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  • Porous, spattery steel welds

    Hi again! This time, I am trying to weld something with real strength, and I don't think this is working at all.

    TIG on rusted mild steel, ground off the rust then wirebrushed, plasma cut to fit. Right away something is weird: the bluing along the plasma cuts (pic), like stainless but without the hard sharp black slag. I've seen this on all my rusted stock beams and it always welds poorly, but this is angle steel I prepped well.



    Tried lanthanated tungsten as usual, changed to zirconium, but welds were always so spitting messy the tungsten got contaminated. Orange haze (pic) all over the welds, they're very porous and bubbly, you can hear them cracking even as they cool. I usually work with stainless and AL and have never had such probs tigging steel. Help/advice appreciated.

    Miller Dynasty 200 DX, air-cooled & footpedal
    Hypertherm 380
    Dinky Ingersoll-Rand compr. w/ line filter and condensation filter
    Lincoln O/A
    Electrolytic derusting tank
    Asstd powertools

  • #2
    I'm just a new tig welder but here are some ideas:

    1. I thought you said you CLEANED and "prepped well" the steel. To me this would mean not only removing the dross but also the rust in the area to be welded, and not with just a wire wheel but also a grinder and possibly a disc sander. I want to see SHINY METAL in the weld area for tig, and even that should be wiped with a degreaser before welding. Looks to me like you're trying to tig weld dross and rust together. I don't think that's possible.

    2. Was your argon turned on and was the argon hose not pinched under your foot or the foot of your stool? Because that brown ashy stuff in pic #2 looks like what I've gotten when I've forgotten to turn on the argon.

    3. You talk about wanting to make something with "real strength" ... what is it you're trying to make? Because that joint configuration doesn't look like something conducive to "real strength" ... but that might just be me.

    If you just want to slob stuff together like a caulk gun, can't you stick weld it with your tig machine? That's how I would attack the attempted weld you're showing...

    Hope this helps. Good luck.
    Last edited by Krunch; 05-13-2011, 07:36 AM.

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    • #3
      Plasma cut steel does not TIG well, in my experience. You need to grind the area down to clean, bare metal. Like Krunch suggested, grind the surface to clean, shiny metal. You'll get better results. Looking at the second pic you posted, I'm not sure that is going to yield a good joint. What are you trying to do? Fitment doesn't look real good.

      Dave
      Last edited by whateg0; 05-13-2011, 09:51 AM.
      Still building my new old truck - see the progress!
      http://www.ford-trucks.com/forums/65...-coe-idea.html
      http://www.hobartwelders.com/weldtal...ad.php?t=27017

      Square Wave TIG 200 - Woot!
      MM180
      SP125+

      Comment


      • #4
        Don't know what you're building but, it would look a whole lot better if you miter cut you're angle iron. Looks like it's more than 90 degrees. What ever you're angle degree is, cut each piece half of that angle. Grind it shinny (no rust pockets) and have a go at it. Make sure you're gas is on and the polarity is correct.
        sigpic

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        • #5
          Thanks...fit doesn't have to be good, and these are just tack welds. I didn't try to run a bead because this mess started happening.

          I'm only trying to lap weld the two pieces together on each side, not connect all three. I can flip this over now and clean it spotless, then properly weld the flip. So the fit isn't super but yeah, maybe the dross and slight residual rust is messing the weld. Interesting what you say, whateg0, since most of my trouble steel welds are on plasma-cut joints.

          I'm think argon is at 10 (psi?). Maybe that's not enough, I'll try more. This is going to be a chassis supporting a 75 pound cylinder and getting wheeled around. The steel is rusted worse than i thought (see the pitting), so I will grind and brush it spotless; just not sure how much will be left when I do that.

          No one thinks the weird bluing along the plasma cuts indicates anything?
          Miller Dynasty 200 DX, air-cooled & footpedal
          Hypertherm 380
          Dinky Ingersoll-Rand compr. w/ line filter and condensation filter
          Lincoln O/A
          Electrolytic derusting tank
          Asstd powertools

          Comment


          • #6
            Stick and 6010 will be your friend with crap like that.

            You're not even "close" to having it prepped for tig welding.
            SundownIII

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            • #7
              Yeah, 6010 SMAW is the ticket for this "aged" metal since no amount of prep will probably remove the pitting without serious thinning. Also, I am not a TIG welder, but I suspect the crap you're tack welding through or over will be drawn into the welds you do on the other side and contaminate them too. That's generally what happens with SMAW. The entire area around the joint on both sides needs to be properly cleaned and prepped before you strike the first arc.
              Blacksmith
              Stickmate LX AC/DC
              Big cheap (Chinese) Anvil
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              • #8
                Please do not take my statement offensively but, I would be ashamed to have a frame with a joint like that.
                Do yourself a favor and miter cut the corners.
                Start at 20 cfh for your gas. The bluing just means it got hot.
                Don't you have a stick welder or can your tig stick weld as well?? Use 6010DC or 6011 DC/AC rods. Grind them joints!!!!
                sigpic

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                • #9
                  Ha!

                  Ha! I knew I would be razzed for putting up an embarrassment like that. But I only know DC and AC tig and oxy/acet, welder can do stick but I doubt I could easily get materials esp. on a weekend. Steel is so finicky! I made a long table out of the same quality stock with oxy/acet and the welds were vastly better with site prep. On the rare occasions I've tigged it I've had clean material. I bet the spitting when welding was rust hidden in pits popping out when the good steel liquified. Think I'll learn stick anyway to help me get rid of so much rusty steel.

