Welder not working. Help?

[UKJeeper]

I have been given a mig welder (Snap on mig 130 turbo) in the hopes that i can fix it and use it.

Seems to feed just fine, as long as its not actually touching the work. The wire will feed through no problem. But as soon as you try and weld, it'll stop feeding. It seems to arc to the tip, like its not grounding to the ground wire, even though its a few inches away on bare, clean metal. I've checked the ground wire connections, all seems fine there. The rollers seem fine, touching a non-conductive surface, the feed wants to keep going, so its doesn't seem like its slipping or the linings worn. Its new steel wire, but i am using straight CO2 (the tank was free). Tip's the right size for the wire (0.8).

Any ideas on what i could be looking for?

[clbarclay]

It could be that the wire is earthing back into the welder.

The positive supply is connected to the tip the connects to the wire si it is just the last bit of weld wire that carries currect. If it arcs and sticks tip to wire no matter were the inteded earth in relation to the wire/tip then it seems likely that the weld wire is earth inside the welder.

[murph]

I have the same welder, done exactly as you describe a few months ago, I changed the liner, new tip still the same. I then changed the shroud and it cured the problem.

The shroud should have an insulator around the inside where it slips over the torch, this was worn and had slipped and left an exposed part which was causing the problem.

For the sake of a few quid its worth a go.

[burgerman]

I have the same welder, done exactly as you describe a few months ago, I changed the liner, new tip still the same. I then changed the shroud and it cured the problem.

The shroud should have an insulator around the inside where it slips over the torch, this was worn and had slipped and left an exposed part which was causing the problem.

For the sake of a few quid its worth a go.

  I totally agree with the above, I have the very same welder and had the same problems,  I got mine as a "kit" from e blag i seem to remember it was about £20 ? Came with new liner, tips and shrouds and a few other bits also, Fixed mine a treat,   Also treated it to a new reel of wire as it had not been used for a while and had a coating on it,

[Lucy1978]

this is a very helpful place to ask all welder/welding related questions.

Chris

[BrumLee]

Check the wire feed rollers (the clampy thing) against the wire gauge. Bought a non-working welder, when checked the plank had put 0.4mm wire in whereas the rollers only fed 0.6 and 0.8mm  :roll:  Cheap fix of a roll of new wire  :lol:

[UKJeeper]

(I think) I've fixed it. Took things apart and found that a) the rollers had oil on them, and b) the contacts on the trigger (big brass box in the handle) were quite corroded. Cleaned it all up, and ran a perfect bead across a test piece of metal. Result!

Thanks for all the tips.