Do all you MIG welders who actually know what you are doing change gun liners when you change wire size?

I bought this old Hobart Handler way back in the 80s and for decades, I ran wire wire from .023 solid to .045 flux core through the same liner that was in the gun when I bought it. I didn't notice any issues. That liner finally went bad and only in searching part numbers for replacement did I realize there are different sizes. So I bought two liners. One that is good for .024 - .030, and another for .035 to .045. When I pull this spool of .035 off to switch back to .023, should I also swap out the liner? Or is it more a case that a liner can be too small for a wire size, but being a little too large isn't a problem?

I won't claim I know what I'm doing but I've never changed the liner, nor had any issues swapping between .030 and .023 in my Miller 211. All I do is flip the drive wheel to account for the wire size - and it accommodates both so I assume the liner is OK with either size...
But sorry, I can't help you with the .023 to .045 range question. I've never needed more than .030 for what I've done.

Liners last a long time.. The only needed change is the tip and drive rolls for wire size change.. Liners will wear over time or if they have been kinked.. Best thing to do to prevent that is a wire cleaner/lube setup.. Won't help with the kinking though thats just a common sense thing..

Liners would require changing if you go from steel to aluminum as that typically will be teflon..

And by the looks of things the 3 of us have been shooting the most wire collectively lately.

And No unless you are going from flux core to aluminim and your MIG gun has a drive head in it. If so, usually the liner from the drive head to the tip is changed to a teflon liner....that is if you have a gun with a drive head.

Thanks guys!

That's kind of what I thought. Bad news is that I probably wasted money on this smaller liner, but since 99% of my welding is in the .023-.030 range, it will make a good backup. I think maybe the only difference is the diameter of the hole in the collet.

That cheap POS liner that came with my welder only lasted 30 years. I just ran it through the felt cleaner pad that came with the welder, but I'm going to try to pick up some new pads and cleaner fluid when I'm in town tomorrow.

Also, I only have two rollers. One flips from .024 to .030, the other from .030 to .045. Don't have one specifically for .035 but this spool of .035 I have seems to run through the .030 groove just fine. I can't imagine there is a problem with that.

The wrong drive roll for the wire will crush the wire and cause for bird nesting and additional wear on the contact tips as they are round and the wire no longer will be.

Ah what do I know been welding for 27 years and taught it for 20

Feel free to call or email if you need any insight... I do this stuff everyday and always willing to help..

But is the difference between .030 and .035 enough to be a problem? My manual doesn't even list a part # for a .035 roller so I'm not sure what to order. I think this is the roller, but I don't think it is any different from the one I have. Looks to me that .030 and .035 roller is the same groove.

Sounds like you might want to email or call mb911.

Well, I think I have much bigger problems. Replacing the liner didn't fix the symptoms I was hoping it would, and I think the welder is dying. My welder has been getting progressively weaker during this project and I've been in denial. Since I've been welding entirely 18 and 21 gauge sheet, I've been able to get good welds by cranking up the amperage. I didn't realize how bad it had gotten until I stopped to think that I've been welding 18g at the highest setting which should have been blowing out like crazy. Loading the .035 wire made me finally wake up to what is happening. I can barely strike an arc with the thicker wire. Instead, it just spits out a rat's nest of semi-molten wire. Did some googling and what I'm seeing sounds a lot like bad diodes in the bridge rectifier. I'll do a bit more digging to see if it is something I can fix inexpensively. I'm not sure how much more $ I want to sink into this fossil of a welder that was at the low end, even when new.

I’m no expert by far, but the roller is there to feed the wire, a wire too small will get lost in a larger groove, causing feed problems. Wire too large the groove may pinch, or cause excess pressure on the wire, causing feed problems.

The roller should be able to handle a small range of wire size...

More info is better, check your ground cable.

Thanks, did that. It's looking more like one or both diodes have gone bad. I'll test them tomorrow to make sure. But that seems to be a common failure item causing low output or blown breakers (which it did twice just before it went weak). Hoping that's what it is because they'll be fairly easy to replace and won't break the bank.

Yes, sounded like you had worse issues but I was hoping the best for you.

Something to be said about a box you know and like, would be worth spending a little to get it running right... some of the newer boxes are certainly made with lesser materials than your 80s box.

Hobarts handlers are a great product.. You should be able to test and replace easily.. And yes roller and wire have to match.. .035IMHO is too big for the handlers..

I changed liners the first time when I tried to weld with aluminum wire. I dont anticipate changing it for another 10 years..

I would only change the liner if for some reason the cord got kinked or if you feel like there is a problem with consistent wire feed.

Both diodes test open in both directions. Local welding shop sells Miller (it's a Miller part) but had no interest in finding diodes for me. But they are easy enough to order online. It just means no welder for the weekend.

Ben, I don't normally run .035, but the last time I tried to get .030, the shop was out and I had some 3/16" steel I needed to weld ASAP, so I bought this spool. It seemed to weld fine before the diode issue. But it isn't a size I normally use (except for occasional flux core).

Yes Hobart is owned by Miller. Too bad they were not willing to help..

The trick for welding thicker material is to preheat with an oxy/act setup.. That way it will be preheated though deposition rates are lower it will be sound weld and will require you to do multipass..

And here I was just commiserating with my neighber an hour ago about how nice it would be to have and oxy/acet. Out of curiosity, why not just weld with the gas for thicker material if you have it available?

Oxy/act is very very slow process. Preheat is really all its good for these days though a very good welding process for strength and ability to visually inspect for quality