                  I cleaned up the weld sites on the other side and tried again with 15 cfh gas, nominal improvements. I think they'll hold which is all I was really looking for. If any of you are ever in the area you're welcome to have a laugh at this, what looks like drunken arc welds
                  Last edited by bomscho; 05-13-2011, 05:50 PM.
                  Miller Dynasty 200 DX, air-cooled & footpedal
                  Hypertherm 380
                  Dinky Ingersoll-Rand compr. w/ line filter and condensation filter
                  Lincoln O/A
                  Electrolytic derusting tank
                  Asstd powertools

                  Comment


                  • #10
                    I wouldn't worry too much about the appearance, as long as you are making good welds. In this case, the welds aren't any good either, so I guess that make you an oh-fer. Anyway, a buddy of mine had a frame plasma cut for his English wheel. He likes to TIG everything. Fine by me. Anyway, he fought porosity for a good portion of the frame while getting it tacked together. He ended up having to grind a weld out for some reason. After that, that area welded beautifully. So, then he went and ground the rest of the edges and they all welded great. So, yes, TIG welding plasma cut joints can cause grief. The rust will contribute as well, as others have said. For MIG, stick, and O/A, you can often get away with less than ideal prep. TIG has to be clean, though.

                    Whereabouts on LI are you? I used to come up there about 4 or 5 times a year for a few years when I was supporting a product that we serviced in Plainview.

                    Dave
                    Still building my new old truck - see the progress!
                    http://www.ford-trucks.com/forums/65...-coe-idea.html
                    http://www.hobartwelders.com/weldtal...ad.php?t=27017

                    Square Wave TIG 200 - Woot!
                    MM180
                    SP125+

                    Comment


                    • #11
                      Thanks, this has all convinced me to learn & use stick in future for rusty or plasma-cut mild steel welds. I usually plasma cut parts so this is key advice..

                      But in reading about and looking for SMAW "torches," I realize I don't know what they're called (they're not really torches), so I can't find the one that connects to the Miller 200 SD to price it out.

                      I'm in Floral Park. A short drive to some good scrapyards, and tolerant (occasionally even encouraging) neighbors
                      Last edited by bomscho; 05-13-2011, 08:54 PM.
                      Miller Dynasty 200 DX, air-cooled & footpedal
                      Hypertherm 380
                      Dinky Ingersoll-Rand compr. w/ line filter and condensation filter
                      Lincoln O/A
                      Electrolytic derusting tank
                      Asstd powertools

                      Comment


                      • #12
                        Why not just use your grinder to dress the edge that was cut with plasma??? You need to clean up the metal anyway.

                        Dave
                        Still building my new old truck - see the progress!
                        http://www.ford-trucks.com/forums/65...-coe-idea.html
                        http://www.hobartwelders.com/weldtal...ad.php?t=27017

                        Square Wave TIG 200 - Woot!
                        MM180
                        SP125+

                        Comment


                        • #13
                          Dave, I did that on the other side. Ground down even past visible pits, and cut a mm away from where the plasma had contacted. Still got ugly welds, but stronger-looking, and without the high-pitched "ping" sounds of welds cracking inside. I think this angle iron is so far gone I'd need stick to be sure of welds. I'm going to finish building the thing that goes on this chassis and repair the welds when I can get the electrode holder later.

                          It seems like electrode holders are all interchangeable and cheap. I wonder if I can just buy a generic one on ebay and use the TIG ground clamp.
                          Last edited by bomscho; 05-13-2011, 09:58 PM. Reason: Add electrode holder question
                          Miller Dynasty 200 DX, air-cooled & footpedal
                          Hypertherm 380
                          Dinky Ingersoll-Rand compr. w/ line filter and condensation filter
                          Lincoln O/A
                          Electrolytic derusting tank
                          Asstd powertools

                          Comment


                          • #14
                            Originally posted by bomscho View Post
                            But in reading about and looking for SMAW "torches," I realize I don't know what they're called (they're not really torches)
                            They're not "torches" – they're called "stinger clamps" or "electrode holders" and they look like this ($8 at Harbor Freight):



                            You clamp a welding rod or "stick welding electrode" in them (stick welding electrodes have a coating of flux that when heated creates your shielding gas/slag) and weld away. For your purposes I would recommend 1/8" 6011 welding electrode as a start.

                            Assuming your TIG machine can do stick welding, you should be able to find an electrode holder, some copper lead and some 6011 at Tractor Supply on a Saturday...
                            Last edited by Krunch; 05-14-2011, 10:22 AM.

                            Comment


                            • #15
                              Using Tig on angle iron is like putting a diamond necklace on a vagrant. It might fit, but it don't wear well.

                              Clean, prep and 7018 LH DC reverse polarity. (after dressing the ugly, misaligned, malformed joints).

                              From the looks of the cuts, your plasma is either running too low on amperage, has a poor ground to material connection, has contaminated consumables or you are twitching on the cut...or all the above.

                              The 'stinger' in the preceeding post is the proper method.
                              So little time...So many machine tools.........
                              www.flipmeisters.com

                              Miller, Hobart & Lincoln TIG/MIG/-
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