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  1. #1
    Join Date
    Jan 2013

    Default Looking for recommendation of copper free TIG filler for mild steel

    I am new to TIG welding, and just bought a Dynasty DX200 in the Spring, but haven't used it yet. I have done some reading, and decided that I want to use copper-free TIG rod for my mild steel welding projects. I'm not looking to start a debate over that or what the copper is used for, as I have read several past threads on that. I am willing to spend more money for better quality, copper free rod, although I don't need or want the NASA grade stuff!

    I would like some help with recommendations on manufacturer / supplier / type of copper free TIG rod for mild steel (used in 70's automotive body panels, and standard construction box tubing), because all of the local welding shops by me only carry the copper coated rod, and look at me strangely when I tell them I want copper free rod. So I am now looking online, but I have noticed it is extremely difficult to tell whether a rod is copper free or not by the information listed in many cases. The only exception being rod on Amazon by INETIG which specifically states it is copper free. Does anyone have any experience with this rod?

    Also, can anyone help point me to a source of information that would help me decipher the differences between filler rod like Welco 1200, and all the different variations of ER70SX where "X" is a number between 2 and 8? I see all of these rods advertised for sale, but am having trouble finding the exact differences, and a recommendation for which to use for what application or project. And I still can't tell whether they are copper coated or not.

    Thank you!

  2. #2
    Join Date
    Nov 2003


    Why are you so worried about the copper plating??

    it is just a flash coating intended to retard rust formation on the filler rods..

    most of which boils off during welding.. so is of no real consequence in the metalurgy of the weld bead...

    I TIG weld automotive sheetmetal all the time with ER70S6 filler... those welds are regularly worked and planished with no ill effect from any residual copper left over from the plating...

    As far as a cross reference or alloy composition listing...

    the Harris Alloy catalog is as good as any..

    it can be downloaded here..

    "Harris North American Alloys & Consumables"

    And if you want to decipher the AWS/ANSI designations of filler rod...

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  3. #3
    Join Date
    Sep 2009


    All I use is 70s2 or 70s6.
    The higher the s rating is, the more fluid (wet) the puddle is.
    70s2 has a faster freezing and more sluggish puddle. 70s6 has a more fluid puddle and wets out slightly more than 70s2.
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  4. #4
    Join Date
    Feb 2010


    Quote Originally Posted by snoeproe View Post
    All I use is 70s2 or 70s6.
    The higher the s rating is, the more fluid (wet) the puddle is.
    70s2 has a faster freezing and more sluggish puddle. 70s6 has a more fluid puddle and wets out slightly more than 70s2.
    It is true that the S6 wets better than the S2 or 3, but that is due to the amount of silicon and manganese used as deoxidizers. That is what the 2,3 and 6 designations are for.
    As for the bare tig rod, try some of your 1/16 or 3/32 E70XX SMAW rod with the flux knocked off. Clean it up with some scotchbrite and wipe it down with some acetone to clean it. Just a thought.

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  5. #5
    Join Date
    Dec 2005


    You have gotten good advise already, however I will add some points. Since you are new to the process I will assume you know diddly about it. Off the top of my head I can only think of one author that ever made a stink about copper coating on filler rods, and that was Richard Finch. Unfortunately what most people dont know is that he has a connection to manufacturer that makes the bare rods he talks about, so you can take his information on the subject and use it in place of your sears catalog. Anyway....the copper does no harm....zilch. It is gone long before the molten stage of steel, and no you do not get entrapped copper inclusions. Aerospace uses standard copper flashed fillers on parts much more critical than any car from the 1970's. Keep life simple and use industry proven standard materials. If you want to do something weird, just for the sake of being weird, then go for it, but do not confuse weird with "better".
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