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stick welding with 7018

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  • stick welding with 7018

    I been practicing with 7018 rods lately and the first 1/4 inch of my weld has porosity in it. the rest of the weld looks great and I can beat on it with a 5 lb sledge hammer and not break it. I been using 1/8 inch mils steel with a 1/8 inch electrode on 100-120 amps. The electrodes most definatly have moisture in them as I have no oven Is it the rod or am I doing something I shoulodnt be doing? I drag the rod with no manipulation just a straight pull.
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  • #2
    The start porosity is from lack of shielding. It's pretty common, and why I cringe when people say to bust the flux off the end of a rod to make the restart easier, they are just about garanteeing porosity in the start. They may not see it on the surface but it'll many times be there.
    The proper thing to do, on a test or on any weld that will see UT or x-ray is to not restart any rod, throw it away and start every time with a new rod. That saves a lot of repair grief.
    But it happens even with a brand new rod if your not carefull because the 7018 flux doesn't go into full blown shielding mode until the rod has burned back into the flux a bit. That's why when you look at the end of a partially burned rod the flux forms a small cone that extends out a bit from the end of the wire. So with a brand new rod (or if you insist on restrarting used rods and if you do please don't bust the cone of flux off the end, just resart it with a light tap to distrupt the flux coating as little as posible) your best bet is to lite the rod and immediatly pull it back just a bit, for a second or so, letting a drop or two or three fall from the end. Then zoom in and commence to welding like a madman. That lets the flux cone form, and lets the wire heat up so that you're now making a weld that will (hopefully) shoot clean on x-ray.


    JTMcC.

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    • #3
      And use those start and stop tabs
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      • #4
        Yea, run off tabs give you a lot of leeway but on a pipe weld there is no such thing.


        JTMcC.

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        • #5
          Originally posted by JTMcCracken View Post
          but on a pipe weld there is no such thing.
          I’m sure it’s not the norm, because you would know . I do remember seeing it one time. It was at a General Electric nuclear test facility in San Jose CA. I can’t remember every detail because it was 1977. I know it was on a 2-G pipe repair, the guy used Tig. There was probably only about 15-pipe weldors on that project. They would weld all day; the x-ray crew would come in at night. Then on the whole there were only 2-guys who would do the repairs, if there were any. That was for C Norman Peterson, ever hear of them?
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          • #6
            Given the amount of slag with 7018 I'm thinking of using it for some gravel paths around my back yard..
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            • #7
              Originally posted by ZRX61 View Post
              Given the amount of slag with 7018 I'm thinking of using it for some gravel paths around my back yard..
              Ever run dual shield?

              I ran some 7/64th dual shield before, had to have a snow shovel to clean up
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              • #8
                You know, I've heard and seen starting tabs, but IMO they're not very field practical and I could honestly say that most of the time I don't think I could use them on a project even if I wanted to. Even in standard tests, it is common (at least around here) to have to do a restart in the middle region of the weld, often once on root and once on cap. I agree with the method early described by JT on puling back. After a box or two of rods it gets to be near-automatic.
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                • #9
                  Originally posted by Pile Buck View Post
                  And use those start and stop tabs
                  Pile, I don't know what "start and stop tabs" are.
                  Can you explain? TW

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                  • #10
                    Coalsmoke you’ve probally used them more than you realize. How many structural welding tests have you taken like this one pictured?

                    Tumbleweed, start and stop tabs are just any thin material use to start your weld, run into the permanent weld zone, then run up and out of the weld zone on a piece of material that can be broke off, and ground down.
                    Like JT stated, never reuse a rod, especially on a test, or code work. There is a reason they give you a test coupon like pictured.
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                    • #11
                      They are nothing more than small pieces of metal tacked on the edge of where the weld start and stops. You then start your weld on the tab and and end on the other tab. They are cut or ground off after welding. As JT said there is nowhere to use them on pipe.
                      Dennis


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                      • #12
                        Originally posted by Pile Buck View Post
                        Ever run dual shield?

                        I ran some 7/64th dual shield before, had to have a snow shovel to clean up
                        I also ran a lot of .120 NS3M, innershield. The flux was almost 1/4" thick after each pass! The snowshovel worked quite well.

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                        • #13
                          Originally posted by DetailerDave View Post
                          I also ran a lot of .120 NS3M, innershield. The flux was almost 1/4" thick after each pass! The snowshovel worked quite well.
                          I’ve never run any Innershield that big! That I can remember . I’ve seen Iron Workers run 3/32 NS-3M on pre-cast concrete deck panels. I’ve runs tons of 5/64-inch.

                          About 20-years ago I was in a fab shop in Spokane Washington, they had a lot of welding manipulators there. I didn’t actually measure the wire but it looked to be about 1/4-inch . The machines were not working either . I would have loved to seen them in action!
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                          • #14
                            Originally posted by Pile Buck View Post
                            That was for C Norman Peterson, ever hear of them?

                            I've heard the name but I don't know when or where.

                            JTMcC

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                            • #15
                              Originally posted by Pile Buck View Post
                              Coalsmoke you’ve probally used them more than you realize. How many structural welding tests have you taken like this one pictured?

                              Tumbleweed, start and stop tabs are just any thin material use to start your weld, run into the permanent weld zone, then run up and out of the weld zone on a piece of material that can be broke off, and ground down.
                              Like JT stated, never reuse a rod, especially on a test, or code work. There is a reason they give you a test coupon like pictured.
                              Nope, not in my limited lifetime Of course, I could just be the odd one out. The only tests I've done were for the structural company when I got into the ironwork gig. And, IMO it makes sense not to have the tabs. If you can't help but make a mess of the starts and need to use starting strips, then you won't be much good welding iron togther. No starting strips used there, none that I came across at least. Are they common place elsewhere in the welding field? I always thought they were primarily used to help a welder pass a test, and didn't think anyone would use them in the field. Do you guys have to do at least one restart in the middle of the test coupon as well for your general structural plate tests?
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