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Aluminum tig joint problem.

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  • Aluminum tig joint problem.

    I am trying to tig two flat pieces of .125" aluminum together with a tight butt seam. When the puddle starts each piece melts and pull away from the other
    creating a void. It's like they're repelling each other. The only way to stop it from continuing is to get some filler to bridge the gap and go on. I've seen welds without filler before. Is it normal for the edges to do this? I don't see this as being any different than doing spot welds that do the same for me.
    The pieces are flat on a table when welding.
    Nick

  • #2
    When i have had that problem its because of lack of cleaning and fitup. The faces of the butt don't get a lot of arc cleaning, when the metal melts the surface tension causes metal to start to round, since there is probably oxide between them if they are barely touching they wont come together. I clean well and start with low power to get more cleaning while heating up, if you can keep the coupons pushing against each other it helps too. Or you can just add filler.

    Comment


    • #3
      tig aluminum

      i dont think you can fuse weld aluminum,but i am not positive.i have always used filler rod.

      Comment


      • #4
        Sure you can. I do it tacking all the time.

        Comment


        • #5
          Usually tigging Aluminum requires filler rod. If you want to fuse up with only base, bend up a flange on either side of the joint the thickness of the material (i.e. .125 flange for .125 Al). Heat with your tig torch and the flanges will melt filling the gap.

          John

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          • #6
            Originally posted by monte55 View Post
            I am trying to tig two flat pieces of .125" aluminum together with a tight butt seam. When the puddle starts each piece melts and pull away from the other
            creating a void. It's like they're repelling each other. The only way to stop it from continuing is to get some filler to bridge the gap and go on. I've seen welds without filler before. Is it normal for the edges to do this? I don't see this as being any different than doing spot welds that do the same for me.
            The pieces are flat on a table when welding.
            Nick
            The answer to this question depends more on the type of joint. An outside corner would be better to learn for tacking without filler. To do your butt weld, clamping somehow would be more likely than not also.
            Aluminum expands greatly also, so if you are using "strips" then you'd
            need to get the first couple of tacks done and get the two parts shrinking from previous tacks as you move on. You can see it grow apart and shrink together as you go. Shrinking and growing is something you learn to count on with aluminum...it is much more pronounced than steel IMO
            There are some things you just have to struggle with untill you get good.
            I don't tack much without filler even tho I have worked in factories that we did it a lot...I simply do not like the results myself. They crack easy. YMMV

            Comment


            • #7
              Yeah we tack aluminum all day long without filler BUT only on outside corners.
              FuisionKing is right, tacks without filler do crack easily so it really depends what your doing and the shrinkage can be a big issue with aluminum welding. We've had parts 8ft long shrink almost an 1/8" Not good if you haven't planned for it.

              Comment


              • #8
                while you can get aluminum to fuse without filler if everything is perfectly clean and the fit up is perfect, it is much easier with filler. so i think the best advice is to just use filler-- the weld will be easier to make and stronger as well.

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                • #9
                  The material must be FRESHLY cleaned, and I agree, use filler.


                  HEY! My first post! Hi kids!!!!!CHEERS!

                  Comment


                  • #10
                    Originally posted by shoprat View Post
                    i dont think you can fuse weld aluminum,but i am not positive.i have always used filler rod.
                    Sure you can! It is a very common process when tacking up parts.

                    Griff

                    Comment


                    • #11
                      Wondering, if a copper backing plate would help dissipate some of the heat to slow the melt down a bit?

                      Comment


                      • #12
                        Originally posted by monte55 View Post
                        I've seen welds without filler before.
                        Nick
                        Nick,

                        Are you wanting the entire weld bead to be without filler?

                        Comment


                        • #13
                          Originally posted by Broccoli1 View Post
                          Nick,

                          Are you wanting the entire weld bead to be without filler?
                          Not really. But the way it's going I couldn't even make tacks. The joint was a
                          6" x .125 round disk set inside a 6" ID tube set flush with the end and a very tight seam. When I heated the joint and as it started to puddle, the edges of each piece melted back away from the seam line leaving a void. If I applied a little filler to bring the two molten edges together, then I could continue without filler if I was careful but the weld was flat and no real strength. So......how does one make a tack weld when this happens?
                          Nick

                          Comment


                          • #14
                            Originally posted by monte55 View Post
                            Not really. But the way it's going I couldn't even make tacks. The joint was a
                            6" x .125 round disk set inside a 6" ID tube set flush with the end and a very tight seam. When I heated the joint and as it started to puddle, the edges of each piece melted back away from the seam line leaving a void. If I applied a little filler to bring the two molten edges together, then I could continue without filler if I was careful but the weld was flat and no real strength. So......how does one make a tack weld when this happens?
                            Nick
                            You must make these tacks fast to keep the edges from rolling back. With the disk set flush and with a very tight seam that tack should be very easy to do if you have enough machine to "get there right now". If you have to build heat with time IT WILL NOT WORK.

                            HTH
                            Griff

                            Comment


                            • #15
                              Originally posted by griff01 View Post
                              You must make these tacks fast to keep the edges from rolling back. With the disk set flush and with a very tight seam that tack should be very easy to do if you have enough machine to "get there right now". If you have to build heat with time IT WILL NOT WORK.

                              HTH
                              Griff
                              X2

                              I was going to interject something about getting it done quickly. Don't dilly-dally, get some heat in there, and fast.

                              On stuff that's really important, I'll test a few things on scrap first to get my head in the game.

                              Comment

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