Astra mk2 Floor pan

  1. Chris111mcr

    Chris111mcr New Member

    Messages:
    3
    Location:
    Greater Manchester
    Afternoon everyone,
    I'm new to the forum, my names Chris and I'm from Greater Manchester.
    I'm trying to plate over the holes in my floor pan, I have some sheet steel it's about 1mm thickness so thicker than the actual car body, when trying to weld with the mig it's just not sticking I've cleaned both surfaces up so much so I've gone through the floor a couple of times just trying to get it clean. I borrowed the mig off my mate it welded his VW fine but it's just splattering now and not welding the metal together
     
  2. Ashley Burton

    Ashley Burton Member

    Messages:
    4,489
    Location:
    Northamptonhire
    Have you got a good earth on the material your trying to weld would be my first question?
     
    metalmelt likes this.
  3. tom2207 Member

    Messages:
    2,034
    Location:
    uk northern ireland
    have you got the gas connected , and a good flow, ie bottle turned on .
    why not ask your mate to call past and show you how to do a bit in exchange for beer ., or chocolate , or both.
     
  4. Chris111mcr

    Chris111mcr New Member

    Messages:
    3
    Location:
    Greater Manchester
    I can weld though I've only ever used arc and oxy accetaline never mig,
    That's a good point we had the earth on the seat bracket but it's all painted up so I think I'll get a nice shiny clean bit to put the earth on,
    As I say I'm welding 1mm steel sheet to the car floor which I'd say is probably 0.8m maybe so that shouldn't cause it not to weld should it?
     
    metalmelt likes this.
  5. Ashley Burton

    Ashley Burton Member

    Messages:
    4,489
    Location:
    Northamptonhire
    @Chris111mcr Definitely make sure you've got a good earth. It's a night & day difference!

    Also a tip for your earthing point, Weld a tab to the floor & cut off afterwards
     
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  6. Chris111mcr

    Chris111mcr New Member

    Messages:
    3
    Location:
    Greater Manchester
    Ah ok cool thanks very much I appreciate the advice, sadly I'll av to wait till next weekend now to do as I'm on MOT training all week.

    Thanks guys
     
    Ashley Burton likes this.
  7. metalmelt Member

    Messages:
    381
    Location:
    UK
    I would recommend spot welding, raise your power a little and get a spot weld, move along and do another spot weld, and keep going until the panel is tacked in. Allow it to cool between a series of tacks and put more tacks between them until you have a series if tacks 1/2" (13mm) apart, once you have these then run stitches between them in sequences so it has time to cool.

    With thin sheet you use a series of tacks and short stitches.
     
    lewlux likes this.
  8. eddie49 Member

    Perhaps you are trying to sand or wire brush the rust away from the edges of the holes the original floor pan? It will never be truly clean and will contaminate the weld. After sanding, the edges of the metal will be so thin that it will burn through. You need to cut out all of the rusty area, going back far enough to reach sound metal that is rust-free.
     
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  9. Windy Miller Semi-Professional Potterer!

    Messages:
    2,908
    Location:
    North Kent, UK
    Decide where you want to weld and grind the metal clean BEFORE you cut out the rusty bit. This way you’ll have less chance of making the edge wafer thin.
     
  10. eddie49 Member

    Rather than sanding, flap disc, or grinding, a Poly disc ( polycarbide ) will remove paint without thinning the metal.
     
  11. The_Yellow_Ardvark

    The_Yellow_Ardvark perkele

    Messages:
    13,340
    Location:
    England
    The Astra bare body shell was dipped in a " Rust prevention solution" before paint.
    This can hinder welding on those cars.
     
    metalmelt and Nick DV like this.
  12. eddie49 Member

    From my experience of my 1992 Astra Mk III, I think it was dipped in "Rust enabling solution".
     
    Hopefuldave, jerrytug, McGeee and 5 others like this.
  13. chris y Member

    Messages:
    244
    Durham England
    Haha, very good.
    From extensive experience of the same era Vauxhall Carltons they definitely didnt test their rust preventing stuff before lashing it on, I bought my first very rotten Carlton in about 98, it was a 91 car and very rotten in the sills, wheelarches and chassis legs.
     
  14. The_Yellow_Ardvark

    The_Yellow_Ardvark perkele

    Messages:
    13,340
    Location:
    England
    I had a Mk2 2lt in that GM "Green" very little rust. But when you did find a small patch the weld was anightmare because of that dipping.

    I ponded 160 miles a day on that thing.
     
    Last edited: Oct 3, 2020
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