Noob TIG sheet metal questions
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  1. #1
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    Jul 2018
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    Noob TIG sheet metal questions

    Hi All,

    I'm learning TIG, I'm starting to get better at thicker steel, but still having a hard time with thin sheet metal. I'm going to be welding a lot of auto body panels, so I want to make sure I'm doing it correctly before I start on my car.

    I've got an AHP Alpha TIG 200x, 1/16" lanthinated electrode, straight DC at 30A with foot pedal. I'm practicing with 22 guage mild steel, and my problem is mostly burn through. I'm working without any backing, as when I get to real work (body panels), there isn't any practical way to use backing. I seem to be a lot more proficient with the lanthinated vs. the thoriated electrodes.

    My questions are what are your thoughts on using using the pulser vs. setting the amperage lower. What's the advantage of the pulser, and what kinds of situation is the pulser best used in.

    How wide should the puddle be for 22 guage butt welds?

    Are there any tell-tale signs of when the puddle will burn through, i.e. when to back off amperage?

    I'm sharpening to electrode to a fairly sharp tip, about 2-3 electrode diameters because I'm trying to get the arc to diffuse out a bit, and not put so much heat focused in a tiny spot.

    For 18-20 guage auto body panels, what is the prefered TIG settings, in terms of amperage, electrode/rod size, pulser settings, etc..

    I'll also be doign some overhead welds, so I'd like to get really proficient before I start on those.

    Thanks

  2. #2
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    Re: Noob TIG sheet metal questions

    If you are doing tight (inside) fillet welds, turn off the pulse to concentrate the arc in the root. The outside type welds perform nicely with pulse.

    Personally you should try to master without pulse, then gradually add. My preferred pulse for thin sheet-outside corners or groove is 45% main amps time, 25% background amps value, and 150pps.

    Main amps is really turn down the amps until it won't melt the metal anymore, then edge it up until you can weld, then stop with postflow until it is cool enough to weld again. .030" diameter Esab/EasyGrind wire is your friend for panel work, but not framework. I use it for gunsmithing when the customer is filing or stoneing a detail.
    Weld like a "WELDOR", not a wel-"DERR"
    MillerDynasty700DX,Dynasty350DX3ea,Dynasty200DX,Th ermalArc400GTSW,LincolnSW2002ea., MillerMatic350P,MillerMatic200withspoolgun,MKCobra Mig260,Lincoln SP-170T,PlasmaCam/Hypertherm1250,HFProTig3ea.

  3. #3
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    Noob TIG sheet metal questions

    These are 22 gauge mild steel, straight DC 30 amps, 1/16” lanthinated tungsten, 1/16” filler rod.

    The faces are starting to look a bit better, but look how horrible the back sides are.

    What can I do to put less heat in so I don’t have so much melting on the back side, but still enough heat to form a puddle.

    I’ve tried the pulser, at 80 amp, 50 hz, 30% on, base of 30% of peak. Didn’t have much luck there, didn’t seem to have enough heat.

    I’m also having a real hard time seeing the puddle, and not really sure how to tell if it’s too hot and how to tell when I should move.

    What can I do to improve these welds?




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    Last edited by Andy Somogyi; 07-11-2018 at 09:49 PM.

  4. #4
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    Re: Noob TIG sheet metal questions

    In my opinion, your welds are way too big.
    My name's not Jim....

  5. #5
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    Re: Noob TIG sheet metal questions

    Quote Originally Posted by Boostinjdm View Post
    In my opinion, your welds are way too big.
    This one here, well at least half of it is about the best, and it’s 0.2” wide.

    To get the welds smaller, should I turn the amps down and try to hold a closer arc, or should I try to use the pulser?





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  6. #6
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    Re: Noob TIG sheet metal questions

    Tighter arc and smaller filler. I'd go for .035 mig wire cuz that's what I have handy.
    My name's not Jim....

  7. #7
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    Re: Noob TIG sheet metal questions

    Going to smaller filler will help tremendously. I would use 0.030" or 0.035" MIG wire for that. MIG wire works much better if you straighten it. My method is to secure one end of the piece of wire I'm going to use in a vise, then use safety wire pliers to twist from the other end. Putting a couple twists in it makes it straight enough you can feed easily by hand.

    With 1/16" rod, by the time you've gotten enough heat in the joint to melt the wire, you're right on the verge of blowing through. Smaller wire will also make for less distortion. I tend to run 0.045" rod for everything less than 1/8" or so thick, and drop down to straightened MIG wire for 18 gauge and lighter.

  8. #8
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    Re: Noob TIG sheet metal questions

    Quote Originally Posted by Graham08 View Post
    Going to smaller filler will help tremendously.

    With 1/16" rod, by the time you've gotten enough heat in the joint to melt the wire, you're right on the verge of blowing through.
    Thanks, that makes sense, just ordered some 0.035 wire.

    Once I get this figured out, I’m going to be working on mostly 18 and 20 gauge. My thinking is if I learn on thin 22 gauge and get good at it, the real stuff at 20 should be easy.

    Now I just need to figure out how to keep the arc short enough without dipping.




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  9. #9
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    Re: Noob TIG sheet metal questions

    Cram that rod in a chill the puddle, then haul azz. Basically you are not moving fast enough. Smaller wire just makes it harder to fill and move fast. If it were me I would not go smaller than .045 wire. In fact I don't even have smaller than that.

    Tight arc, cram and jam. Judging by the underside your welds are overheating. But overall your welds do not look too bad.
    Weld like a "WELDOR", not a wel-"DERR"
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  10. #10
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    Re: Noob TIG sheet metal questions

    It’s improved slightly.

