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  1. #61
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    I'll see what I've got lying around in the offcut pile with welds that long in that thickness. So your machine is set at about 57A. 70A for the fillets, right? I'll try those settings and try what I'd use for comparison. If I've got time.

    Re flash rust, I just touch it up with the flap disc again. If it's in a corner, a piece of sandpaper and then blow it clean. Or you can try something chemical like an oil to prevent rust and then clean it off before welding.

  2. #62
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    thanks mate ill try some lanolin to stop the rust

  3. #63
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    While I think it is great that you are doing your absolute best to weld on clean steel, don't be too concerned about a little surface rust for what you are doing. Tig likes clean material, but it will handle a little surface rust without too many dramas. Even freshly sanded steel left in the rain for a day or two doesn't rust sufficiently to present too many difficulties and a simple swipe with a wire brush will clean it if need be. Moisture or oil trapped in joints will make you tear your hair out though.
    Going well Gazza.

  4. #64
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    i picked up a can of lanolin yesterday but Karl your giving me second thoughts on using it, what if theres 1-2 week old rust in the joint that cannot be wire brushed out?

  5. #65
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    OK gazza, I decided to try out an experiment today using your settings and see what happens. Before I start, this is using my machine and me as the welder so all comments reflect on me.

    This is 50mm x 50mm x 3.0mm. Here's how much I clean:



    This is the sort of angle I use for butts like this, about 80 degrees, 80 degrees:



    Here's a butt at 57A and a fillet at 65A, 1.6mm 2% lanthanated tungsten, 1.6mm ER70S-6 filler, 6L/m argon, #5 or #6 cup, gas saver lens:



    I did this fillet at 70A, the one that you said burnt holes for you:



    Here's the settings I'd personally start with, 100A butt, 125A fillet, 2.4mm 2% lanthanated, 2.4mm ER70S-6, 6L/m argon, #5 or #6 cup, gas saver lens:



    Here's both butts for comparison:



    Then I sectioned up the butts. 57A on the left, 100A on the right. I must say, I was unhappy with my 100A settings. Visually they looked great but you can see I only went about halfway down. It's a big gap and my torch angle might need to be more vertical and I might need to shove more filler down as I go and bump up to 110-120A. Any comments?:



    And here are the fillet cross sections, 65-70A on the top, 125A on the bottom. At first glance the lower amps looked OK in places but you can see that there is less penetration, particularly where I sectioned the beginning of the weld in the top left of the top photo. Worryingly, there is some evidence of incomplete penetration in the bottom left of the top photo too, but just along where the surfaces meet. There was actually OK penetration into each face:







    I also took up Karl's challenge to weld some dirty metal, from top to bottom:

    (very rusty 3.0mm plate)
    80A 1.6mm tungsten 1.6mm filler
    120A 1.6mm tungsten 1.6mm filler
    120A 2.4mm tungsten 2.4mm filler

    (medium rusty 2.1mm checker plate)
    80A 1.6mm tungsten 1.6mm filler
    100A 1.6mm tungsten 1.6mm filler
    100A 2.4mm tungsten 2.4mm filler

    (mill scale 2.1mm checker plate)
    old stick weld from a while ago
    80A 1.6mm tungsten 1.6mm filler
    100A 2.4mm tungsten 2.4mm filler

    OK I got the travel speeds very wrong in parts and the checker plate is tricky because sometimes it's 2.1mm and sometimes about 4-5mm where there's a checker. I obviously got some suck back and other things but I just wanted to see how it went on rust and mill scale. Pretty damn good as it turns out! Contamination didn't affect the arc. It might compromise the long term viability of the weld and the absolute strength for critical applications but effects were minimal at the time.




    In conclusion, for me 57A just didn't work at all for this material and the sections showed it. It didn't help that my hands were super, super, ridiculously shaky after lifting heavy stuff all morning. You can see I touched down twice with the butt. I had to weave all over the place with the low amps on the butt and the fillets and it just soaked heat and didn't burn in. For me, I wouldn't accept those for my projects.

    The higher amp stuff is more what I'd be happy with but you can see I'm still learning a lot and have a way to go. I would still accept that for my projects. I could probably bump it up 10A all round to get better results, so 110A butts and 135A fillets on 3.0mm material butt joins like that.

    Any criticism welcome!

  6. #66
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    Legion were u using the 100amps+ with the foot peddle? interesting and thanks for posting your results, ill do the same test tomorrow and cut vertically into my welds using my machines current setting that i was welding the trailer with

    do u think it would be a better idea if i ramp up the amps and use 2.4mm filler rods instead of 1.6mm filler rods?

  7. #67
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    Foot pedal, but I floor it until the end and only use it to taper off. I don't feather throughout very often.

    The filler for me depends on the amps. Some guys on US forums recently have been saying they mostly prefer 1.6mm filler and more frequent dabbing even on thicker material. For me, if the material is hot enough to melt 2.4mm filler then that's what I'll use. If it's not hot enough the 2.4mm will stick and it'll be frustrating.

