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  • gas lens destruction

    I'm having issues with the arc jumping back up into the cup and melting the screens in the gas lens. I'm thinking that the tungstens (re-ground) that I was using were not "broken back" far enough and caused the arc to wander. Or, possibly a poorly seated collet,(although it was as tight as I could make it)? It happened with lens from multiple sources. Any thoughts on this? I was welding .120, 304 w/1/16" ceriated, 90amp, 100%argon for what it may matter. It occurs upon initiation of the arc.
    Thanks
    Last edited by jrhesch; 08-24-2011, 10:35 AM.

  • #2
    Could be your tungsten is on the small side.

    I prefer 3/32 tungsten on 1/8" SS.
    Nothing welded, Nothing gained

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    • #3
      Try cleaning your chuck. Sometimes, tungsten ID paint chips off the back and prevents good contact with the tungsten, acting like a capacitor which can cause arc jump from a gas lens.

      If you remove tungsten from the back side, chipping of the ID paint ( orange in your case) is prevented. But if you change tungsten from the front, paint can chip off and lodge in the chuck.

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      • #4
        You might try changing the cup, if it is contaminated this will happen sometimes.
        just a thought........

        I reread your first post, 90 amps may be a bit much for 1/16 tungsten, I would prefer 3/32 for 90 amps.
        Last edited by popspipes; 08-25-2011, 07:23 PM.
        mike sr

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        • #5
          I did a t weld on some cold rolled once that was clean but what ever was in the material make up was junk and the material itself would actually pop or miniature explosion and pieces of molten metal wuold contaminate the tungsten and screw up my gas lense. I new it was a material issue because I took some scrap same thickness different supplier and no problems.

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          • #6
            Originally posted by pro mod steve View Post
            I did a t weld on some cold rolled once that was clean but what ever was in the material make up was junk and the material itself would actually pop or miniature explosion and pieces of molten metal wuold contaminate the tungsten and screw up my gas lense. I new it was a material issue because I took some scrap same thickness different supplier and no problems.
            Rimmed or capped steel. This is steel that was not treated with silicon, aluminum or manganese so it still has oxygen and carbon monoxide dissolved in the steel. As it solidifies, these gases come out of solution and form pockets. Relatively pure steel with very low carbon can be cut from sections of the cooling ingot, these steels are easily cold rolled into thin sections, substantially flattening the gas pockets, until you melt them in welding. Heat+trapped gas goes POP! Fortunately, most domestic steel is killed as are the raw products you buy. Reusing mystery metal is always suspect.

            Weldable steel is killed. All stainless is killed since any oxygen would "sugar" the chromium, effectively wasting it. Chrome and other metals are added after primary steel refinement (basic oxygen steel, electric arc furnace or vacuum arc remelt).

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            • #7
              Thanks

              Thanks for the replies-the ID paint on the inside of the collet sounds like a good possibility. I've noticed some of the marking paint gone from the ends. I don't think the metal was an issue as the "incident" was happening up inside the cup and the metal was fresh and new. The cup was an 8 and looks relatively clean-just a light gray inside with no debris. Max amps were 90 but the problem happens upon initiation when I first crack the pedal(5-10a) and if I continued and went to full throttle the wander was overcome but by then the damage was done. I was bar-tacking a 1/16 panel to a frame of 1/8 so I would imagine I was using about 60-80a. I've experienced no problem running as much as 110 through 1/16 tungsten in a "standard" collet and cup-just when using the gas lens. Perhaps I'll try removing the marking paint next time and see if it still happens...

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              • #8
                Originally posted by popspipes View Post

                I reread your first post, 90 amps may be a bit much for 1/16 tungsten, I would prefer 3/32 for 90 amps.
                1/16 ceriated will take 150 Amps.
                http://www.millerwelds.com/resources...ints_tips.html

                The smaller tungsten will (could) start better but it will also wear faster.
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                • #9
                  I have had this same problem at times, I am thinking it may have been the tungsten, if possible try a stick from another box, also the gray color inside the cup may be what the arc is tracking on.

                  I use gas lens exclusively for the last several years and this is unusual, most of my work is low current these days though.

                  try a new tungsten from another box.
                  I would replace the cup if its not the original color as it may be contaminated.
                  Make sure the work is grounded well, not arcing at the ground connection to the work, I had this happen on aluminum a few years back, it was dealing me a fit till I found it.
                  It could also be caused by the material gassing off as well, if the cup is gray in color on the inside something is causing that.

                  I used the 3/32 on the job because it was more durable mechanically than the 1/16 at least that was my prefference.....

                  Keep us posted on what you find, I am curious as to what is causing it......
                  Last edited by popspipes; 08-26-2011, 05:17 PM. Reason: more info
                  mike sr

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                  • #10
                    I keep cups clean with a small round diamond file. Cracks can be seen easier when clean, such cracks can serve as arc paths since they trap metal vapors and dirt.

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                    • #11
                      Originally posted by Keith_J View Post
                      I keep cups clean with a small round diamond file. Cracks can be seen easier when clean, such cracks can serve as arc paths since they trap metal vapors and dirt.
                      The cups will clean up like new if you have a bead blaster.
                      Richard
                      West coast of Florida

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