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Mig cold joint??

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  • Mig cold joint??

    What does a mig "cold joint" look like?

  • #2
    Mig cold joint??

    Prob has snow or ice on it. ;-)

    Comment


    • #3
      [SUB[/SUB]

      For starters, look at the toes of the weld.

      Also, what type of joint in particular: lap, butt, etc?

      Comment


      • #4
        If I am correct, I think you are referring to "cold lap" or properly called incomplete fusion. It is a common problem in mig welding and can be on the underside of the weld or on the leg or toe of the weld. Obviously, if it is on the underside you can't see it. But if it is on the leg or toe, it will look like the weld is just laying on top of the base metal not really fused together. Kinda hard to visualize until you actually see it. Will try to find a picture and post it for you.
        It is usally caused by trying to weld too thick of base metal without some preheat or an incorrectly adjusted machine. It is also a very big problem when mig welding aluminum.

        Comment


        • #5
          Most of the joints would be fillets.

          I've taken mig courses and have been mig welding a long time but I'm not a "professional welder" in that I don't weld for a living. However, I weld a lot - way more than the average hobbyist and I get a lot of positive feedback on my skills. I manufacture a product which I sell mostly at car shows and swapmeets.

          Here's the dilemma ...
          On two occasions I've had people tell me "there are some cold joints there" but they've never actually pointed them out. The only thing I can see is that on some welds the surface of the bead is not "shiny". Otherwise, they all look pretty much the same to me. In 5 years of making this product I've had nothing but positive feedback from customers and not a single mention of a broken joint. And many of my products have been sold to fabricators who've felt building the product was not worth the effort versus buying mine!

          I will point out that I weld mostly 3/16 material but there are some lighter gauge pieces that I attach without changing the settings. But I can't see this causing cold joints.

          Could it be, as one observer pointed out when someone made the comment, that "some people just need something to complain about" ?
          Last edited by gkent; 02-05-2013, 02:26 PM.

          Comment


          • #6
            Well if you can use the same settings for 3/16ths on thinner material successfully, that makes me think it might not be hot enough for the 3/16ths.

            Post a pic
            Last edited by Cgotto6; 02-05-2013, 05:39 PM.

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            • #7
              gkent, Here is a good example I ran into on a combine bracket.
              Attached Files

              Comment


              • #8
                Mig cold joint??

                Could it be, as one observer pointed out when someone made the comment, that "some people just need something to complain about" ?
                U may hv hit the nail on the head ^ . And
                Jpence38 had pretty good explanation.
                But it pretty hard to get a cold weld on 3/16 metal with out it looking pretty bad.
                With that thin of metal if the weld looks good it's probably fine. Dull or shiny isn't a problem & the lighter metal at that setting should be a problem

                Comment


                • #9
                  Mig cold joint??

                  Dull or shiny isn't a problem & the lighter metal at that setting shouldn't be a problem.
                  Sorry mistyped:
                  Shouldn't !! Be a problem.

                  Comment


                  • #10
                    Originally posted by gnforge View Post
                    Dull or shiny isn't a problem & the lighter metal at that setting shouldn't be a problem.
                    Sorry mistyped:
                    Shouldn't !! Be a problem.
                    I guess maybe for tacking. But not for running a real bead.

                    Comment


                    • #11
                      When say "lighter", I'm only talking 1/8" material. I amusing the recommended settings for 3/16 material. Fwiw its a Miller 252.

                      Comment


                      • #12
                        Throw up some pics of the part and we can tell you exactly what's going on with the weld.

                        Comment


                        • #13
                          Originally posted by Cgotto6 View Post
                          I guess maybe for tacking. But not for running a real bead.
                          Why not ?? Different gauges of metal are joined together every day. Generally the higher setting of the two is used with most of the heat aimed towards the heavier gauge.

                          Comment


                          • #14
                            Mig cold joint??

                            Yep. I agree.

                            Comment


                            • #15
                              We really would have to see the weld joint(s) to really know what the complainers are referring too. Sometimes, you can have a weld with decent fusion but if the weld is really tall it is considered "cold" as well. Causes range from slow torch travel speed, wire feed too excessive, not enough power etc... Perhaps strive to make the weld no more than 1/16" thicker than the material depending on the type of joint. That may mean beveling out the joint or creating a "gap" depending on the thickness and if your welder is not able to make the weld in a single pass.

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