Arcing to gun?

[dasiydave]

Hi guys, I'm new on here and have been TIG welding my camper back together but its going rather slow so picked up an ERP 150 and im having problems with it, ive mig'd a lot in the past but never come across this. The arc seems so be arcing back to the tip not through the wire as I think it should so the wire is melting before it gets anywhere near the welding face. I have tried every setting under the sun and was just after some advice?

Cheers
David

 

[Wozzaaah]

Hi David, welcome to the forum.
Is the wire nice and clean?
(No rust whatsoever, not even a light coating)
Is the contact tip the right size and is it a new one?
Does it seem better if you keep the torch lead straighter?

 

[pedrobedro]

Is the shroud clean and have you got the gas on?

 

[dasiydave]

Ive got brand new wire/tip and running pure argon right now cos thats what ive got at the min. The should is a bit tatty but I have cleaned it up. I have fitted a new wire feed unit as the old one was stalling but still havng the issue. could the polarity be **** about face? Am i right in thinking the arc should be between the wire and the face not the tip and the face? cheers David

 

[dasiydave]

just a thought on what pedrobedro said, could the should be live because it is old and a bit tatty, is it worth changing? cheers David

 

[chunkolini]

Spatter down the end of the shroud?

 

[Lewis Medlock]

'Melting before it gets anywhere near the welding face'

Does that mean if you point the torch into fresh air and pull the trigger it still arcs up? If so there's something gone astray in the machine.

If the wire comes out of the torch and hits the work before fusing to the contact tip then it's a wire feed problem.

If it's a wire feed problem check your drive rollers aren't too loose but also check they aren't too tight, this'll deform the wire causing it to jam or judder going through the tip. If the tension's right you should be able to stop the wire feeding when you pinch it with your fingers.

Jim

 

[dasiydave]

it dose arc up between the torch and the face im welding to but I thought the arc should be between the wire coming from the torch and the face not the tip?

 

[Wozzaaah]

You're not being very clear and you haven't answered all my questions.
Are you saying it's arcing between the shroud and the workpiece?
The contact tip transfers the welding voltage to the wire, the arc should be at the end of the wire, nowhere else.
If the shroud is live during welding (test by releasing the wire feed rollers so you don't spew wire out, press the trigger and rub the shroud against an earthed piece of steel or the clamp itself to see if it sparks) then it's shot.
Most likely spatter has got up inside it and bridged the insulation.
You could try cleaning it out but as they cost peanuts it's best to fit a new one, especially as you say it's tatty.

 

[chunkolini]

I can also remember having this problem on my Clarke welder years back.
I had been doing a lot of welding and had cooked the insulation between the shroud and the swan neck. I think the isulation was supplied by a small fibre washer of some kind. Might be worth checking. On higher rated torches the insulation is more robust.
Has your torch got a kind of plastic/rubber pipe over the swan neck? these are found on lower rated torches.
On my 180 amp welder I had to upgrade to a 250 torch as I kept melting the pipe thingy.
Chunko.

 

[KingbearReg]

Hi guys, I'm new on here and have been TIG welding my camper back together but its going rather slow so picked up an ERP 150 and im having problems with it, ive mig'd a lot in the past but never come across this. The arc seems so be arcing back to the tip not through the wire as I think it should so the wire is melting before it gets anywhere near the welding face. I have tried every setting under the sun and was just after some advice?

Cheers
David

Just signed on this forum, Recall the situation, you are having, try changing and checking your wiring. If my memory serves me right, your polarity is set wrong and I am trying to remeber how I changed mine.

 

[Wozzaaah]

Afaik it's not a dual purpose machine so the polarity will be correct.

 

[M0ZOV]

I have the same problem with a Clark welder, I was thinking it was a poor connection between the gun and the wire. I recon that the wire should be live before it gets to the tip and that this happens in the swan neck as mine has a spring in it and I think it is there to help with the connection. I am thinking about buying a new swan neck to see if it cures the fault.

 

[Wozzaaah]

The contact tip transfers the welding voltage to the wire, not the swan neck spring, the clue is in the name.

 

[mike 109444]

I beleive (from what I have seen on 2 different welders) the voltage to the welding wire is feed to it via the feed rollers. If you look at the feed motor it is isolated from the m/c's frame (by insulating washers or similar). Thats why there is the 2 (or 4) thin wires going to the motor and a thick wire that feeds the weld wire via rollers. The tip is copper to stop the molten wire sticking (does not always work!)

 

[shenion]

No the feed rollers need to be isolated as the wire feeds the voltage back from the tip.

The tip electrode is the main point of contact.

 

[Windy Miller]

The contact tip transfers the welding voltage to the wire, not the swan neck spring, the clue is in the name.

No the feed rollers need to be isolated as the wire feeds the voltage back from the tip.

The tip electrode is the main point of contact.

Indeed - otherwise there would be no need for the heavy wires in the cable assembly supplying the torch!

Although in this case it's not actually supplying the torch anymore!

 

[Wozzaaah]

I beleive (from what I have seen on 2 different welders) the voltage to the welding wire is feed to it via the feed rollers. If you look at the feed motor it is isolated from the m/c's frame (by insulating washers or similar). Thats why there is the 2 (or 4) thin wires going to the motor and a thick wire that feeds the weld wire via rollers. The tip is copper to stop the molten wire sticking (does not always work!)

Think about it Mike, that can't be correct as you'd then have a length of wire the full length of the torch lead live which simply wouldn't work.
Also, if you had a birdsnest at the rollers and the wire was already live it could be very nasty.

 

[pedrobedro]

If you apply current to a piece of mig wire at the tip surely the whole of the length of wire will then be live, you can't isolate part of the wire within it's own length which is why the motor and the reel centre are isolated from the chassis. The birdnest inside the machine would only be a problem if it came into contact with the earth cable terminal which is why the earth connection should have a cover over it.

 

[rtbcomp]

Also the case isn't connected to welding earth so it doesn't matter if the live wire touches the case during a birds nest situation.

I reckon the motor will be isolated to stop the case becoming live rather than preventing a short to earth.