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  1. #1

    Default GTAW welding - puddle fizzes

    I'm TIG welding 4130 on a new roll cage. Every once and a while the weld pool will bubble and fizz and spew like a sparkler. Metal is ground clean and wiped with brake clean so I'm thinking its a gas coverage issue. I'm using a gas lense with 7/16" cup, 3/32" red tungsten, 13 cfm gas flow. Tried cranking the gas up to 16-17 cfm and didn't help. Can someone help me?

    Thanks,
    Craig

  2. #2
    Join Date
    Jan 2007
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    hillsboro,OR
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    45

    Default

    Are you drilling a hole close to the weld so the hot gas in the tube from the weld can vent if not it is venting through your weld and pushing up your weld. make sure you have 1\8" to 1/4" hole drilled close to the weld area to vent.
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  3. #3
    Join Date
    Oct 2006
    Location
    Mpls, MN
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    Default

    You don't need the hole close to the weld. You just need to make sure the joint doesn't create a sealed chamber. The hot air getting out farther away from the joint would probably be preferable.

    1/64" hole would be sufficient. For practicality sake, you'd make it bigger just to not break bits.

    After the weldment cools, you can then go back and fill your breather hole.
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  4. #4

    Default

    Typically I do use a hole at the tube intersections to allow the heated gas to vent out of the tube I'm working on. I have had the puddle blow out on me a time or two where I didn't drill holes and got to the end of the weld. This wasn't one of those cases though, I was actually welding up a vent hole on a piece of tubing about 4' long. The tubing was all cool and the instant the arc started it started to fizz and piss like crazy. Couldn't have been any gas pressure in the tubing that quick....something else was going on. It acted similar to when I use a standard 3/8" cup without a gas lense and have too much stick out (ie. poor gas coverage).

    Craig

  5. #5
    Join Date
    Oct 2006
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    Mpls, MN
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    Default

    Any chance of contamination in the area?
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  6. #6
    Join Date
    Mar 2006
    Location
    Queens NY
    Posts
    1,547

    Default

    In practcing my 4130 tube welds i saw this problem too. I had switched to a #8 cup on my gas lense from a #6 just to see if it helped any, i increased gas flow but it didn't help much. Returning to the #6 solved the problem. I'm guessing there is a relationship between the diameter of the tubing and the size of the cup. Maybe too big of a cup lets the gas flow around the tube and pull in air. At least thats what i think happened.

  7. #7
    Join Date
    Oct 2006
    Posts
    694

    Default

    You're wasting your time with the brake cleaner. It's not necessary to wipe down with anything after grinding to bare metal. You're only taking the risk of contaminating your weld with your cleaner.

  8. #8
    Join Date
    Oct 2006
    Location
    Rootstown, OH
    Posts
    90

    Default

    Where are you getting your filler from? I got some bad filler from the LWS when I was in a bind that did this. Changed to a more reputable (non Chinese) brand and the problem went away. Fortunately I was welding non-critical stuff when this happened.

    Are you deburring the inside of the tube? If you have to grind to fit and don't clean the slag out of the inside of the tube, you can have this problem too. I have gotten into the habit of running a deburring tool around the inside of tubes before welding.
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  9. #9

    Default

    I always deburr and degrease the inside ends of the tubes as well.

    Maybe it is due to contamination, it's just odd. Just about done with the chassis now anyway, only a few little spots to finish welding up.

    Craig

  10. #10
    Join Date
    Jun 2007
    Posts
    482

    Default

    Quote Originally Posted by PontiacRacer View Post
    This wasn't one of those cases though, I was actually welding up a vent hole on a piece of tubing about 4' long. The tubing was all cool and the instant the arc started it started to fizz and piss like crazy.
    Craig
    There's your problem. Welding up a vent hole is tricky. If you try and hold your arc over the vent hole atmosphere will meet arc. Gas cannot flow through the hole into the tube because it is filled with air and that air has nowhere to go. This collision is going to stir atmosphere from in the tube into your arc/pool, etc. Normal and expected occurrence if you try and start a puddle right over the hole.

    Any other times?

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