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MillerMatic 185 (MIG welder)

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  • MillerMatic 185 (MIG welder)

    Using the MM185 w/ Argon/25% CO2 shielding gas, I have for a long time had problems w/ my welds: excessive spatter & porosity. I have a hunch that the shielding gas isn't even getting to the weld sites. In general, I try to use clean mating edges for my welds. Is there any easy way to trouble shoot this and verify that the shielding gas is being applied?

    Is there a testing protocol to trace the exact cause?

    Is the 185 known for this kind of problem?

    Any helpful thoughts are appreciated.

  • #2
    I bought a MM185 in '99 and love it. Can you hear gas comming from the nozzle when you press the trigger? Make sure the gun is all the way in the front of the machine and the o ring isn't pinched or something. What wire are you using?...Bob
    Bob Wright


    • #3

      Yes, I actually do hear gas being expelled from the nozzle as it spits out wire.

      Hmmm... I'm just not convinced it's working as intended.

      Using nominal settings for wire feed & voltage, my welds are terrible.


      • #4
        Is your polarity correct? With the positive lead going to the drive and neg to your ground clamp.


        • #5
          Yup. Ground (BLK) going to the work clamp; positive (RED) to the wire drive mechanism.

          My nozzle is slightly consumed. I wonder how significant that could be.


          • #6

            If you are ever unsure of your sheilding gas a good benchmark is to start at the gas bottle, work your way through to the torch checking for leaks damaged O-Rings etc. I have pulled welds apart that looked great on the outside to find holes on the inside. I go back to the machine and check it over to find a leak. When gas flows through the line the leaks act as a venturi and drags atmophere into your sheilding gas.

            Hope this helps.


            • #7
              Indeed, Nick. This is exactly what a Miller guy just told me on the phone (not 5 minutes ago).

              Another odd possibility which I intend to investigate is the wire itself. I'm still on the original 10# roll (it's about half used up) and the guy suggested that just maybe, over time,the wire has acquired just enough oxidation to be problematic in getting a good, clean burn. It looks OK to the eye (rather like it did originally) - certainly I see no obvious rust. But for a few dollars, I may try a new roll and see how it goes. Some suggest that, when a MIG is not in use for awhile, the roll be removed and placed in a Zip-lock bag.


              • #8
                Post a picture of your drive roll set up, change the diffuser, check your input voltage and jumper.

                "When gas flows through the line the leaks act as a venturi and drags atmophere into your sheilding gas." Never happen! If you get a hole in your car tire it does not inflate, it deflates. If you get a hole in your garden hose water leaks out, air does not come in.These are positive pressure systems, running at low velocities, they can't suck in, they can only leak out. The way they create a venturi vacuum is by pumping high pressure air across an angled orifice into atmospheric pressure. The only way you achieve any portion of this is if you had a hole in the nozzle at the diffuser.


                • #9
                  Sorry I'm late in posting back but I've been wrapped around the axle.

                  Walker made a good point about the admonition posed by Nick Walkley - a point well-taken. It does make sense that a pressurized line - albeit little pressure - would not likely entrain air from without.

                  I appreciate all comments posted about my problem. I also went off and interviewed a Miller tech rep in Appleton, WI, as well as a local authorized Miller repair guy here in NJ. I even checked w/ a tech rep for Hobart Brothers (bought out McKay) for my welding wire. They all danced around pretty much the same likely factors. In pursuing this, I tried to explore all the obvious factors: gas flow, welding wire feed & quality, cleanliness of mating metal edges, etc. Everything turned out to be nominal.

                  That left only one thing: my technique. Interestingly, for excessive splatter, the Millermatic manual lists use less stickout as one of the top 3 corrective actions; for pososity it's one of the top 4. Both phenomena relate largely to insufficient shielding gas at the weld site. I did a fair amount of testing and found that, once I choked up on the weld site, I got better behavior in the weld joint. Ashamed to admit it but I believe my biggest problem was too much stickout! From my perspective, there's probably a good reason for this. (1) I grew up on a Miller stick welder. (2) I like to see what I'm doing at the weld site. (see #1). For the best result via MIG, it seems that minimal sickout is ideal and I find myself having more to trust the result (even when I can't really "see" what I'm doing, if that makes any sense).

                  Another issue is the cleanliness of my nozzle, listed as #2 for controlling porosity (Millermatic manual). I find I get a fair amount of spatter inside the nozzle and have to frequently remove it for scraping/cleaning. This really seems to help.

                  Don't mean to ramble too much but, in summary, I believe I (my technique) was my own biggest problem and now seem to be able to create some good (if not award-winning) welds.