    This is using 0.035 wire, 1/16 tungsten needle tip, pulse on, 3 pulse per second, 40A peak, 10% background, 30% on.

    The pulse seems to work rather well, I dab about every 3rd pulse.

    I tacked in the middle and welded in 4 sections to minimize warpage.

    For tacking, what I found was start the arc on the wire, let it ball up, direct the arc to the ball until it heats the surrounding metal and wets, about 2-3 seconds per tack.

    Also, I start the initial section off to the side slightly and steer the puddle onto the gap between the pieces. This way, I prevent burning the edges at the start of a section.

    Do you guys think I have too much penetrating looking at the backside. I think I can probably go faster, just need some more practice, but going faster I think should clean up the backside some.





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  11. #11
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    Re: Noob TIG sheet metal questions

    Getting better!

    I know that in theory learning on 22 gauge should make you better at 18 and 20, but you might have better success going the other way. Once you get the hang of it on 18 gauge, going thinner should just take some adjustments to your technique.

    I second the move faster comments. It's easier said than done, though.

    How dark is your welding lens? Dropping down to a 9 or an 8 would help you see what's going on better. TIG at 30 amps is a lot different than blasting away at 150...

  12. #12
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    Re: Noob TIG sheet metal questions

    Quote Originally Posted by Graham08 View Post
    Getting better!

    I know that in theory learning on 22 gauge should make you better at 18 and 20, but you might have better success going the other way. Once you get the hang of it on 18 gauge, going thinner should just take some adjustments to your technique.

    I second the move faster comments. It's easier said than done, though.

    How dark is your welding lens? Dropping down to a 9 or an 8 would help you see what's going on better. TIG at 30 amps is a lot different than blasting away at 150...
    I also have an ulterior motive for 22 gauge: I’m cheap, and have a bunch of it lying around

    I know I need A LOT more practice to get a feel to move faster. I tell you, learning to TIG is one of the hardest things I’ve ever done, definitely as challenging as my physics PhD qualifying exam.

    I’ve got a cheap auto darkening helmet set on the brightest setting. Finding a good position to watch the arc is not easy either, probably because my eyes aren’t all that great. I’m using a #7 gas lens, and use 1 cup diameter stick out, which does help a lot to see the arc.


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  13. #13
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    Re: Noob TIG sheet metal questions

    I think you are right, probably go faster. You are dipping every 3rd pulse at 3pps, so that is 1 dip per second. That is a little too slow for me.

    Once again, bigger wire will chill the puddle better especially when you learn to plump up the bead with it. I am guessing you are dribbling the wire in instead of sliding/craming it into the leading edge?

    Back side looks ok as well but I would prefer to see some push through instead of melty suckback. Again cramming the rod in with generous amps and speed would give you push through. I would need some anti depressants if I had to use .035" on 22 gauge.
    Weld like a "WELDOR", not a wel-"DERR"
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  14. #14
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    Re: Noob TIG sheet metal questions

    Quote Originally Posted by shovelon View Post
    I think you are right, probably go faster. You are dipping every 3rd pulse at 3pps, so that is 1 dip per second. That is a little too slow for me.

    Once again, bigger wire will chill the puddle better especially when you learn to plump up the bead with it. I am guessing you are dribbling the wire in instead of sliding/craming it into the leading edge?

    Back side looks ok as well but I would prefer to see some push through instead of melty suckback. Again cramming the rod in with generous amps and speed would give you push through. I would need some anti depressants if I had to use .035" on 22 gauge.
    I’m I guess you’d call it dribbling or dabbing into the puddle leading edge, I’m trying to stay far from the electrode, as I really hate jamming the electrode with the filler wire. Basically I touch the filler wire to or near the puddle leading edge until the wire balls up and wets into the puddle.

    The puddle itself is about .070” dia, and I don’t think I’m good enough to aim for a puddle that small without touching the electrode.

    I’ll give a thicker wire a try, I’ll twist together a pair of .035


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  15. #15
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    Re: Noob TIG sheet metal questions

    Quote Originally Posted by Andy Somogyi View Post
    I’m I guess you’d call it dribbling or dabbing into the puddle leading edge, I’m trying to stay far from the electrode, as I really hate jamming the electrode with the filler wire. Basically I touch the filler wire to or near the puddle leading edge until the wire balls up and wets into the puddle.

    The puddle itself is about .070” dia, and I don’t think I’m good enough to aim for a puddle that small without touching the electrode.

    I’ll give a thicker wire a try, I’ll twist together a pair of .035


    Sent from my iPad using Tapatalk Pro
    Yes, that is the idea. Figure your routine is stomp the pedal to get your puddle, then cram the rod in from the leading edge to plump up the puddle while lifting your electrode a tad to get out of the way, Then with a plumped puddle retract your wire while grabbing a bit more to cram in later, slide your electrode with a tight arc to the front of the puddle into the root to achieve full wetting to the root, and finally cram that rod/wire that you grabbed with your fingers to plump the bead/puddle again. Repeat as necessary and the routing becomes natural. Cram and jam is what I call it.

    For your information that is how you do "Stack-O-Dimes". I just do it to aerospace standards. After a while you get tiresome of pissing around with tiny wire and learn how to delicately feed thicker wire. It actually chills the puddle more so you may have to input more amps, but that is ok with me because now I can go faster and make more money. Just today I had an aerospace engineer question my usage of 3/32" 4043 wire when they advise .062" wire. No problem I says, because per essential variables I am allowed to go +/- 1/16". I am also allowed to change the filler to 4943 alloy because it is also an F23 filler and the essential variables allow me to do choose any filler in the same filler group. Nope, mr. engineer did not like that as it made him do more work to verify my assertions.
    Weld like a "WELDOR", not a wel-"DERR"
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