Problems mig welding thin aluminium

  1. MoreWellie Member

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    1,150
    Location:
    Bedfordshire, UK
    Reasonably ok with my mig welding on steel including repairs to rusty bodywork but I made my first attempt at aluminium bodywork and it was a dismal failure

    From searches I may have been a bit optimistic but I have been asked if I can fill a hole cut for an exhaust in a land rover tub so this was vertical as well

    This is about 1.3mm thick and I am using .8mm 5356 wire with argon and I couldn't even tack it despite having a sheet of steel clamped to the back of this to try and prevent blowthrough

    I sanded back to clean metal and then used a new stainless brush in one direction only prior to welding.

    I don't have ac tig and have no experience of tig anyway

    I had one tack that was decent at 11pm everything else was pants

    IMG-20200712-WA0007.jpg

    My other thoughts are to joggle a large sheet to fit in the hole and enlarge the drilled holes and plug weld it in place and then fill

    or even to rivet (it is a land rover) a joggled sheet in and then fill

    anyone have any suggestions that may speed me towards success
     
  2. willie.macleod

    willie.macleod Member

    Messages:
    177
    Location:
    Western Isles, Scotland
    Is it feeding the filler wire OK? You haven't blown any holes and it looks like most of the tacks are lacking filler metal. Make sure you have a good tip of the correct size in the torch, double check the rollers are gripping the wire correctly as the wire is a bit softer than steel so can deform if it is too tight and slip if it isn't tight enough.
     
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  3. hotponyshoes Member

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    2,448
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    Some land rover alloy is funny stuff, the older ones were birma-brite or something. Don't remember what grade that was equivalent to but somebody else might?
    I know I had problems tugging a series 1 which disappeared when I changed filler.
     
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  4. Mr Roo

    Mr Roo Member

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    283
    Location:
    Edinburgh
    and bear in mind, you want clearance in the tip for ally. we used to use a 1.4mm tip for 1.2mm wire.

    Overall though OP, I can't foresee much joy MIG welding 1.3mm aluminium, regardless of grade... @Hood may disagree though!
     
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  5. Hood

    Hood If it walks like a duck....

    Messages:
    11,349
    Location:
    Carnoustie, Scotland
    A proper aluminium weld on 1.3mm sheet and there is no chance of doing that with a standard mig, which I assume is what the op has, a pulse mig and not an issue but unlikely that is what we are taking here.

    A series of blasted in spot welds is likely possible if there is a backing although I would be using stainless rather than steel.

    A very cold weld is also possible, it wouldn't be strong or nice and very spattery as it would have to be dip transfer but it may do for this application as likely it is going to be ground smooth anyway and unlikely to need to have anything more than minimal strength.

    No idea what grade it would be on a land rover but maybe 1050 would be a better choice although that would then be harder to push as it is very soft in comparison to 5356.
     
  6. hotponyshoes Member

    Messages:
    2,448
    Location:
    Somerset. Uk
    Maybe you could cut the center piece down by a couple of mm, put a 3mm or so sheet behind and try a series of tacks onto the thicker bit through the gap?
    Or glue a sheet in behind, glass it and finish with filler. If its anything like the landrovers I see none of the other bodywork will be anything like straight anyway!
     
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  7. tom2207 Member

    Messages:
    1,568
    Location:
    uk northern ireland
    what gas are you shielding with pure argon?
    land rovers are a pita to weld , Duralamin / Permabrite or some odd alloy , and at those thicknesses not a mission , ac tig maybe , or oxy acet , or find a wing.
     
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  8. Rrobson

    Rrobson Member

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    109
    Location:
    West Yorkshire
    A quick google search suggests birmabrite was used on pre-1980’s bodies and it’s a 5000 series alloy. The later stuff seems to be a bit of a secret although some suggest a 3000 series. I can’t comment personally because I’ve not tried to weld a land rover body, but what I do know is aluminium is a pain at the best of times!
    From your pic you seem to be melting the repair patch but it’s not wanting to adhere to the panel. You may have some success if you put a decent heat sink beneath, you’ll be able to spend a little longer trying to melt the panel and fuse the two together. If i was trying to weld that, having had little success with 5356 I’d be tempted try some 4043. It may not be an option for you though.
     
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  9. MoreWellie Member

    Messages:
    1,150
    Location:
    Bedfordshire, UK
    standard oxford mig
    Pure Argon
    .8 wire 1mm tip plain feed roller
    Wire feeding fine although I cannot set the tension low enough to be able to stall it. Any lower and the adjuster pops off the end of the the thread
    I picked 5356 as various searches suggested that was best for birmabright
    It occurs to me that the patch piece came from a newer panel which is unlikely to be birmabright
    I will also pickup some stainless for heatsink although I suspect that whatever i try with the kit I have the result will not be pretty
     
  10. Hood

    Hood If it walks like a duck....

    Messages:
    11,349
    Location:
    Carnoustie, Scotland

    If I am understanding what you are wanting to do, patch and grind flat, then does it matter if it is pretty?
    Personally I would go down the spray transfer and tack, tack, tack route rather than the dip transfer and cold spattery route but both would work although the former would likely be a stronger weld and less prone to cracking.
     
  11. Brad93

    Brad93 M J B Engineering

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    Location:
    Essex
    Put a piece of copper behind as a heat sink and up your wire speed. As hood says do spray tacks and join them all up,
     
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  12. DAPPH

    DAPPH as dyslexik as I'm daft

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    I'd cheat and cut two disc's one to fit the hole and one 25 mm bigger as a backing plate then draw a pretty pattern on both and drill out for using water sealing pop rivets and patch rivet it in place , having painted the mating faces with a sealant first . I do believe you can get counter sunk water proofed pop rivets these days . It would look classy and still be there if any one changes their mind and wants something like the old exhaust back on the landy .
     
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  13. arther dailey

    arther dailey Member

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    3,980
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    I think Dapph and other hit the nail on the head , why make work for your self , it as said is a landy , so pop rivets are the norm
     
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  14. Shox Dr

    Shox Dr Chief Engineer to Carlos Fandango

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    15,248
    Location:
    East Yorkshire
    Just like TIG, your biggest battle is Prep. That part is no way clean enough.
     
  15. slim_boy_fat

    slim_boy_fat Forum Supporter

    Here's a suggestion from a "know nowt" :ashamed:. If it's only to fill the hole and in no way structural, what about those filler rods that abound on eBay?

    Worked using propane - they've been discussed on here a few times. :scared:
     
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  16. tom2207 Member

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    1,568
    Location:
    uk northern ireland
    Really ?
    Even some land rover owners have a wee bit of pride left. Pop rivet a patch on is about as tasteful as big lumps of chequer plate on wing tops and door bottoms ...

    Oh hang on ,,, Pop rivet on some chequer plate and call it a feature , jobs a good un.
     
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  17. bletchmonster

    bletchmonster Member

    Messages:
    447
    Location:
    Cheshire. England.
    If you manage to weld it you are going to have some serious panel distortion to put right!!
    Having been been though this in the past I resorted to using epoxy panel adhesive to glue either a jogged patch or as suggested fasten a bigger patch behind then a snug fitting patch on the front to leave it level. I then reinforced it all with countersunk pop rivets. Tiny amount of filler will leave the whole job invisible.
    Feels like cheating but sorting out the panel warp after welding is a serious task.
     
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  18. arther dailey

    arther dailey Member

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    3,980
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    Yup some go for the ally plate eh ! all down to personal choice I geuss and what the customer is prepared to pay for ,with landy owners thats often the trip point...
     
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  19. tom2207 Member

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    1,568
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    They may not always be right ,,,, but they are always the customer.
     
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