ways to skin a cat! ) Ok, so first for that thickness material I'd go with 3/32 tungsten. 80 or 90 percent of most folks welding will best be done with that size. Next, on that joint type, on steel, I would personaly manualy pulse the foot pedal, in a rythmic fashion. Adding your rod as you bring on the heat of each pulse. ( there is a slight difference in timing that you just have to try it to see it, ..... I cannot adequately decribe that which is a subtle learned thing ). You will in part be controlling the heat with your rod, .... as you stuff it in there you will be cooling the puddle thus controlling the width or wash of the bead, and as well getting the build up you require. Each pulse now can be fairly aggressive once you practice a bit and gain confidence, and you will begin to see and "feel" a correlation between the adding of pedal heat, and the cooling of the rod adds. Eventually they will become almost seamless, .... with LOTS of practice. Also try angling your tungsten more towards the flat bottom piece, and modulating each pulse evenly, perhaps adding your rod slightly from the top, .... protecting the edge. Alternatively you can add more from the bottom and wash or PUSH each pulse/add to a precise point up the vertical face of the joint. Even if you just lightly lap the edge on each pulse, as long as you are consistent it will still look fine. In fact thats another way to tackle it, ...... go ahead and just crest the top edge, but do it evenly along the weld, as if you engulfed the sharp angle and replaced it with a uniformly overlapped bead pattern ...... but only barely altering the height of the lap. Again it's about controlling the arc and the puddle, however you have to do it! Hope I gave ya a few ideas to play around with.
Best of Luck!
kermdawg
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Thanks for the reply Track. Runnin a Lincoln Precision Tig 225, and it does have a pulser on it, I've never messed around with it though. Guess I could give it a shot.
That last part where you were talkin about meltin the edge of the top plate into the bead, thats what I was goin for/hopin for.
That last part where you were talkin about meltin the edge of the top plate into the bead, thats what I was goin for/hopin for.
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kermdawg
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Just an update-I got an 85 out of 100 on my 11 guage lap joint. Not what I was goin for, but I'll take it. I ran about 10 before I got something that good. I guess everyone has their own problems with certain joints eh?
I did manage to get a nice wash on the top of it without undercuttin it, and I got a flat/convex bead the whole way down. Main thing I god dingged on was a little over penetration on the bottom side, and some contamination on my 2 restarts. And the last 2 inchs were a little hot.
I ran at like 100 amps, bout 3/4 pedal and had MUCh better results meltin the top plate to the bottom plate. Like I said, just a little to much penetration at the end when the plates got hot.
Last thing, I played with the pulser a little bit. Same amperage, pedal mashed. I couldnt really get a stack of dimes, my bead was flat with the plate and burned through.(this is just a stringer on plate). I fed filler on the pulse and moved on the lower end. Kept a nice puddle the whole way, and I it seemed like I fed alot of wire into the puddle, more than usual. Anything I'm doin wrong on that?
I did manage to get a nice wash on the top of it without undercuttin it, and I got a flat/convex bead the whole way down. Main thing I god dingged on was a little over penetration on the bottom side, and some contamination on my 2 restarts. And the last 2 inchs were a little hot.
I ran at like 100 amps, bout 3/4 pedal and had MUCh better results meltin the top plate to the bottom plate. Like I said, just a little to much penetration at the end when the plates got hot.
Last thing, I played with the pulser a little bit. Same amperage, pedal mashed. I couldnt really get a stack of dimes, my bead was flat with the plate and burned through.(this is just a stringer on plate). I fed filler on the pulse and moved on the lower end. Kept a nice puddle the whole way, and I it seemed like I fed alot of wire into the puddle, more than usual. Anything I'm doin wrong on that?
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Hey Kerm, .... Congrats on the score ..... not bad. As far as the pulsing, just remember that anytime you "mash" the pedal you are relying on whatever settings you have made on the current, background current, pulse time on etc. It would be as if you were in 2T/4T mode with a remote torch control. You will have had to tweak and dial in your settings on some identical scrap practice pieces to the point of really being dialed in. If your doing a production run of parts it can be very benificial resulting in very consistant uniform welds. But in many cases you may be doing only a few or even one piece, so even with the pulser on, varying the pedal may still be required to control the overall heat input to the weld, and let the pulse do it's thing in that context.
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Ya I'm startin to get the old practice makes perfect addage, especially when your talkin about gettin dialed in. I'm startin to get alot better control of the foot pedal. It was a bit tricky for me but its comin around. Startin to be able to notice 5 amps up or down too.
So far I turned in three assignments and got two 89's and an 85, which really bums me out honestly cause I want to be 95 or above. I know you dont pass a cert test with an 85, or even a 95 really. So I'm just tryin to get all the seat time I can for now.
So far I turned in three assignments and got two 89's and an 85, which really bums me out honestly cause I want to be 95 or above. I know you dont pass a cert test with an 85, or even a 95 really. So I'm just tryin to get all the seat time I can for now.
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