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  • Undercutting

    I tried to do a search on this but my internet kept saying it couldn't display the page for some reason. Anyway, I use MIG 99% of the time but I practice my stick rod welding anytime I get a free minute. I keep having a problem undercutting when welding a horizontal piece to 90 degree vertical piece. The bead starts good, but as I go further I start undercutting the vertical piece. Oh, I'm using a 7018 3/32 at about 90 amps. I try to direct most of the heat to the horizontal piece but still get the undercutting. Thanks.
    At work:

    Millermatic 251
    Miller Bobcat 250
    Miller Thunderbolt XL
    Hypertherm Plasma Cutter

    Oxy-Acy Torch
    Dewalt Grinders
    Milwaukee Porta-band
    Delta Floor Drill Press
    Delta Bench Grinder and Belt/Disc Sander
    Ellis Industrial Bandsaw

    At Home:

    Millermatic 180

  • #2
    I think you're talking about a horizontal fillet...hesitate on the vertical piece just a tad to prevent undercut, and slow your travel a bit, too.
    Arcin' and sparkin', Rocky D <><
    Experience is something you don't get until just after you need it.
    IF YOU CAN READ THIS, THANK A TEACHER...
    IF YOU'RE READING THIS IN ENGLISH, THANK A SOLDIER!

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    • #3
      As you drag puddle along on weave it takes a little time for puddle to catch up at side and fill in under cut. You can see this if your looking for it. Becomes a zen rhythm thing that feels right with practice.

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      • #4
        3/32 rod at 90a has a lot of arc force so either reduce the amperage or go to 1/8". the proper rod angle has more to do with it though

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        • #5
          Thanks, I'll give these suggestions a try.
          At work:

          Millermatic 251
          Miller Bobcat 250
          Miller Thunderbolt XL
          Hypertherm Plasma Cutter

          Oxy-Acy Torch
          Dewalt Grinders
          Milwaukee Porta-band
          Delta Floor Drill Press
          Delta Bench Grinder and Belt/Disc Sander
          Ellis Industrial Bandsaw

          At Home:

          Millermatic 180

          Comment


          • #6
            It ain't very straight but about 85A and simply dragging the rod along at the right speed.
            http://www.facebook.com/cary.urka.urkafarms

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            • #7
              Originally posted by cajun1 View Post
              I try to direct most of the heat to the horizontal piece but still get the undercutting. Thanks.
              The more you "try to direct your heat away" from the undercutting, the more undercutting you will get.
              *** Disclaimer ***

              As I have no wish to toy with anybody's life, I suggest you take this and all other posts with a certain amount of skepticism. Carefully evaluate, and if necessary, research on your own any suggestions or advice you might pick up here, especially those from my posts, as I obviously haven't the skill and experience exhibited by some of the more illustrious and more successful members of this forum. I'm not responsible for anything I say, as I drank toxic water when young.

              Comment


              • #8
                Originally posted by calweld View Post
                The more you "try to direct your heat away" from the undercutting, the more undercutting you will get.
                Good catch---

                As 5quarter and calweld are saying, rod angle means a lot...

                Think of it as a straw, shooting your fill metal where you want it...it IS a zen thing(thanks Roger)....

                If you get undercut on the left,lay the stinger more horizontal, shooting to the left, and slow down a taste, it'll fill---

                When I stick weld with 7018, that rod/stinger combo is never in the same position for more than seconds...I am watching the puddle, reacting to it automatically....watch your puddle, watch that it doesnt get too long, too short, go to the left or right, make a perfect puddle, life is good---

                Comment


                • #9
                  The one I post was overhead fillet, I just never move anything but in a straight line, simple drag. (well sort of straight) hahaha But no other motions, just let it fill. And it is a thing, I tried to get one to undercut bad but just cant seem to do it. This is about my favorite lo-hi weld, I like it better than flat. Its just so neat when you can get the bead to flatten out, no droop.
                  http://www.facebook.com/cary.urka.urkafarms

                  Comment


                  • #10
                    Originally posted by TEK View Post
                    Good catch---

                    As 5quarter and calweld are saying, rod angle means a lot...

                    Think of it as a straw, shooting your fill metal where you want it...it IS a zen thing
                    (thanks Roger)....


                    If you get undercut on the left,lay the stinger more horizontal, shooting to the left, and slow down a taste, it'll fill---

                    When I stick weld with 7018, that rod/stinger combo is never in the same position for more than seconds...I am watching the puddle, reacting to it automatically....watch your puddle, watch that it doesnt get too long, too short, go to the left or right, make a perfect puddle, life is good---
                    Sure NuFF.
                    I'm not sure what Zen should mean, but in metal-working
                    if one has any buisness doing it at all, and sticks with it.........
                    Something happens, and you find a junction of man / motion & metal.
                    Tig filler adding, is another. (At least for me).
                    was shown three ways , all good.
                    Couldn't realy love any of them. Finally had to weld for ten hours.
                    And four the next day. So many problems, keeping from melting
                    the Babbitt out of the bearings, that I never noticed
                    SHA-ZEN !!
                    It clicked now it works automaticly.
                    vg
                    sigpicViceGrip
                    Negative people have a problem for every solution

                    Comment


                    • #11
                      Originally posted by vicegrip View Post
                      I'm not sure what Zen should mean, but in metal-working
                      if one has any buisness doing it at all, and sticks with it.........
                      Something happens, and you find a junction of man / motion & metal.
                      Phil, there are some times that you say things in a way nobody else could put it---

                      You DO know what the zen thing is, you just did it with words--

                      Comment


                      • #12
                        Originally posted by Sberry View Post
                        ... I tried to get one to undercut bad but just cant seem to do it. This is about my favorite lo-hi weld, I like it better than flat. Its just so neat when you can get the bead to flatten out, no droop.
                        It is so hard to weld bad, when you're so used to welding good.
                        Arcin' and sparkin', Rocky D <><
                        Experience is something you don't get until just after you need it.
                        IF YOU CAN READ THIS, THANK A TEACHER...
                        IF YOU'RE READING THIS IN ENGLISH, THANK A SOLDIER!

                        Comment


                        • #13
                          Originally posted by calweld

                          The more you "try to direct your heat away" from the undercutting, the more undercutting you will get.
                          Originally posted by TEK View Post
                          Good catch---

                          As 5quarter and calweld are saying, rod angle means a lot...

                          Think of it as a straw, shooting your fill metal where you want it...it IS a zen thing(thanks Roger)....

                          If you get undercut on the left,lay the stinger more horizontal, shooting to the left, and slow down a taste, it'll fill---

                          When I stick weld with 7018, that rod/stinger combo is never in the same position for more than seconds...I am watching the puddle, reacting to it automatically....watch your puddle, watch that it doesnt get too long, too short, go to the left or right, make a perfect puddle, life is good---

                          This is a good clear explanation here - thanks.

                          I know this is an older thread but on my current project I undercut the heck out of my vertical piece. It's refreshing to see my plight posted and answered and I didn't have to post an ugly picture
                          Lincoln AC225
                          Lincoln Weld-Pak HD

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