  8. #68
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    Quote Originally Posted by gazza2009au View Post
    i picked up a can of lanolin yesterday but Karl your giving me second thoughts on using it, what if theres 1-2 week old rust in the joint that cannot be wire brushed out?
    Don't stress too much Gazza. The general thrust of what I am saying is that it is good that you are striving for a clean work piece, but that it doesn't need to be surgically clean and moisture (rain etc) or oil trapped in a joint will generally give you more issues than a bit of light surface rust.
    If it were me trying to tig weld a trailer outside, then I think I would invest in a cheapish tarp that I could put over the tacked up frame so as to keep off direct rain etc and thus avoid most of the issues. Not a big fan of spraying on oils etc unless I know I can properly clean them off before welding. On a side note, be very careful of using solvents such as petrol, thinners, turps etc on a tacked up frame to clean off oil etc. They can and will seep into the joint and potentially fill the hollow sections with volatile fumes that go BOOM once welding heat is applied.
    Above all else, don't stress too much, give it a go and if you strike a problem, step back and solve the problem.

  9. #69
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    thanks ill keep the lanolin for once all sides are welded or may even paint the joints at that time to stop rust forming, surprisingly my welds havent rusted yet not even a spec of rust on the un-welded sections maybe i didntflapdisc enough gal off? im not sure

    far too windy outside to do any welding today and i dont fancy welding the gal steel in the shed so im going to leave the weld and cut test for another day when the wind is calm

  10. #70
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    Quote Originally Posted by Legion View Post
    OK gazza, I decided to try out an experiment today using your settings and see what happens. Before I start, this is using my machine and me as the welder so all comments reflect on me.

    This is 50mm x 50mm x 3.0mm. Here's how much I clean:



    This is the sort of angle I use for butts like this, about 80 degrees, 80 degrees:



    Here's a butt at 57A and a fillet at 65A, 1.6mm 2% lanthanated tungsten, 1.6mm ER70S-6 filler, 6L/m argon, #5 or #6 cup, gas saver lens:



    I did this fillet at 70A, the one that you said burnt holes for you:



    Here's the settings I'd personally start with, 100A butt, 125A fillet, 2.4mm 2% lanthanated, 2.4mm ER70S-6, 6L/m argon, #5 or #6 cup, gas saver lens:



    Here's both butts for comparison:



    Then I sectioned up the butts. 57A on the left, 100A on the right. I must say, I was unhappy with my 100A settings. Visually they looked great but you can see I only went about halfway down. It's a big gap and my torch angle might need to be more vertical and I might need to shove more filler down as I go and bump up to 110-120A. Any comments?:



    And here are the fillet cross sections, 65-70A on the top, 125A on the bottom. At first glance the lower amps looked OK in places but you can see that there is less penetration, particularly where I sectioned the beginning of the weld in the top left of the top photo. Worryingly, there is some evidence of incomplete penetration in the bottom left of the top photo too, but just along where the surfaces meet. There was actually OK penetration into each face:







    I also took up Karl's challenge to weld some dirty metal, from top to bottom:

    (very rusty 3.0mm plate)
    80A 1.6mm tungsten 1.6mm filler
    120A 1.6mm tungsten 1.6mm filler
    120A 2.4mm tungsten 2.4mm filler

    (medium rusty 2.1mm checker plate)
    80A 1.6mm tungsten 1.6mm filler
    100A 1.6mm tungsten 1.6mm filler
    100A 2.4mm tungsten 2.4mm filler

    (mill scale 2.1mm checker plate)
    old stick weld from a while ago
    80A 1.6mm tungsten 1.6mm filler
    100A 2.4mm tungsten 2.4mm filler

    OK I got the travel speeds very wrong in parts and the checker plate is tricky because sometimes it's 2.1mm and sometimes about 4-5mm where there's a checker. I obviously got some suck back and other things but I just wanted to see how it went on rust and mill scale. Pretty damn good as it turns out! Contamination didn't affect the arc. It might compromise the long term viability of the weld and the absolute strength for critical applications but effects were minimal at the time.




    In conclusion, for me 57A just didn't work at all for this material and the sections showed it. It didn't help that my hands were super, super, ridiculously shaky after lifting heavy stuff all morning. You can see I touched down twice with the butt. I had to weave all over the place with the low amps on the butt and the fillets and it just soaked heat and didn't burn in. For me, I wouldn't accept those for my projects.

    The higher amp stuff is more what I'd be happy with but you can see I'm still learning a lot and have a way to go. I would still accept that for my projects. I could probably bump it up 10A all round to get better results, so 110A butts and 135A fillets on 3.0mm material butt joins like that.

    Any criticism welcome!
    That was a really good exercise and illustrates the need to run sufficient power in order to properly fuse the weld and penetrate.
    All in all, very valuable.

  11. #71
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    Hey Legion, great work with those tests and pics

    I went straight to the photos and looked at the low amp ones and thought that they looked like a dog's breakfast... but that was quickly explained - a good demonstration I think.

