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  1. #1
    Silver Member
    Join Date
    Feb 2011
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    227

    Thumbs up "Burn Backs"

    Okay, I can weld a little bit and sometimes I can lay a good bead. My worst beads come on the inside of a "V". That is when I get the majority of my burn backs. What causes that? I do my best to have at leeast a 1/2-3/4" "stick out" but yet I get burn backs tha stick to the tip pretty hard. That is when I am getting most of my birds nest at the feed roller and beginning of the hose liner. Will try to take a picture tomorrow if I can remember it.

    Thats guys, for all the help you have given. It nice to be able to just sit down and ask a generic queston and get so many "non-generic" answers. I appreciate that so much.

    Lee

  2. #2
    Platinum Member
    Join Date
    Oct 2010
    Posts
    534

    Default Re: "Burn Backs"

    Your stick out sounds ok, make sure the contact tube is inside the nozzle by 1/4" or so, it'll prevent direct contact to the workpiece.
    When you set up your drive roll tension, keep your lead straight and back off the tension so you can stop the feed with a bit of resistance on the wire. That way it'll slip before it birdnests. It might take a bit of fine tuning so it doesn't slip when you don't want it to.
    Check your guide sleeve, the sleeve that the wire goes thru before going into the guide rolls. If you don't use wipers it'll eventually get loaded with wire/rust dust and put unnecessary drag on the wire.
    Make sure you have the right size as well as correct drive wheels, smooth for hard wire, knurled for flux/metal core.
    Check your liner, again if you're not using wipers the crap will build up in the liner. Good practice is to blow it out whenever you change rolls of wire.
    Proper size contact tube and liner.
    We were buying wire at work (govt so it was the lowest price winner) and it was crap. Wasn't level wound and was an inconsistant diameter so it fed like crap, couldn't weld for more than 5 minutes before it birdsnested. What they saved on wire they paid out triple in time and contact tubes.
    Take your lead off the machine and push the wire thru it by hand to check for drag, there should be none. I f there is it's either plugged or been kinked/dented.
    Make it a practie to keep your lead as straight as practical when welding. get into the habit of taking the bends out before you start, it'll become second nature after awhile.....Mike

  3. #3
    Elite Member Shield Arc's Avatar
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    Default Re: "Burn Backs"

    In dealing with burn back, my first thought is not enough wire speed. Or the flip side too much voltage. Is the puddle real wet / flowing?
    With Mig I run about 3/8 inch stick out. Gas less flux core about 1/2 inch, flux core w/gas, (dual shield) about 3/4 inch stick out.


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    2 Lincoln LN-25.
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  4. #4
    Veteran Member deereman75's Avatar
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    Default Re: "Burn Backs"

    On the weldingtipsandtricks videos I saw about mig welding, it said to have the contace tip stick out about 1/8 of an inch from the nozzle, not recessed.
    Never carry gasoline in your car trunk. If you do, atleast use some sort of container.
    -red green

  5. #5
    Elite Member Shield Arc's Avatar
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    Default Re: "Burn Backs"

    Quote Originally Posted by deereman75 View Post
    On the weldingtipsandtricks videos I saw about mig welding, it said to have the contace tip stick out about 1/8 of an inch from the nozzle, not recessed.
    I seen that a few months ago, I tried it. It really does make a difference!


    Miller Dynasty 300.
    Lincoln V350-Pro w/pulse.
    Lincoln LF-72 wire feeder.
    Lincoln SG Spool gun.

    2 Lincoln LN-25.
    1937 IdealArc-300.
    Everlast PowerArc 200.
    Everlast PowerArc 300.
    3 Lincoln SA-200s.
    1800 Ellis saw.
    Hypertherm Powermax 1250, CNC table.
    PROFAX Welding Positioner.
    JD2 model 3.

  6. #6
    Platinum Member
    Join Date
    Oct 2010
    Posts
    534

    Default Re: "Burn Backs"

    ....have the contace tip stick out about 1/8 of an inch from the nozzle
    It does make a difference but if you're not used to it you'll be holding a short arc all the time as well as the occasional touch to the worksurface. That's why I didn't mention it, I was assuming the op was not used to it....Mike

  7. #7
    Veteran Member
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    Iseki TA 247. Husqvarna 54",Gravely Zero, Cub Zero,.Polaris 850 ATV's Stihl 018 026 Pro, 029, 034 Super AV, 039, 044 Mag. Stihl Pole Saw.

    Default Re: "Burn Backs"

    You can buy nozzles that are flush, recessed or protruding of the tip. It's what ever the operator likes. Myself I like a 1/8 recess..Just make sure your wire speed is set right. Or on Twin Pulse, Set a little negative voltage trim.

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