[cboy]

I've recently developed a porosity problem with my Miller 175 which persists no matter what flow rate I use or how vigorously I clean the workpiece (I've tried nearly every setting from from 7 to 25 CFH). So today I started pulling things apart to see if I could find the culprit.

When I pulled the liner out I discovered this "separation" in the plastic housing around the liner coil (see first two photos below). This break appears to be totally uniform as if two pieces of plastic were used originally. There is some wear on both sides of the split, but I can't quite imagine a scenario which would cause a separation like this.

The other thing that makes me doubt this is the problem is that another foot or so up the liner (towards the gun), the plastic coating is eliminated altogether (see final photo). This makes me think the plastic is not there to eliminate loss of gas but rather as protection of the coil.

But then I know very little about what goes on inside the welder. So maybe one of you more knowledgeable welders can tell me if this might be the problem or if a separation like this is pretty standard.

[cboy]

I think I've answered my own question here but just wanted to pass it along. HERE is the culprit. The brass nozzle had entirely separated from the hose at the wire feed end of the whip. Also, the copper wire has almost all frayed away so there is no support left at the joint.

Looks like time to order up a new gun/whip.

[cboy]

I guess I still do have a question. Has anyone successfully repaired a hose in this condition? Can this copper "nut" (arrow) be removed so that the copper wire can be re-attached to the brass connector?

I made one attempt at getting it off but don't want to totally strip it if there is some secret to removing and reusing it.

[oldred]

Well you certainly found the problem but unfortunately it's not an easy fix, not with most guns anyway. That "nut" is actually a crimped ferrel (did I spell that right? ) that is put on with a hydraulic crimping tool and it's difficult to replace with tools commonly found in the shop.



Although you have found the problem in this case another common, but sometimes difficult to identify, cause of the symptoms you describe is a loosely fitting nozzle that otherwise might appear ok. What happens is that if the nozzle fits loosely or the seal it fits over is damaged then air will be siphoned into the shielding gas stream and will cause porosity so make sure the nozzle seals tightly at the back.

[cboy]

Originally Posted by oldred

Well you certainly found the problem but unfortunately it's not an easy fix, not with most guns anyway. That "nut" is actually a crimped ferrel

What, exactly, is the purpose of the copper wire at this junction? If it's only purpose is to support the connection from side-to-side and in-out movement, I'm wondering if I can just solder the wire to the outside of the ferrel?

And thanks for you info oldred. Not what I had hoped to hear but good to know.

[jonahb]

That's the second time I have ever seen a whip come apart like that. The last one I seen exactly like that(where the wire comes off the ferrel) is when another welder was pulling the gun to bring the welder closer to where he worked and had the same problem no gas an the trigger work only half the time. Did your whip act funny besides the lack of shielding gas?

[SuthnCustoms]

I'd vote to just buy a whole M-100 gun for it.

I've ran miles of wirefeeds on jobs and have seen personaly when trying to "tinker" or rig up a repair on them only leads to frustrations and/or anger when the results end up less than satisfying.
Especialy if your in the middle of a project and the temporary fix comes apart on it again.

Replacing old worn out guns/liners with new on those MIG machines can make it feel like a brand new machine once again.

they sell the Miller setups for them here 130.00ish

http://store.cyberweld.com/m10miggun.html

HTP(USAWELD.com) sells replacements for the Miller 175's for a lil less money and they also sell other parts for it too.and HTP has been a VERY reputable company that is not in the big "media circus" like the big 3(Lincoln,Miller,Hobart)
http://www.usaweld.com/Miller-M10-MI...-m10-parts.htm

You may even be able to find someone who sells just the hose from the machine to the gun and keep your old gun and be on the cheaper side..dunno though since i've never tried that route.

[oldred]

I have to agree it's best to just replace it because repairs are usually less than satisfactory. We kept replacement assemblies at the shop (these were all much larger Bernard and Tweco guns but the design is pretty much the same) and when one went bad it was just tossed. I have seen guys retrieve the old gun and attempt to repair them but rarely was one worth the effort. That hose, clamp, wire and crimped ferrel is a very compact assembly and getting it all back together in such a manner that it will fit back inside the sheath is just about impossible without the special tools that the factory uses.

[cboy]

Originally Posted by jonahb

Did your whip act funny besides the lack of shielding gas?

Nothing that I can recall. But then I was also making a lot of adjustments (heat, wire speed etc.) to try to deal with the porosity issue, so I really can't say for sure.

Also, I don't drag my welder around by the whip...or at least not intentionally, so I'm a bit perplexed as to how the wire strands started breaking as they did. If you look closely at the picture you can see that the strands are broken off quite uniformly, almost as if a wire cutter was used to snip them straight. If it were wear over time, I would expect the strands to be broken at very random lengths.

Anyhow, thanks to all for your rapid responses and good advice on this. I have ordered up a new gun assembly. I might try to cobble things together tomorrow with the old one to keep going until the replacement arrives.

[oldred]

That type of failure is not uncommon nor is it your fault, in normal usage the gun will be at all sorts of angles and the lead will naturally tend to flex at that point which will fatigue the wires all in the same spot. What that shows is that you have been using your welder for it's intended purpose and not just as a shop decoration! Actually a gun assembly is a replaceable item with a limited life-span and there are several brands that could be a direct replacement for your welder, it mostly depends on the attachment fitting at the roller assembly. While pulling on the gun to move the welder, or for any other purpose, is not a good idea it should not cause that kind of damage unless it is already fatigued or someone yanks on it awfully hard but, like jonahb, I have seen that done!

[jonahb]

Originally Posted by cboy

Also, I don't drag my welder around by the whip...or at least not intentionally

I didn't mean you drag your welder intentionally and good luck with the new replacement. I remember one time at work, I was welding on points to some driving piles for a wharf. It was on a rotary so all I had to do is pull the trigger and weld it on a flat or vertical. I tacked one side then rolled it a 1/4 turn and tacked it again, then rolled it another 1/4 turn. Then all of a sudden the point fell off and landed right on top of the whip. Those points are about 125lbs and there was no mercy on that whip. The whip was cut in two while the mig was having a head-fit because the wire were shorting out and it tried to weld, push wire and flow gas without the 4 remaining feet of whip. So lets say I got my fat butt over there in about two second to shut off the mig. Believe me I still hear it to this day and it was about 2 years ago.