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Welding rebar

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  • Welding rebar

    I'm still new to welding and I need some help. I'd like to weld some mild steel rebar together but I'm not sure which wire and liner to use. Can anyone advise me on which setting to use on my Shopmate 300 (wire speed and heat) and I'd like to use flux cored wire as I'm welding outside.
    The rebar is 1/4".



  • #2
    Rebar for what?

    If you are just using Rebar for "stuff" weld it up like Mild steel.

    Structural- I have no idea.


    • #3
      Yup, not sure what the settings for your machine are but its welded all the time for common stuff. Use common steel wire or electrodes.


      • #4

        If it will be subject to any stress at all, use 7018 or higher strength low hydrogen electrode, or for wire, Lincoln superarc la75 which is 8018 and you can use regular 75/25 mix gas to shield.

        I have experimented with rebar and was able to break the welds when they were standard wire (eros70) or mild steel electrode (6011). Moving up to Lo Hydrogen, not able to break.

        For what it is worth, that's my 2 cents.


        • #5
          Thanks Gentlemen. I'm not having much luck. I went to the local store (Canadian Tire) and bought some E71TGS 30mm flux wire. Same results. The welds are breaking when any kind of stress is put on them (the welds fracture in the weld itself. It seems tight on the metal). I'm welding the two pieces at 90 degrees angles, with a slight gap in between the pieces to get maximum penetration. The weld seems brittle for some reason so I'm not sure why. Again, I'm not an experienced welder so combos and setting are experimental for me. I'll keep trying.




          • #6
            I think I've got this figured out. As someone mentioned up the heat, up the wire speed. I did. I doubled the wire speed and set the heat on maximum. And I think the weld pool was contaminated because I was welding with the pieces laying flat on the floor. I think the iron has a bit of sulfur and other impurities and that was causing the porosity bubbles in the weld. I lifted the bar off the floor, got better ventilation around it and fixed the other and everything's working great again.

            Thanks for the input everyone.



            • #7
              Iron Head is right about the grades. Some are NOT weldable per the mfg. This only means you can't weld it to meet spec for the job intended. Some grades are weldable and are sold as such. Lower tinsel strength may weld better due to lower carbon level. Some rebar can actually make good tools, punches, etc. due to high carbon and other materials. Then lots is pure crap too.

              I just built a spiral 100' staircase out of #14 grade 70 rebar for a client. On some bends the bar would crack on the INSIDE of the bend. I could understand it cracking on the outside, but not the inside of the radius of the bend.


              • #8
                ALL of the grades of bar are weldable, some just more simple than others.

                Anyone interested should buy the AWS Structural Welding Code-Reinforcing Steel.



                • #9
                  Just to add a little. Rebar with a W is going to be your best bet for attempting to weld( W = weldable ). There is a wide range of tensile strength and carbon equivalents from one bar to the other. You will want to match your tensile strength of the bar to your wire and up the preheat to as much as 500 depending on carbon and dia.


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