Am I pushing my MIG too far?

  1. v7john New Member

    Messages:
    5
    Location:
    West Wales
    Hello. I've just joined this happy band. I'm basically an ok self-taught occasional hobby welder. I can usually produce acceptable results but, as I only weld occasionally, I always have to do a little practice first.

    I'm having problems this time. I am trying to weld a 3mm thick tab to the side of a 14mm bar. Both mild steel. I keep laying a nice looking bead of weld but find I can pull the plate off with pliers and then pull the bead off the bar as well. Clearly there is next to no penetration. I have tried bevelling the edge of the plate without any improvement

    The welder is a SIP migmate 130 bought in the 90s and I'm using 0.8mm wire and pure CO2 as I usually do. I'm using the maximum power setting. I've tried slowing the wire feed until there's just enough to maintain an arc and moving the torch slowly in an effort to get as much heat into the job as possible without any improvement. It's foxing me because I have joined these two materials together in a different way for another job and, although it wasn't pretty, it did work that time.

    Is the job beyond my welder's capabilities or is it me? I sold my arc (stick) welder years ago and am beginning to regret it.
     
  2. rtbcomp

    rtbcomp Moderator Staff Member

    Messages:
    18,615
    Location:
    Sheffield UK
    Welcome to the forum.

    The current increases with wire speed, so try turning it up and see if that makes a difference.
     
  3. cumbriasteve

    cumbriasteve Moderator

    Messages:
    9,660
    Location:
    Cumbria UK
    Welcome to the forum:

    You could do the weld on full power coupled with as high a wire speed as you can cope with and it will 'stick' the plate onto the bar, it won't however be correctly welded, you don't have enough power for the correct penetration.

    You may even get it where it appears to be quite a strong weld and take a bit of a battering so suitable for a bit of garden ornamental work and that's about it, the chances of weld failure if under stress in the future are quite high.
     
  4. gaz1

    gaz1 Forum Supporter

    Messages:
    8,616
    Location:
    westyorkshire
    id have used an arc welder for that thickness to thinness
     
    eLuSiVeMiTe likes this.
  5. v7john New Member

    Messages:
    5
    Location:
    West Wales
    Thanks everyone.
    I had started my attempts with the wire feed turned right up so that's not the answer.
    I'll borrow an arc welder from somewhere as I want the joint to be strong. This particular weld won't be under a lot of stress but there will be others that will so, I might as well do the job right. I know this is the MIG welder forum but, would a 140amp arc welder be man enough? I noticed one in a friend's garage the other day.
     
  6. Arclikeharrypotter Member

    Messages:
    1,012
    Location:
    Northampton
    Yep 140A more than enough. Nice thing with stick welding is that you set your amperage to the electrode you're using.
     
  7. v7john New Member

    Messages:
    5
    Location:
    West Wales
    Thanks. I seem to remember using 90A for a 2.5mm rod. I got rid of the arc welder as I was mainly doing car body and chassis work. The MIG made that much easier but, I could make things out of angle iron with the arc. It's been at least 20 years so it will be interesting to see if I can still do it.
     
  8. gaz1

    gaz1 Forum Supporter

    Messages:
    8,616
    Location:
    westyorkshire
    if you do go back to arc then look for an oxford if you dont want to move it far if not theres digital systems nowadays

    i have both arc and mig set ups but i also have a transportable arc welder as well
     
  9. v7john New Member

    Messages:
    5
    Location:
    West Wales
    I've just found out that my son-in law has an inverter welder which he's happy to lend me and to show me how to use it. I didn't know he had such a thing being a carpenter! Bad news is it'll be a few days before I can have it. Still might try that one I spotted the other day but it's the old style like I used to own. I've been reading the Arc tutorial here and that seems to be the type not to have.
     
  10. cumbriasteve

    cumbriasteve Moderator

    Messages:
    9,660
    Location:
    Cumbria UK


    The forum is a meeting place for all types of welding plus other weird and wonderful subject matter so don't fear asking about arc welding.

    The arc welder you suggest is the type that's not the best will be a buzz box I should think, a little more difficult to strike up with but still very capable of doing the task you want to do.
     
  11. v7john New Member

    Messages:
    5
    Location:
    West Wales
    Collected the buzz box from my friends house today. He gave it to me as it turns out it's his "spare". He has another one and an oil filled job which was too heavy to move! He gave me a dozen 2.5mm Fincord M rods to be getting on with as well. I'll have to buy him some Scotch for Christmas I think. It's an old SIP Weldmate 140 with a 6/12/24V battery charge facility but it's not going anywhere near my AGM batteries.

    I'll try and get a few hours with it in the workshop tomorrow. Practice first methinks.
     
  12. Rig Pig

    Rig Pig Member

    Messages:
    3,500
    Location:
    Narrwich! U.K.
    Make him an offer for the oil cooled! They are brilliant old things.
     
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