Tig welding aluminium.

Discussion in 'Shop Talk' started by MelissaW, Apr 22, 2006.

  1. MelissaW

    MelissaW Well-Known Member

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    Hi all! My husband has a question about tig welding aluminium. Here it is:

    We have a brand new lincoln electric 185 tig welder at work. I need to weld 1/16 inch aluminium boxes together. I can do the butt joints, but I'm having trouble with the inside corners, and I have to do it from the inside, not the outside. Do you have any suggestions? I've tried different settings, and still I can't get the weld to pool on both sides evenly. What setting should I start with? I'm using the 1/16 inch tungston rod, a 15 gas flow, and the machine has a thing where you can either go from automatic cleaning to welding. So far I've found that it's a little easier to leave it on more cleaning and less penetrating. I've tried it anywhere from 50 amps to 80 amps, and I just need suggestions on where to start. Thanks!
     
  2. moopups

    moopups In Remembrance

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    Are you useing Stargon shield gas or an other type of gas? Is there any air flow that would disrupt the gas's presence? Are the parent metals clean?
     

  3. Ross

    Ross Moderator Staff Member Supporter

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    No filler rod?
     
  4. MelissaW

    MelissaW Well-Known Member

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    I'm using 100% argon at 15. The parent metal is brand new, mill finished .050. I'm cleaning it with a stainless steel brush, and I've also tried it an aluminium cleaner that we got from AGA. I've tried it with, without, and in both combos. I've tried 1/8 inch, 3/33, and 1/16 inch filler rod. I can get a big blob, but I can't get it to flow nice and make "fish scales".
     
  5. ace admirer

    ace admirer Well-Known Member Supporter

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    Well its a tough job anyway..why does it need to be done from the inside? is the problem heat penetration into the fillet of the corner? would a much smaller nozzle help you get into the fillet? have you tried a little preheat from the outside corner maybe with a ox/acc torch? the inside corner is hard to pump heat into..its gets wicked away until the weldment (box) heats up enough to start cooking your glove

    not to insult you but....is the blob shiney or black or gray oxidized?
    is your electrode rounded and clean?
    is machine set for continuous frequency?

    the blob sounds like no puddle formation...lack of heat at the fillet

    and above all remember...its a tough job....practice means failures.
     
  6. MelissaW

    MelissaW Well-Known Member

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    Thanks Ace! I'll try a smaller cup. Any suggestion about how far the electrode should stick out of the cup? Thanks a lot for the tips!
     
  7. longrider

    longrider Southern Gent

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    Hi folks, the tig book from lincoln states that for 1/16" material you would use a 1/16" Thoriated Tungsten rod with a sharp tip and a stick-out of 1/2". 1/16" Filler rod. At 60-80 amps. 15 volts. travel speed is 10ipm. Cup Diameter is 3/8. and Argon Gas flow at 20cfh.

    You might consider your options as to polarity: DCEN will give you more penetration with no cleaning (electrode last longer). DCEP will give you a shallow penentration With rod cleaning. AC runs with a balance cleaning half of the time and working half of the cycle.

    this from table 6 page 33 of the GTAW handbook from Lincoln Electric.(JFLF-834) $9.95 ISBN-0937390003

    i was smart in one respect, i bought every book and pamphlet while i was at their welding school two years ago, yet i still cant tig copper for $#!+. but i've got the books to tell me what it should look like.

    I will say that it looks like your gas flow is a bit low-and that will make a difference especially in odd angles. And the 185 has to be tweeked to just the right amperage or your gonna be frustrated. your going to have to play with it to dial it in just right.
     
  8. ace admirer

    ace admirer Well-Known Member Supporter

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  9. longrider

    longrider Southern Gent

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    depends on your polarity. DCEP is a sharp tip. DCEN is blunt. AC is rounded. My reference is JFLF-834. and yes, each metal is different in this regard.
     
  10. flaswampratt

    flaswampratt Well-Known Member

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    Smaller cup and extend the Tungsten a little further out.

    HTH & YMMV.

    Best Regards......

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