Outside corner setup for pulse mig on 2mm aluminium

  1. hotponyshoes Member

    Messages:
    1,667
    Location:
    Somerset. Uk
    I need to do some long runs on 2mm aluminium sheet.
    Planning to use pulse mig,
    Normally I would set it up inside corner to inside corner so I have 2x 2mm faces to weld against.

    In this case I would like some location tabs/slots cut into the sheets which rules out corner to corner setup.

    So I have a few options,
    Recess the slots for the tabs by 1mm so I am left with a 1mm face to weld against a 2mm face (red=weld bead)
    15790116796727876614115921572866.jpg

    Recess the slots by 2mm and run along the face
    15790119202863723606849825772524.jpg

    Or cut holes for the tabs so they slot through and leave a overhang for a fillet. 15790123125221616840156273663324.jpg


    Option 1 looks like the best bet to me although the sheets are over a meter long and trying to hold them within 1mm over that distance might be a challenge but I am thinking I can put tacks on all the tabs then weld the joint runs up.

    Option 3 might be the easiest way to hold everything in place but i am concerned i will end up with a distorted edge on the stick out unless i clamp a backing bar to that as well somehow.

    Any tips?
     
  2. Brad93

    Brad93 M J B Engineering

    Messages:
    6,552
    Location:
    Essex
    You’ll need to use a copper backing bar.
     
    hotponyshoes likes this.
  3. Hood

    Hood Forum Supporter

    Messages:
    9,906
    Location:
    Carnoustie, Scotland
    Option 1 for me. Tack it well then backsteps of about 100mm would be the way I go.
     
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  4. hotponyshoes Member

    Messages:
    1,667
    Location:
    Somerset. Uk
    I was planning to use a length of stainless angle for the backing as A, I can hold it at both ends and, B, I don't have a 1m+ length of copper!

    I am planning on putting the tabs about 100mm apart and thinking if I go with option 1 then I can put the tacks on the ends of the tabs leaving the open corners clean and empty for welding
     
    Hood likes this.
  5. Munkul Member

    Messages:
    1,143
    Cumbria, UK
    you're an ambitious man, running MIG on 2mm edge welds, even pulse MIG ;)

    The stainless angle should help a lot. Presuming you have a pretty nice pulse program. My Miller would just make a mess of 2mm edges... or maybe it's just me.

    Can I ask why you don't want to TIG it? You could absolutely fly along those lengths with TIG.
     
  6. Hood

    Hood Forum Supporter

    Messages:
    9,906
    Location:
    Carnoustie, Scotland
    I would say Tig would impart more localised heat into the job and distort things a lot more than pulse Mig.
    I personally would use super pulse (double pulse) but I don't think @hotponyshoes has that option on his welder. Having said that single pulse should not be a problem.
     
    Munkul likes this.
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