Another Novice welder

  1. Father Ted Forum Supporter

    Messages:
    2
    Location:
    North East Scotland
    Hello, I have been given an old Sealey Supermig 180/1 and am going to have a go at restoring an MGB. I have read as much as I can from this forum, and managed a few welds. Most of the welding I will be doing, initially at least will be puddle / spot welding.

    First question I have is what size of hole to use? I have a tool ( a joggle jodle joggle...I can't spell it) that punches nice 5mm diameter holes which makes a nice neat job. elsewhere on this forum I have seen 7mm recommended or even larger.
    Is 5mm diameter acceptable for sills etc?

    I also have issues blowing holes in thin metal when trying to butt weld ( think about 0.8mm to 1.0mm thick...pieces cut from an old bonnet) I am practising on this now and assume it to be trying to weld for too long a duration and not moving the torch fast enough. I am thinking unless my technique improves instead of butt welding sheets together I might joggle (there's that word again) and overlap sheets and spot weld using 5mm diam punched holes (or 7mm diam?) to give a "safer process"
    Appreciate any guidance
     
    RTFM likes this.
  2. Wozzaaah

    Wozzaaah The wizard of woz Staff Member

    Messages:
    14,942
    Wiltshire, UK
    Hi and welcome to the forum. Those punches make a nice neat hole very quickly but I used to find the hole way too small so would put two adjoining holes. Not the neatest solution but at least the weld was sound.
    With a hole too small you run the risk of filling it with weld and not penetrating properly.
     
    Parm and Yamhon like this.
  3. Father Ted Forum Supporter

    Messages:
    2
    Location:
    North East Scotland
    Thanks for that...not a bad idea. make a rough elipse with two or three punches instead of drilling. What do you think about the merits of using an overlap with spot welds versus butt or seam welding?
     
  4. north Member

    Messages:
    44
    Location:
    Sweden
    Sweden here:drunk: . 5mm is not acessioable. use 8mm. Use high Power and be faster...Fry eggs...Listen to the sound.
     
    Parm likes this.
  5. Yamhon Member

    Messages:
    1,095
    Location:
    Earth
    @ OP, this guy shows you an approach for welding up holes in thin sheet, might be useful to you.

     
  6. eddie49 Member

    For MoT repairs to a vehicle, the choice is not a matter of preference, it depends on the rules:

    " The repair must appear to be virtually as strong as the original structure with only continuous seam welding being acceptable for patch repairs (even if the patch extends beyond the prescribed area).

    ยท spot welded joints are acceptable where the original panel has been replaced to an existing spot welded flange (provided the original defective panel flange has been removed). Stitch or plug welding is acceptable as an alternative to spot welding in these cases. "

    So if a full panel is being fitted, the original part was spot welded, and the damaged part has been fully removed, spot or plug welding is permitted. If a part panel, or a patch is being fitted, all cut edges must be fully seam welded ( at lap or butt joints ) except where it meets a flange that was originally spot welded ( e.g. the bottom edge of a sill patch ), where spot or plug welding is allowed.

    MoT Tester's manual:
    http://www.partinfo.co.uk/files/VOSA Inspection Manual Classes 3 4 5 & 7.pdf
     
    Parm likes this.
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