Never seen a liner go that bad before. Only thing I can think of is constantly turning the gun around which would be imposable......Mike

 

Well you haven't met the temps we have working for us yet.:laugh:

 

I'm thinking along the lines of twisting the gun up. If that's the case it appears you've got a temp that's not very interested in becoming permanent.

 

The twisting was what I was going to say as well. Looks like a lot of extension cords I have sceen at peoples houses that never take the time to put them away right. Kind of hard to tell from the pic though if it is twisted or just wavy. Also might have had been the wire getting stuck and bunching, but I have never seen wire do that to a liner. Then again I have never used dual shield.

 

I think the drive rolls were to tight and got the wire cork screwing starting into the liner so the linner started cork screwing too.

 

From the looks of it, the wire was under tension while the liner was under compression.

You know what happens when you kink your whip the wrong way or the drive rollers slip for some reason. The wire burns back and it sticks to the tip. Happens to everyone occasionally. If one tried to unscrew and yank the tip out with a pair of pliers while holding the gun without releasing tension on the rollers (or jogging the drive a couple times) that's exactly what a plastic liner might end up looking like.

You can't do it with a *heavy duty* gun like a 400amp Tweco because the liner is a coiled metal housing (like a bicycle or PTO cable housing) and it won't compress at all. I know some of the medium duty guns just use a plastic tube, which is easier to damage if you abuse it.

Extension cords sometimes look the same way some times because non-electrician people tend to stretch the cord to straighten kinks when rolling them up. The stretched outer insulation slides along the inner conductors (which are not as stretchy) and bunches up near the ends where the plugs stop it from sliding along any further.

 

Observe the guy who was working with that welder while he works. Much might be learned from focused and patient observation.

-Mondo

 

My guess would be that the liner somehow carried welding current, which overheated and annealed the liner's wound wire core.

 

OOOhhhh! Good Answer! :laugh:

 

I'm serious. Normally, the liner is electrically isolated; current flow should be from contact tip, to wire, to work.

My guess is that somehow the liner carried high current, which warmed the liner's wound wire wall, causing it to deform.

Burnit should skin back the cover and look for evidence of overheating; such as discoloration of the core.

 

Looks like the last guy that changed it drove it in with a hammer or didn't trim it to length.

OR there is a poor connection some where.

Its sure gonna weld better with a new one.

David

 

My first gut instinct was that you were over working the guns amperage rating. But seeing as you claim otherwise im thinking that who ever changed the liner last wasn't a real sharp operator and ended up just stuffing the liner in there with wreckless abandon at all costs instead of doing what's supposed to be done and trimming to fit.

I have seen PHENOMINAL welders that couldn't change a set of drive rolls so this can happen. Some places like shipyards will fire a welder if they see him doing anything but changing the roll of wire on his feeder. Anything more than that and they have to take it to the tool crib.

 

First thing I see ,,,,,,, many people have found out, installing a new liner, to shorten/lengthen it a half inch, you can twist the gun cable one way or another, just watch the liner recede or come back out. When you do this, obviously, you are simply twisting the liner, either longer or shorter, depending on which way you rotate. Add a little time and heat,,,, you see the result.

 

It does look like it twisted. I don't ever do anything that will keep the liner from spinning at the feed rollers.

As for the liner carrying current... I don't think you will get a teflon liner to carry current sufficient to melt it or even soften it.

If you can tell looking at it that it's a result of heat, you could just get a metal liner.

Word to the wise: Get wire lubricant and one of the felt pieces that lubricates it. At the start of each shift, soak down the felt piece. This cleans the wire and lubricates the liner. It will help improve the life of a liner, and the smoothness of wirefeed.

 

As for the liner carrying current... I don't think you will get a teflon liner to carry current sufficient to melt it or even soften it.If you can tell looking at it that it's a result of heat, you could just get a metal liner.

It is a metal liner, the black stuff just covers the first foot or so. I do think it twisted though.

Well Burnit... What'd the autopsy show?

I cut that black stuff off, neither the metal coil or the insulation showed any sign of heat.
The first shift lead man threw it away though. First shift never cleans up but that thing ended up in the trash. :laugh:

But! It happened again tonight. Same feeder, same lead with the new liner in it. Different operator. I didn't have time time to play around with it but I think I may have a couple possibilities.

1)These guys have really been cranking on the drive roller tension, in one instance he somehow shorted the wire to the tip, fusing them together, then came and got me when it wouldn't feed anymore. The drive roll tension was too high and when I managed to get the wire out of the liner (Vise-Grips) there were two flat spots on the wire from the rollers that had made it into the liner. Its a long shot, but I weigh 240 lbs. and it was hard to pull that wire out, even from the feeder end. The feeder managed to force that in there, maybe that could have done it.

2)The second possibility is that the first liner was too long and was jammed in there, and when I replaced the second liner I didn't do something right because I don't know what the hell I'm doing. :laugh:

Whaddya guys think?

I will pull apart the second liner tommorow.

 

Well Burnit... What'd the autopsy show?

 

Can't see it being too long doing it, you'd never get enough tension on it, at least I don't see how you would. Got me stumped....Mike