Good welds on sheet poor on bodywork

  1. Sparkysteve New Member

    Messages:
    6
    Location:
    Leicestershire
    Hi. Been practicing on sheet metal and have my technique near perfect and can lay nice beads and clean joins on the bench with fresh sheets.

    Then when I try to weld on my VW I get horrible blobs of weld and have to spend ages grinding down and rewelding.

    I have check and I have a good earth and metal is clean and the patches are New fresh metal and the body metalwork is clean and bright and solid (no rust)

    I have increased my gas flow as I am working outside and still it's horrible

    What is going on? Any ideas
     
  2. Shedendman

    Shedendman Member

    Messages:
    3,819
    east sussex
    You have to remember,welding on a bench,nice and flat is a far cry from welding out of position on a vehicle is a different story,this i know,i do it every day under motors on ramps with my head rammed in between exhausts axles and suspension,even one handed .
    A lot of it is down to setting your welder to suit,ie wire speed torch angle etc,adjust to suit.
    Those bits may look clean and rust free,but thats on the face if you have rust behind/below the surface then problems occur
    A few pics of what your working on with the problem may help us suss out things more;)
     
  3. Sparkysteve New Member

    Messages:
    6
    Location:
    Leicestershire
    Thanks for the reply.

    I agree that the difference between bench and in situ welding access is a major difference as access on the car is always much harder. Typically welding upwards from underneath the car.

    I am surprised that position makes such a difference. I increased my gas flow as I suspected that gas does not flow so well upwards.

    Looking at the welds they just seem to form balls of weld and not good flow or penetration.

    Could this just be the effect of gravity?

    Do I need to increase my power level to overcome this?

    I will try to get some photos examples.
     
  4. Burdekin

    Burdekin Chief Bodger

    Messages:
    4,820
    Location:
    Aberdeen
    Pics. Sounds to me like you have to turn the juice up.
     
  5. 8ob

    8ob Forum Supporter

    Messages:
    4,674
    Location:
    moscow on thames
    Sounds to me like the difference between the welder plugged in on the bench vs on the end of a long extension lead.Maybe a decent extension lead is in order or up the amps to compensate.

    Bob
     
    slim_boy_fat, Burdekin and fixerupper like this.
  6. fixerupper

    fixerupper Member

    Messages:
    1,517
    Location:
    Crete Greece
    Yeah, with my Clarke I found the extension cable made massive difference... I made up a thick 5 metre cable to use just out side the workshop door ..
     
    steveo3002 likes this.
  7. Burdekin

    Burdekin Chief Bodger

    Messages:
    4,820
    Location:
    Aberdeen
    I rarely change my set-up these days, for me it's the duration/speed of my welding that I just adjust whatever the position. You want enough amps to get 100% pen and a flatish weld. For me it's close to the limit of burning holes. I like to do a quick weld, with higher amps and then cool with compressed air as you go rather than lower amps. With mig you need to make sure you are getting full pen, so metal set-up and enough amps are important.
     
    slim_boy_fat likes this.
  8. Are you getting a decent earth connection, close to the weld site?
     
  9. chris y Member

    Messages:
    241
    Durham England
    Gravity wont affect the gas flow when working upside down or any other position, but has a big effect on wire, for car body welding with the torch pointing upwards I always find I need more wire feed rate.
    Typically for car work you are welding at quite low voltage / current and small changes make a big difference. After first checking that you have a good power supply (nice fat extension lead) and very good earth return clamp contact try increasing wire feed.
     
    Shedendman likes this.
  10. Sparkysteve New Member

    Messages:
    6
    Location:
    Leicestershire
    Thanks for all the replies.

    Had not thought about the extension lead. This could be a factor as I have to use a 15m extention lead as the wife complains about the draft when I use the socket right next front door!

    I will investigate an outdoor socket close to the drive or a much better extention lead.

    I think power could do with increasing to compensate and also play around with the wire speed as well.

    Experimenting on the car is not ideal but much better than grinding down crappy welds I suppose.

    Earth is always seems to be an issue but try to grind a clear spot near the weld.
     
  11. WorkshopChris

    WorkshopChris Forum Supporter

    Messages:
    4,649
    Location:
    South East Essex
    You could always practice laying on your back upside down running off you extension lead with some scrap material clamped on a axle stand.
    Nothing like getting practice in a close to re world situation, much more useful than testing on the bench.
     
    slim_boy_fat likes this.
  12. chris y Member

    Messages:
    241
    Durham England
    A good earth is very important, two things to do -
    if your earth clamp is weak or doesnt have copper inserts then replace it, they dont cost a lot and a decent one will have great clamping power and the copper pads will help contact.
    If you are having trouble finding somewhere clean and close by that you can clamp to just use an offcut of clean steel, weld it with a few tacks close to the repair and put your earth clamp on the tab. When you are finished break the tab off and grind the welds off.
     
    slim_boy_fat likes this.
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