Help with Learning MIG Welding Please!

  1. reessi New Member

    Messages:
    12
    Location:
    sheffield, england
    So I have watched many videos and been practising. I am preparing to weld some patches on my campervan that were all down one side of the roof under the high top that I removed.

    Please see the photos. When I weld the manual states use gas mark 4. This results in bad pitting etc and porous as expected when not using gas. It only seams to work in full gas at mark 6.

    So do you think there is a problem with the valve? I am using a disposable bottle. When I weld some of them look correct as in smooth on full gas but there is black soot around the blobs which I have to keep removing with the wire brush otherwise it makes bad welds when filling in the gaps.

    Is it normal to have to keep cleaning off?

    Anyway it all seams a bit of a mess. Is my stickout correct as per photo? Is my clamp making good contact? It does not seam very meaty and not loads of contact with the teeth. I bought a new one but then lost it! Going to look for it this afternoon.

    How long is this disposable bottle going to last from Machine mart -its the 110l one.

    Can anyone recommend a place for a big bottle in the uk?

    What about this:

    https://www.gas-uk.co.uk/argon-5-10-litre.html

    It says it is for thin steel, it is 66£ before deposit.

    Do you think I need it, the holes on the van are all down the length of one side where the side meets the roof.

    If I buy a big one, what size is recommended? How long do these last, I know it is hard to be exact. Also since there is a deposit I do not want to get lumbered with loads of spare gas on return.

    Any advice welcome for the welding or gas bottles etc.

    This is my welder with 0.6mm wire:

    https://www.machinemart.co.uk/p/135te-turbo-mig-welder/

    Also I think I need a regulator, any advice what to get or where?

    I am in Sheffield if you know places for gas, I will do some research now as well.
    Also I am practising in my cellar. Will it be a problem to weld outside, will the gas just disappear!!

    What I noticed was that after scrubbing it with the wire brush it didn't look too bad and it came up ok with the grinder but has it properly penetrated? It seams strong when I try to bend it.

    Cheers.
     
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  2. reessi New Member

    Messages:
    12
    Location:
    sheffield, england
    The very last photo is the back and the second to last is the front after grinding. The third to last photo is before I filled in all the gaps!!
     
  3. gaz1

    gaz1 Forum Supporter

    Messages:
    8,882
    Location:
    westyorkshire
    what your getting with disposables is poor gas coverage with those disposables its full on
    also only lasts 5mins or a little longer

    there not really that good to use

    also better to have a contract bottle will last you a whole lot longer and be alot cheaper

    boc or hobby weld contract or other

    with a bigger bottle you will need a regulator and a pea guage to check the flow

    8 to 14 with the pea guage to check your flow
     
    stuvy and 123hotchef like this.
  4. reessi New Member

    Messages:
    12
    Location:
    sheffield, england
    This is what I was thinking. Is the stickout correct? Now when I start the weld I assume I pull the trigger and let the wire hit the side connected to the earth, then do I move from side to side to make the but joint as on the first spot the other piece is not earthed or should I be connecting the 2? On the ban though I will mainly be just having overlapping patches as it will not be seen under the high top.

    Also when you press the trigger a little bit I hear the gas, should I hold the trigger in a bit first and wait for the gas to surround it before pulling it harder to engage welding? Or is that not neccesary?

    Now what about sealing the welds after, I have no access to the otherside as the roof is double skinned, I make be able to reach along when theres another hole next to is and spray in some epoxy primer.

    What would happen if I put a small bead of polyeuranthene (I have alot of this ready to stick the high top on) on the back of the patch around it but not right on the edge so that it seals the weld in from other side. see picture. pretend that the picture is a new cut out patch ready to weld on and that is the back, That way moisture cannot get to the weld of the back is already painted??
     
  5. gaz1

    gaz1 Forum Supporter

    Messages:
    8,882
    Location:
    westyorkshire
    5mm stick out yours is too long for your settings

    and also closer to the work piece

    if welding thin metal its trigger pull thicker metal its a weave to a degree
     
  6. reessi New Member

    Messages:
    12
    Location:
    sheffield, england
    Thanks but what does "trigger pull thicker metal its a weave to a degree" mean?
     
  7. reessi New Member

    Messages:
    12
    Location:
    sheffield, england
    What size bottle would you recommend? I know its hard to know exactly, I have to weld patches about 3 inch x 2 inch most of the length of the van with say a few inchs between each one.
     
  8. gaz1

    gaz1 Forum Supporter

    Messages:
    8,882
    Location:
    westyorkshire
  9. reessi New Member

    Messages:
    12
    Location:
    sheffield, england
    cheers
     
  10. reessi New Member

    Messages:
    12
    Location:
    sheffield, england
    so a pea guage is the regulator with one dial and one tube with a ball in it? Whats the difference with using that and the ones with 2 dial guages which are more commonly sold it seams?

    cheers.
     
  11. gaz1

    gaz1 Forum Supporter

    Messages:
    8,882
    Location:
    westyorkshire
  12. reessi New Member

    Messages:
    12
    Location:
    sheffield, england
    cool. that makes sense.
     
  13. Shedendman

    Shedendman Member

    Messages:
    3,683
    east sussex
  14. Shedendman

    Shedendman Member

    Messages:
    3,683
    east sussex
  15. eddie49 Member

    Reessi, you're right, that work return clamp is rubbish, especially supplied new with a £300 welder !
    Stickout, gas, tutorial, practice : ditto what others have said. Buy or rent the largest gas bottle you can afford, I'm sure you will use it all.
    You need to hold the torch shroud much closer - right up against the work.
    Are you using an auto-dimming helmet? ( Highly recommended ).
     
  16. reessi New Member

    Messages:
    12
    Location:
    sheffield, england
    Thankyou everyone, I will read those articles and sort out a gas bottle. I have an auto dimming mask from machine mart.... I'll post up a follow up in a few days.

    Any recommendations for sealing a patch when not accessable from the other side? I will paint the back of the patch first. The patches will simply go over the hole (wider than the hole) since it will never be seen again under the high top.
     
  17. chris y Member

    Messages:
    239
    Durham England
    Making the patch bigger than the hole is considered a bit of a bodge, but if it'll never be seen then its your choice.

    Either way you really need to get to the back of it after welding or it'll be rusting again almost immediately from the inside out, and those overlaps will trap moisture and rot out fast.

    If you cant get to the back then consider drilling the panel behind it which will presumably be covered with trim and inject cavity wax of your choice, or find an aperture where you can inject from anywhere nearby depending on the length of your cavity wax injection hose.
     
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