A mate rang me at the weekend, and said "how's your welding skills" OK says I, what do you need welding?
Turns out it was a Midget wishbone mount, which had split. Now, his mig welder (can't remember the model) is a 130 amp thing with a live torch.
The wire feed seemed ok when not welding, but as soon as I struck an arc, the feed became very sporadic, almost pulsing. Adjusting the feed speed and
power made no difference. Couldn't get a decent weld to save my life!!
Any ideas what could be wrong?
Marcus
Wire size vs. tip size. It the wire is smaller than the tip you dont get good electrical contact and the arc will be hit and miss....That would be my
first check.
After that, I am not sure...
D.
Has the wire split? If the wire has a slight ribbon comming off it it might have clogged up the drive. Happened to me in evening class, many years ago.
Maby there is not enough tension between drive rollers. Is the wire in good condition, if its a bit manky then it won't feed well.
I had the same trouble in an evening class last week, my tutor told me to keep the wire running to the torch as straight as possible. Did it and it
worked a treat! I had it slightly coiled up and it made it more difficult to get pushed through. Might be the answer to the problem. Hope it helps
Had you got a decent earth?
Long shot but if any corrosion is on the wire it will drag and judder up the feed pipe and out of tip it happened to me when I used someone else mig that they had not used for a couple of years
quote:
Originally posted by Peteff
Had you got a decent earth?
Tried all of the above!! Earth was fine, even tried welding to the clamp!
Didn't look inside welder itself, could be dodgy contact I suppose.
I hear people slate small SIP welders for their wire feed, but ours is so much better than my mates. (105A turbo welded 2 chassis and even coped with
axle casing)
Marcus
Has the welder always done it. I've known some welders from new be complete swines, but a identical welder (make, model, etc) work beautifully.
Well that's got to be a good earth but it doesn't prove it's attached to the car 
You could weld to the clamp if it was laid on the
floor.
To get a deacent earth with the earth clamp on an old arc welder, you some times had to tack weld the clamp to the work peice.
Start the arc on the edge of the clamp and then move onto the work piece.
Then agin cheap clamp and rusty metal.
the answer must lie in one of the reasons above, but from my point of view (not helpful here!) this is the reason why my Clarke 150 TE mig went to a new owner, my big mig that I have now makes no such fuss, whereas the Clarke used to need constant fettling of the liner, the torch lead straightish, the wire utterly corrosion free, and a wd40 soaked scotchbrite pad bulldog clamped round the wireafter the feedrolls and before the liner end. Even then it was not good at even welds as the wire speed still tended to vary, but then it was only £200, whereas my new one was a very good bargain at £400 (sold by a big name at half that again +vat)