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MIG Contact Tip Questions

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  • MIG Contact Tip Questions

    I have questions about when to use contact tip setback (tip-to-nozzle)... or when someone would someone want to use a different styles of tips from the standard style (such as Cutback tips, Heavy Duty tips or Tapered tips)? I know the tips for my spool gun have a cutback in the face of the tip and I'm really curious as to the why of this...

    Is there advantages and disadvantages to each such as sheilding gas coverage, CTWD (contact tip to work distance), "heat vs. cooling" in short circuit transfer, globular transfer or spray transfer?

    I was told use a normal tip with flush to 1/8 inch setback for short circuit transfer... and a Heavy Duty style tip with 1/8 to 1/4 inch setback for spray transfer... but I've only guessed at the whys.

  • #2
    one of the biggest benefits of the tip sticking out of the nozzle or even flush is the ability to see the puddle. It gets to nozzle out of the way. This works great for inside corners, fillets etc. If it is really tight then you can go to the tapered tip and a tapered nozzle. I had one weld were the designer was a bone head and I couldn't get the nozzle into the area and hit the angle to weld. Didn't have a qualified procedure at the time for stick so we took the nozzle off, bent the tip slightly and used a shielding gas flood from 2 hoses on each side to provide gas. Worked great but I still had the designer fix the issue.

    Using a recessed tip I have found is best in breezy areas, not windy forget that. Also on outside corners or round parts where I still need a 5/8-3/4" stick out but will loose gas to quickly any other way.

    Yes stick out is very important. The wire has to reach a melting point temperature wise and it doesn't start heating up officially until it makes contact in the tube, then the temperature starts rising until out at the arc it finally reaches a melting point and can separate from the wire and become spatter unless your good enough to make it become weld.

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    • #3
      good answer diamond.

      Comment


      • #4
        That makes sense and I understand.

        I figured with most applications (especially fabrication), a standard contact tip and nozzle works well in all welding positions... with good shielding gas coverage, adequate pentration and maintaining a managable consumble's cost... But most fabrication I do is in the shop, in a logical assembly order, with nothing in the way of the torch to see and achieve a good weld.

        A percentage of the welding I do at work is "repairs" on heavy trucks and heavy equipment. I find myself contorted into a body position, in full leathers, with a MIG gun in one overhead position and my head looking from another angle (because I couldn't see around my arm), with slag coming down all round me... Sometimes I can't see what I'm welding while I'm welding it, so I'll stitch-weld it going off the sound of the weld, stopping to check my progress and how the bead looks. Sometimes I have to cut a temporary "access" hole to get just enough room to cut out a bad weld and to get a torch in to reweld it...

        Sometimes I can manipulate the welding position and access- and sometimes I can't and have to just get creative and work with what I have. Having to do this and to stay "creative," I now seem to have a collection of different style tips, diffuzers and nozzles (Tweco style slip-on and screw-on nozzles) which has kept my equipment adaptable and has made my job easier...

        I've used standard and HD contact tips. I don't have tapered tips, probably because I don't know anything about them and hense haven't figured out any instances where they might help me out...

        If something is going to make my job easier and consistantly save me time, that's an investment that helps me make money. For instance, having MIG torches set up with sized liners (.023-.030 and .035-.045) is a lot easier and less time consuming to "plug in" when switching wire sizes than the alternative. That makes me money.

        My Magnum 250XG spoolgun? Well I'm not sure why the tip on it is split in half and cutback for 1/4 inch... The problem with these tips is that I have to special order them from Lincoln. No one around here locally carries them. I've used the short Miller contact tips in it with a slip-on tweco nozzle and it works just fine. I don't "see" a difference in the bead. The Miller tip has a the same length feed ramp as the Magnum tips, where as the short Lincoln tips do not (causing some feeding problems with lighter gauge wire and with aluminum wire with the 16S tips).
        Last edited by MAFoElffen; 03-01-2009, 01:45 PM.

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        • #5
          So should I get more specific about this and divide it into 2 questions?

          (1) What is the purpose and uses of tapered MIG contact tips such as the Tweco 14T styled tips?

          (2) Why are Magnum tips cutback 1/4 inch?***

          Note: ***My guess here is that sometimes when using aluminum wire, the arc can falsh back to the tip in an instant. You can get the wire loose and bent it back into the cutback and save the tip(?) or so it seems...

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          • #6
            (1) What is the purpose and uses of tapered MIG contact tips such as the Tweco 14T styled tips?
            Without looking that particular tip up, tapered tips are for use with the reduced size gas nozzles. For instance if you went from a 1/2 inch ID nozzle to a 3/8ths inch ID nozzel for better visibility. Then the tapered tip would allow just a very tiny bit more room for the gas to flow and/or spatter build up and/or firing across to the nozzle in high amp situations. That later is if you happen to be someone who virtually touches the nozzle to the work piece from time to time like I do.
            Last edited by Sandy; 03-01-2009, 07:52 PM.

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            • #7
              Originally posted by Sandy View Post
              ...to a 3/8ths inch ID nozzel for better visibility. Then the tapered tip would allow just a very tiny bit more room for the gas to flow and/or spatter build up and/or firing across to the nozzle.
              Thanks Sandy. Questions answered between you and all- Thanks All (ie Diamondback).

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