Changing liner in a mig gun ? ? ?

[radioman]

I have hobart ez125 and had same problem you did. Two things I know that causes birdnesting for sure. broken liner, or bad tip. I'd replace the tip.

If you cant tell if the liner is broken, since its your first time, I'd pull it out and check it for kinks or separation. This will allow you to understand the workings of how hobart liner connects. I also wonder if the liner slipped out where it goes into the gun. I'd twist off the plastic handle and check and make sure its seated right and o ring is ok.

 

[J_J]

Have you tried blowing the gun / liner out? I like to use the oxygen bottle without gauge. Remove the gun from the welder, remove the contact tip, place the end of the gun that goes in the welder on the opening of the oxygen bottle and crack the valve.
An ear plug works well for a wire wiper too. What ever you do don't buy the wipers with the lube on them!

Now you tell us after I have bought and use them.

Is there a good reason for your statement. I appreciate your advice, so give us the straight story as to why not. I thought the purpose was to clean and lube the wire/liner.

I understand about blowing oxygen through the liner after using the lube. Not good

Excerpts:

A high quality liner can provide a more consistent inside diameter through which the welding wire travels, thereby reducing friction and extending the service life of the liner as well as the time that it takes for wire filings to clog the liner—one of the most frequent sources of liner-related downtime. The liner is most susceptible to this problem when the cable is bent too far and increases the friction between the wire and liner.

Other causes of clogged liners include using an incorrect liner size and trimming it improperly. In both cases, the liner can shave metal filings from the welding wire and become clogged, leading to erratic wire feeding, poor weld quality and birdnests. Because the copper stranding in MIG gun cables is wound in a helix pattern, the cable shrinks when it is twisted. Trimming a new liner to the length of a twisted cable can cause the liner to be too short when the cable is straightened out, leaving an empty space in which the welding wire can become lodged and birdnest.


Additional downtime can be saved by using an easily-replaced partial liner that installs from the front of the gun and only goes through the gun’s neck. The most wire-to-liner friction occurs in the neck, so that part of the liner is usually the first to wear out. Rather than spending 20 minutes replacing the entire liner when only that portion becomes worn, some companies offer partial liners that can be changed in as little as two minutes.

http://www.bernardwelds.com/articles/article31.htm

 

[IslandTractor]

I'm confused by you guys who are using regular MIG setups to run aluminum wire. I though spool guns were necessary to run aluminum as it is too soft and pliable to be "pushed" from the machine to the regular gun tip. That is why spool guns were invented so there was less distance to push the aluminum wire. No?

I'd also second JJ's question: what is bad about the felt pads and lubricant for a mig? I admit to having bought a pack and lubricant but have never installed it. My thought was that some of my big rolls of flux core were showing some rust on the surface and that the cleaner/lubricant would be insurance that the wire would feed through the liner more easily.

 

[Shield Arc]

Now you tell us after I have bought and use them.

Is there a good reason for for your statement. I appreciate your advice, so give us the straight story as to why not. I thought the purpose was to clean and lube the wire/liner.

Majority of my welding experience has been with Lincoln's Innershield wire, and LN-22s and LN-25s which both have serrated drive rolls, which eat the wire up. Lincoln's Innershield wire comes with a graphite lube on it. What a mess the wire shavings and graphite lube makes in the Lincoln Innershield guns! We use to blow all the guns out every Friday night before going home, now a days a K-126 gun is over $300.00 and you can't replace the liner in them! After a life time of putting up with the lube on Innershield wire, I refuse to deliberately lube a wire!
Few years ago this very subject came up on the Miller welding forum, one of Miller's moderators stepped in and said he also doesn't recommend lubed pads, dry pads or an ear plug yes.

 

[J_J]

Is it just Lincoln Innershield wire, or others ?

 

[Shield Arc]

Been so long I had to go back out to the shop to make sure.:laughing:
Hobart's Fabshield 21-B has a lube, but not near as heavy as Lincoln's wire.

 

[J_J]

Do you always use name brand wire, and is there a really big difference?

 

[Shield Arc]

You know, I never really thought about it! But looking at that cabinet of wire I guess I do. Few days ago I went to the welding supply, asked for a roll of Lincoln .045 L-56 wire, (love that stuff). They no longer carry Lincoln! Sold me a roll of some wire, but I can't remember the name. Just went out to look, no name on the box, so it must be a no name brand:laughing:. Haven't tried it yet, but the salesman, (known him for 25-years) says everyone likes it better than the L-56.:confused3:

 

[Hooked_on_HP]

I'm confused by you guys who are using regular MIG setups to run aluminum wire. I though spool guns were necessary to run aluminum as it is too soft and pliable to be "pushed" from the machine to the regular gun tip. That is why spool guns were invented so there was less distance to push the aluminum wire. No? .

You can run aluminum through your mig. You have to run the stiffer 5356 wire and not the 4043. The thicker the wire the easier it is to feed. You need to keep the cable of the mig gun pretty strait,and you don't want a lot of tension on the rollers or it will egg shape the wire. Spool guns are much easier and you can run the softer wire. You also need 100% argon.
Bill

 

[dstig1]

Have you tried blowing the gun / liner out? I like to use the oxygen bottle without gauge. Remove the gun from the welder, remove the contact tip, place the end of the gun that goes in the welder on the opening of the oxygen bottle and crack the valve.
An ear plug works well for a wire wiper too. What ever you do don't buy the wipers with the lube on them!

Seriously? Blowing out with oxygen? That is rather dangerous....compressed air is not that hard to find...

Yes I know you've done it a million times, but there are very good reasons the oxygen gages say "use no oil", for example. The reasons start with KA and end in BOOM. Pure Oxygen and any organics are a very explosive mixture.