    The fact that the low amp fillets don't look too bad is probably due to your good technique - i.e. you've slowed down and being careful to still get the weld right into the corner.

    Your incomplete penetration on the higher amperage but welds reflects my earlier posts regarding sucking galvanising in from the back side. If you were fully penetrating, I think you would have more zinc issues. Despite not going all the way through, it would probably be hard to break them. The only reliable way I know of getting full penetration is looking for the keyholing as mentioned previously.

    I've noticed that my foot pedal affects maximum amps. So 100 amps without foot pedal connected is hotter than 100 amps with foot pedal flat out. Not sure why, and it might just be my machine, but something to keep in mind with comparisons. If you are doing really thick metal and the welder is maxed out then you might be better off disconnecting the foot pedal.

    My only other comments on the pics is that, I like to do a nice solid tack right on the corners, then make sure my welds fully marry in with the tacks. I recognise these are just scraps/demos, but thought it was worth a comment.

    Nice work with the pictures.

    - Mick

  12. #72
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    Thanks Mick.

    To get the low amp fillets looking ok I had to weave _a lot_. Same with the low butts. I had to hover in a spot to get it to melt and then little mini dabs with filler. Not how I like to work, especially with the shaky hands I had going on. I prefer almost ally speed, panic speed when you need to be on top of everything and a fumble means you're going to verge on disaster.

    I forgot to mention, although I'm sure you all know, my travel speed was a snails pace.

    My corners have always been weak. I position my head and hands and work for the majority of the weld and going around the corner at the end always fails me. But I was especially disappointed I didn't go one more forward movement and dab on my high amp vertical up fillet to tie it in to the butt.

    I suspect with my high amp butts I need to abandon the 80 degree angle thing. That's habit from what Grahame used to teach with thin section stick welding, where I'd point the stick at the corner to avoid blowing holes in the butt. I will modify my technique to point vertically down into the root but slightly bias to the corner.

    I might also start bevelling with 3.0mm material, not that I use anything that thick very often. Mostly it's 1.6mm - 2.0mm, 2.5mm is heavy structure for my little projects. So I doubt penetration is as critical for these projects. Still don't get galv issues from suck back.

    For reference the machine is a miller dynasty 200dx. Foot pedal by SSC.

    I like learning experiments like this, it was fun.

  13. #73
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    Quote Originally Posted by Legion View Post
    I suspect with my high amp butts I need to abandon the 80 degree angle thing. That's habit from what Grahame used to teach with thin section stick welding, where I'd point the stick at the corner to avoid blowing holes in the butt. I will modify my technique to point vertically down into the root but slightly bias to the corner
    Maybe, or maybe just make sure you are welding back from the top of the gap a bit more?

    Capture.JPG

  14. #74
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    i tryed this and it just blows holes in the thinner side like theirs no tomorrow

    Quote Originally Posted by WelderMick View Post
    Maybe, or maybe just make sure you are welding back from the top of the gap a bit more?

    Capture.JPG

  15. #75
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    I had a bit of spare time this afternoon so experimented a bit more to dial in the settings on this material.

    2.4mm 2% lanthanated
    2.4mm ER70S-6
    #5 or #6 cup
    ~6L/m argon
    50mm x 50mm x 3.0mm duragal, cleaned with flap disc only (external only, obviously)
    pedal floored, only using to taper
    fast travel, just the way I like it
    didn't wait between welds, so I was cheating a bit with some extra heat on top of my settings. Normally don't do that because of potential warpage but didn't care about that for this experiment.

    A 115A butt:



    The 115A butt and a 140A fillet:



    The (blurry) 140A fillet:



    The other butt, also at 115A, not much heat sink there:



    The other fillet, at 135A:



    The 135A fillet back up to the heat sink butt:



    Root penetration:



    Now I'm happy. I put a ~15 degree bevel on all faces, no (or almost no in places) land, couple of fit gaps where the continuous tube face wasn't square. You can see particularly on the butts root penetration is great. On the fillets it's just hitting the inside corner. I could maybe go up 5A there. On the inside of the tube there was just full penetration in a few places and it must have come close most of the rest of the way by the look.

    gazza, I've done this sort of thing before. It teaches me a lot. For a critical project like yours I'd suggest you've got nothing to lose doing something similar (except time). These settings that I'm happy with are over double what you said you're using, so it's a massive difference. I don't have a clamp meter to confirm the output amps but I'm very happy with my Miller and of all machines I reckon it would be as reliable as you can get (maybe some of the Euro brands would be similar and a couple of the old American brands).

    I don't know why yesterday I didn't straight up follow the 1A/thousandth rule that I normally go with. Obviously I was too conservative because I've been doing a lot of 1.6mm lately. As it turned out, the 1A/thousandth (or I usually go with 40A/millimetre, almost the same) was just about spot on with various compensations for open corners, fillets, etc.

    I didn't have time to chop it up but I reckon I'd be happy with those results too.

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