Some mild steel outside corners

  1. Tom_ERST_S2 Member

    Messages:
    27
    Location:
    England, Cambs
    first time I’ve picked up a torch in around four or five weeks, can’t remember exactly, due to being away with work. Seeing as I’ve got two weeks off I decided I’d knock a fire pit up for the summer. All was going well until I had an issue. The steel started to fizz and spit and I ended up with some hideous holes in the weld bead.

    I’d cleaned everything up with acetone after I’d cleaned the metal with an abrasive flap disc and even used a stainless wire brush. All filler was cleaned down as well as the stuff I have is honking straight from the pack.

    Now as I’m a novice I can’t begin to figure why this happens so hopefully someone here will have the answer. If it’s down to me then I want to know so I can square it away as it ruins what was quite a nice run. 5A3BE498-AFF8-400D-90CF-D8F8C1DBFB10.jpeg E07F72DE-8917-40D2-A9F8-4B60E8ED347A.jpeg

    This was an outside corner on 3mm cold rolled sheet, 80 amps. The pops happened before I even got filler into the puddle so doubt that’s the cause. Any ideas peeps?

    And lastly some of the other runs. I did a bit on pulse, .7 frequency, 100 amps, 33% on time, 33% background current. Quite liked this as it gave me a nice little rhythm to settle into.

    8A5C4794-4DF8-4CCB-BDE6-795EA4CE9A20.jpeg 598BCA05-5169-479D-AEA3-7E96EC9FE555.jpeg

    Cheers

    Tom
     
  2. Richard.

    Richard. Member

    Messages:
    18,006
    Location:
    Cambridgeshire
    That’s a shame that’s happening Tom. Those are lovely neat outside corners there. It’s nice to see the tuition has got you off to a flying start.
    Ref your holes it’s definitely a contamination issue. I can see that from the porosity in the two spots. Sounds like you’ve covered all basis on the prep front but what is the back side like. Any scale or contaminants on the back will do this as you arc through into them.
     
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  3. Tom_ERST_S2 Member

    Messages:
    27
    Location:
    England, Cambs
    Richard I did think it may be something being drawn through from the back. I cleaned both front and rear the same though I must've missed something somewhere. It's annoying as it seemed that things were going well then I get molten metal spitting all over the place. Not great but you live and learn. I'll take a look at the back side of the weld and take some photos in the morning. I stopped before I could finish up as I ran out of gas so got some more to do tomorrow.
     
  4. Richard.

    Richard. Member

    Messages:
    18,006
    Location:
    Cambridgeshire
    Also the cut edge matey.
    A tiny bit of rust or scale on the edge it’s self will be enough to cause you a problem
     
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  5. Tom_ERST_S2 Member

    Messages:
    27
    Location:
    England, Cambs
    Yeah seems that even cold rolled steel has scale on it. I welded in some corner supports for a grate this morning and had all kinds of nasties bubbling on the other side. Didn’t go great but it’ll get wire wheeled and painted over. I put it down to lesson learnt for the next time I have to weld mild. Either that or I’ll get a second bottle for the mig machine.

    I must’ve not cleaned the back side and the cut edges as well as first thought. Next time I’ll get the edges I want to weld cut on the guillotine to avoid any contamination from the cutting disc. Just annoying it happened in a little area as the rest went really well and really enjoyed welding it all up.

    I have a few modifications to carry out on the fire pit when I’ve found out how well it burns or doesn’t so I have plenty more opportunities to improve on mild steel.

    Cheers for the input @Richard.
     
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  6. Tom_ERST_S2 Member

    Messages:
    27
    Location:
    England, Cambs
    Got the fire pit mostly done today, few little bits I want to do extra but for now it’s burning away nicely
    E0E7AE32-DDCD-45FB-AD12-DBABA42ED17A.jpeg

    Needs a base which is next on the list, then some handles and a motorised rotisserie to cook with. That little lot should keep me busy with a few different joints.

    cheeRS

    Tom
     
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