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  • "coupons"

    How did the word, "coupon," come to be used to refer to, as I understand it, small pieces of metal to develop welding proficiency?
    Just got curious.

    Now, a "real" question. In tig welding 1/4" coupons I made for myself I decided to use 3/32" tungsten. It came out looking pretty good. I whaled on the two welded pieces (lap joint) with a BFH and the weld held. Am I pushing the ability of that size tungsten or is it generally o.k.? I don't see myself welding metal that thick very often, if ever, being a hobby welder and 4x4 project kind of guy though.

    Kind regards,

    Vic

    p.s. I DID search for answers to both questions and didn't make much progress. So, . . ..

  • #2
    Tungsten size depends on the tungsten type, polarity (usually DCEN for steels) and current you are running, not the material (though the material thickness does relate to the current)

    See: http://www.millerwelds.com/resources/TIGhandbook/

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    • #3
      the 3/32" tungsten will be fine depending on the type and the angel of grind. as the amps go up you can fatten the grind a bit and add a slightly larger blunt on the tip.
      what welder, amps, and tungsten type are you using
      i use 2% lanthenated on every thing.
      you can get by easily with only 3/32” diameter tungsten. Diamond ground can send you some samples with a 20 degree taper and a .020” flat. This should do everything from 30 amps up to 120 amps and maybe higher. For the 120 amps to max on the Dynasty 200DX the same 3/32” tungsten will work. Use a 35 degree taper and a .030” flat. This thicker taper and wider flat will handle the current better. The 1/16” will only help your arc stability “somewhat” in the 10-25 amp range.
      thanks for the help
      ......or..........
      hope i helped
      sigpic
      feel free to shoot me an e-mail direct i have time to chat. [email protected]
      summer is here, plant a tree. if you don't have space or time to plant one sponsor some one else to plant one for you. a tree is an investment in our planet, help it out.
      JAMES

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      • #4
        Thanks for the link. I had found this resource a couple years back and had forgotten about it.
        The chart says 1/8" tungsten to weld 1/4" mild steel. So my question is, can 1/4" mild steel safely be welded using a 3/32" tungsten in a single pass? Thanks for the help. Vic

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        • #5
          Originally posted by El Cazador View Post
          The chart says 1/8" tungsten to weld 1/4" mild steel. So my question is, can 1/4" mild steel safely be welded using a 3/32" tungsten in a single pass? Thanks for the help. Vic
          For you're purposes yes. The problem with using too small of a tungsten is that it gets too hot and breaks down quick and you can contaminate the weld and it might not be X-Ray quality.
          To all who contribute to this board.
          My sincere thanks , Pete.

          Pureox OA
          Westinghouse 300 amp AC stick
          Miller Syncrowave 250
          Hexacon 250 watt solder iron

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          • #6
            Originally posted by El Cazador View Post
            How did the word, "coupon," come to be used to refer to, as I understand it, small pieces of metal to develop welding proficiency?
            Just got curious.

            It comes from the Latin word colaphus, which means "a blow with the fist."
            In Old French, a language that developed from Latin, the Late Latin word colpus, derived from colaphus, became colp, or modern French coup, with the same sense. Coup has developed in French, gaining numerous senses, participating in numerous phrases, such as coup d'état, and giving rise to many derivatives, including couper, "to divide with a blow, to cut." Couper yielded the word coupon, "a portion that is cut off,"
            So, welding coupons are a portion cut off from the same metal you are practicing to weld or being tested for proficiency on.

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            • #7
              Thanks a lot PUMPKINHEAD, I love etymology. I get Merriam-Webster's "word of the day," and the history of the words is always more interesting than the meaning of the word itself.

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              • #8
                I'm impressed PUMPKINHEAD, no sarcasm intended. That is a pretty interesting little essay.
                To all who contribute to this board.
                My sincere thanks , Pete.

                Pureox OA
                Westinghouse 300 amp AC stick
                Miller Syncrowave 250
                Hexacon 250 watt solder iron

                Comment

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