Newbie asks for help...

  1. boDge Member

    Messages:
    8
    Northumberland. UK
    Hello all..

    My wife and I have recently started to restore a '73 MGB. We intend to do everything possible ourselves, including learning how to paint, weld, upholster etc etc.

    Anyway, I've just started to weld with a Clarke 130EN gas/gasless mig welder. I've got to the stage where I can blow holes in just about ANYTHING and would appreciate some advice. I'm practising on scrap sheet steel approx 3mm thick and I'm attempting to get a reasonably straight line.

    Using the circular torch technique I get an irregular weld (width varying from 1/4" to 1/2"). It would appear that the torch 'spits' when the wire makes contact with the metal. This appears to be causing the relative contact position of the wire on the metal to vary, hence altering the width of the weld...

    Does this make any sort of sense??
    Any suggestions??

    Regards,

    B.
     
  2. Hitch

    Hitch Moderator Staff Member

    Messages:
    12,277
    Somerset
    It sounds to me like you may have the wire speed set a little on the high side, either that of your holding the torch a bit far away, aim to have about 10mm of wire coming out before the weld pool.
    If that doesnt help, try doing a weld in just a straight line, opposed to doing a weave. See how that goes.
    Also it could be that as your doing the weld, the heat is getting into the sheet, and making the weld pool flow outwards. Solve this by turning your welder down slightly, or maybe move a little faster.
     
  3. boDge Member

    Messages:
    8
    Northumberland. UK
    Thanks for the fast reply..

    I'll try some 'variations' as you've suggested and post the results...

    Again, thanks.

    B.
     
  4. malcolm

    malcolm & Clementine the Cat

    Messages:
    9,125
    Location:
    Bedford UK
    1973 MGB. Lots of welding in one of those - good cars.

    I have a GT from 1970. I've fiddled with it a little - www.vord.net. Sadly it's going up for sale to help prepare for a house move. One of them had to go and it wasn't going to be the MGA.

    I can't really add to Hitachimad's advice, but do post pictures of the car/welding. Especially the car. Probably I should put some way of doing that onto the forum..... It's good to come across someone else who has to deal with "flitch panels"
    :shock:
     
  5. boDge Member

    Messages:
    8
    Northumberland. UK
    Just a quick update... I've bought some new flux coated mig wire..What a difference!! I can now produce a 'reasonable' bead and have managed to actually join 2 bits of metal together..

    I said to the wife "I should be able to start welding on the car soon.."

    She said "Just make sure that you start on the inner wing.. No-one will be able to see that!!" OUCH!!

    ttfn.

    B.
     
  6. Hitch

    Hitch Moderator Staff Member

    Messages:
    12,277
    Somerset
    I take it from that you were using normal wire, but no gas then...?
     
  7. boDge Member

    Messages:
    8
    Northumberland. UK
    No.. I'm not QUITE that stupid... I was only welding with gasless wire with the polarity wrong. I realised this when I tried .6mm wire with gas (doh!). The gasless wire supplied with the welder seemed very poor compared to the new stuff that I now have. Has anyone else found anything like this - or is it me ??

    Today I was reasonably successful drawing letters with the torch on new metal. I've successfully managed to fill drilled holes of various sizes in 1mm thick sheet.. ground them back and.. hey presto.. no sign of where the hole was. I've also had some success with butt joins, I've found these to be easier to do than the overlap joins.. all I get with these is a raggy edge :>(

    I then tried my first 'real' patch on one of the MG's front wings.. Total disaster, I'm back to 'bird poo' on the seams.

    Any suggestions would be appreciated.

    If it isn't raining tomorrow, I'll try some more.

    ttfn.

    B.
     
  8. malcolm

    malcolm & Clementine the Cat

    Messages:
    9,125
    Location:
    Bedford UK
    I've heard talk from the "sparks and brimstone" crowd about reversing the polarity when using fluxed wire. Does anyone know why? Also does anyone know how? - there is no handy button on my welder for this.

    Welding under a car is always more tricky than welding plate. The really important thing is to use an angle grinder to lightly grind all the rust and paint from the steel you want to weld to. Make the metal shine. Otherwise bird poo is tricky to avoid. Sometimes it's tricky to remove all the paint and rust with the grinder (or sand paper). In that situation a slight increase in power can help.

    Also I've found holding the torch with two hands, the second hand to steady the tip of the gun, and bracing an arm/wrist or fingers against something solid helps with gun control.
     
  9. Pentawelder Angle grinder operator

    Malcolm, you are correct the gun needs to be NEGATIVE for
    innershield welding (flux). I have a Lincoln and I switch polarity by
    opening the side panel and swapping the leads. That is the official
    way to do it, The cables are secured with wing nuts for easy switching.
    Innershield smokes a lot and the arc is brighter. White hot smoke I
    would guess is the cause. :idea:
     
  10. Hitch

    Hitch Moderator Staff Member

    Messages:
    12,277
    Somerset
    Yes Torch is + for gas, - for fluxed.
    My welder has 2 Dinze connections on the front, one for the earth, the other from the euro connector, you simply switch the two other on the front of the machine.
     
  11. malcolm

    malcolm & Clementine the Cat

    Messages:
    9,125
    Location:
    Bedford UK
    I found fluxed wire to be a complete pain - that'll maybe be the reason. I ended up giving the wire to a friend.

    So why do you need to reverse the polarity? I can't think of any advantage in having the electons flow one way rather than the other. But then I'm not an electronics guy. However the friend with the wire is. If it's not an obvious answer I could ask him.
     
  12. Pentawelder Angle grinder operator

    Malcolm, I believe it has something to do with the magnetic field generated whilst welding. Y'know like poles repelling, I just looked and can't find where I read it on the web. Damn electrickery ... I'm
    going back to oxy acetylene!!! No, now I remember I can make a bigger mess with gas.
    Gordon.
     
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