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Correct pattern for welding tubing?

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  • Correct pattern for welding tubing?

    Hey guys. Ive been struggling to get a good weld on tubing and have come here for help. I feel Im pretty proficient with straight welds such as welding box tubing or plate but when it comes to welding tube I end up with sub par results.

    I tend to use a zig zag or crecent type pattern but when I do it on a tube or round joint it ends up horrible. Ive come to the conclusion that what works for straight joints isnt neccessarily good for a fishmouth or any type of round filet.

    So my question is, What is a good pattern to use? Ive even considered just hitting the joint with a straight bead but when I do it tends to get a bit cattapillar like which Im not ok with either. Im want to be able to lay down a nice flat bead that is structurally sound, Ive got that down for the straight now I need it for tube.

    HELP!!

  • #2
    What weld process? For MIG or STICK I use small circles. TIG, it's pretty much dip and go.

    Comment


    • #3
      Using a Millermatic 180 with 75/25 gas.

      I seems when I weave the weld is huge compared to a straight weld I can do. Ive tried to do a straight no weave pattern and the weld is more confined but it sits proud which I know is wrong.

      For some reason I cant seem to get welding a tube down . I am self taught so I dont really have anyone to ask other than asking questions on forums or watching videos. I even watched Covells video and I didnt seem to gain anything.

      I really hoping theres a resource for me to go after to figure out how to correctly weld tube.

      Comment


      • #4
        OK so your using MIG. but you left out size of pipe and hard wire or flux?

        if it's small pipe 2" and under it's all in your angle of the gun (15degree and pushing).
        let's say your doing a pipe rail on a bench T joint. just start at the top center and weld down hand left then right from the top.
        if it's a pipe over 2" then same for root and same for cover but with a weave (moving fast side to side)
        if it is going to be a structural weld then you should be sticking it anyway.

        Comment


        • #5
          i only had some pipe pic's that i sticked. if you need i'll weld some pipe with my 211.
          Attached Files

          Comment


          • #6
            Originally posted by vin-man welding View Post
            i only had some pipe pic's that i sticked. if you need i'll weld some pipe with my 211.

            I'd be interested in seeing < 2" MIG action

            Comment


            • #7
              Im welding 1 1/2-1 3/4" .125 mild steel DOM. Im using solid core .030 wire with 75/25 gas. This is for automotive apps such as trans crossmembers, engine mounts, bracing ect.

              Stick welds arent legal for use.

              Ill give a try pushing instead of dragging like I tend to do with flat stock. Heres a question regarding that, will pushing require any different settings as opposed to dragging? My thinking is that since Im moving into cool metal I may need to either slow down or up the voltage to keep the heat up.

              Ive never really practiced with a push technique because my welds came out good with the opposite so I never tried. Guess Ill try it tomorrow.

              Comment


              • #8
                You've been dragging? That's your problem right there. Also not a good technique for gas shielding coverage either.

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                • #9
                  I havent experienced any issues with my straight welds dragging the gun. I know what a weld looks like when it is exposed to air and they arent even close to that.

                  Comment


                  • #10
                    Originally posted by CalRewireMatt View Post
                    I havent experienced any issues with my straight welds dragging the gun. I know what a weld looks like when it is exposed to air and they arent even close to that.
                    Before you dismiss the advice of pushing the gun in this application and continue with your old technique, bear this in mind: Insanity is when you repeat the same thing over and over expecting different results.

                    You are experiencing issues with dragging the gun on tubing. Sheet is more forgiving.

                    You're not going to see porosity and lack of root fusion because it's going to be under all that pretty MIG weld bead.That's the downfall of MIG. Anyone can make great looking welds, even if they are not sound.

                    The gun needs to be tilted in the direction of travel so the shielding gas can get down in the gap between tubes and cover the root before your heat gets there. It doesn't do as much good if the shielding gas gets there after it's molten. It also directs the heat of your arc toward the root instead of the weld pool.

                    The greater the drag angle, the more convex the bead. The greater the push angle, the more concave the bead. At a push angle of about 15 degrees is where you get flat welds.

                    Comment


                    • #11
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                      Comment


                      • #12
                        Well said Bodybagger,

                        I have read alot and watched alot and then read even more. I only wish I had read a post like yours when I was first starting Mig. In a few short lines you made it easy to understand and why it is like it is.

                        Comment


                        • #13
                          Im not dismissing anything!! Believe me if I ask for advise Im going to take it.

                          As far as my drag goes theres no undercut of the bead and full penetration is there. I do the typical destructive test with a hammer and a vice and the metal failed before the weld . With that said Im not anywhere pro so please dont construe what I said in my past post as some kind of snotty remark.

                          As far as gun angle is concerned I think Im keeping a 15 deg angle or so. I keep the gun just back enough to see the pool.

                          As said Im going to practice doing a push and see how things go.

                          Believe me I appreciate any help I can get.

                          Comment


                          • #14
                            Well this morning I made up some sample joints and tried out pushing the weld.

                            All I have to say is WOW!! I could never figure out what was wrong with what I was doing and I found it. The welds are nice and even without the heavy lumps I had before. It took me 2 times before I got the technique down and every one after was great.

                            Other guys in the shop said theyd trust themselves in a car with welds like I did.

                            All I can say is thank you very much for the recommendation as it opened me up to being able to build much more than I could before. I would only use square stock because of my horrible technique with tubing but now I wont be scared at all to use it whenever possible.

                            Thanks again.

                            Comment


                            • #15
                              I'm in the process of building a chassis with a lot of tubing in it. The tubing is about the same size as you are inquiring about. I TIG welded it all for the very reasons people have mentioned (quality of penetration and being able to better see what I was doing). HOWEVER, it took a very long time. Also, I was watching the 24/7 on HBO that showed them building the NASCAR chassis. I saw they seemed to be MIG welding everything. Next time I build a chassis I would love to MIG in an effort to move a little faster. I'm only a hobbiest, but it sometimes gets hard to stay motivated when you have hours and hours of just welding after everything is tacked up.

                              I'd love to see some video of someone welding. I can read all I want to, but I find (especially in welding type applications) seeing someone do it correctly is of much more benefit.

                              Thanks
                              JP

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