Teflon liner MIG gun questions

[Beerhippie]

I've used my old Millermatic 120 w/brand new gun and cable for some light stainless welding in the past, and had horrible problems with wire feed using .030 ER 308 wire. If the cable wasn't perfectly straight, I'd get a bird's nest in the case--and often enough when the cable was perfectly straight. This wasted a lot od expensive SS wire.

I just received a new Teflon liner for it, and have a question or two:

Can I use the Teflon liner with regular steel wire or do I need to change it out for the steel liner every time I go from one to the other?

Anything else I should be aware of?

I realize that swapping liners isn't a big deal and I won't be using SS wire all that often--I think.

I've gotta go order a can of Tri-mix now.... Then burn some wire in prep for some SS tank jacket repairs.

 

[imagineer]

I doubt the problem is the liner. Try using a larger diameter electrode tip, or drilling out the existing one.

FWIW, to avoid feed problems using my spool gun with .035" 5356 wire, I'll drill out the electrode with a #57 (.043") or #56 (.047") drill.

 

[Beerhippie]

I doubt the problem is the liner. Try using a larger diameter electrode tip, or drilling out the existing one.

FWIW, to avoid feed problems using my spool gun with .035" 5356 wire, I'll drill out the electrode with a #57 (.043") or #56 (.047") drill.

You drill it out oversize for the wire you're using? I'm using .030 wire with a tip sized for it.

I sometimes wish I had a spool gun... but can't see spending more for one than the welder is worth.

 

[imagineer]

You drill it out oversize for the wire you're using? I'm using .030 wire with a tip sized for it.

I sometimes wish I had a spool gun... but can't see spending more for one than the welder is worth.

Yes, I regularly drill out welding tips (or at least use a tip size larger than the wire). Probably because I buy cheap wire...I find that it's not always round and sometimes is larger than the stated diameter. This is especially true for aluminum.

I hold the drill bits using a pin vise, then chuck the electrode tip in a cordless drill, and go slow.

I have a Lincoln 100SG spool gun that I use for aluminum welding. It's finicky.

 

[Beerhippie]

Here's the liner:



My hose is only 10' long, so I'm hoping that will work, but I'll keep the tip orifice in mind if it doesn't.

Back to the original question: Can I use the Teflon liner with regular steel (E70S-6) wire or will it cause premature wear of the liner?

 

[Steve from Socal]

The liner 'should' be OK mig wire is coated so the abrasion is not a big deal.

Regarding the SS wire, are the rollers correct for that wire?

 

[Beerhippie]

The liner 'should' be OK mig wire is coated so the abrasion is not a big deal.

Regarding the SS wire, are the rollers correct for that wire?

I have the proper drivers for it.

Tri-mix gas should be here Thursday and I can start burning some wire to see how comfortable I feel welding on a $40K fermenter with it.

I probably should pick up one of those drum-type surface finishing tools from HF before they're gone--if I'm not too late already.

 

[Beerhippie]

Well, I may have found the problem:





The liner and stinger are a few months old. I suspect that that break was there when I got them. It's not real clear, but the busted off end in the stinger is slightly rusty at the break.

 

[Torque&Recoil]

Here's the liner:



My hose is only 10' long, so I'm hoping that will work, but I'll keep the tip orifice in mind if it doesn't.

Back to the original question: Can I use the Teflon liner with regular steel (E70S-6) wire or will it cause premature wear of the liner?

I am not a professional welder, but my first Mig was an inexpensive Century which didn't feed worth s*** until I put in a teflon liner. I only ran steel wire in that machine and the teflon made all the difference. That machine was just for hobby use, and the liner never wore out. Just leave your liner in and enjoy the improved welds.

 

[Beerhippie]

This project has officially become a "fifteen-minute-job". I bought the liner to fit the Millermatic, but had replaced the stinger with one from our welding and gas supplier, OXARC. Of course, it was not a Miller product and I don't know just what it is--branded OXARC--but the fittings from the Miller liner didn't fit. I had to remove the fittings from the old, broken liner, drill then out about 1/64" to fit the Teflon, then reassemble the stuff to work. To get the liner to feed all the way through the gun, I had to pull it back out and carefully chamfer the end of the liner with my pocket knife. Good thing I sharpened my knife a couple of days ago.

Now, I can't get the wire to feed all the way through the liner. It feels like it hits the bend of the gun, then just comes to a dead stop. I think the sharp cut end of the wire is gouging into the bend in the liner. I may have to take the gun apart (again) and straighten the liner to get the wire through. I just hope I don't have to do this every time I change wire. I even tried using a bypass cutter to prevent getting the chisel tip that a pair of dikes leaves--again, no joy.

In the YT videos, it takes five minutes to do this job.

 

[Beerhippie]

According to Weld.com, I will need to swap out the liner for steel wire as the Teflon will wear quickly at bends--like the 45 on the gun. Seems that's also why I had trouble feeding the steel wire--it's too stiff and just digs into the soft Teflon liner on that same bend.

I have a new steel liner--under warranty--coming from Oxarc. Should be here today. I'll try it out with the stainless wire and see if not having a break in the liner makes any difference.

 

[no704]

Not really sure on mig but with tig folks seem to be really **** about cross contamination for different materials.

 

[Beerhippie]

Well, the Oxarc guy showed up with my new liner today... for the wrong stinger. While showing him what I thought were the "broken" pieces of the old liner, I noticed that the OD of the two pieces were different! The short--1" or so--bit that I thought had broken off is larger in OD than the rest of the liner.

I asked if we can just replace the entire stinger with a proper Miller one--on warranty as the odd-ball stinger I bought from them doesn't seem to be retro-fittable with any known liner. The stinger they sent me the last time doesn't have any markings but OXARC, and even the Oxarc guy had never seen one like it.

 

[Beerhippie]

Not really sure on mig but with tig folks seem to be really **** about cross contamination for different materials.

Good point there. I don't know how much contamination the wire would pick up and haven't seen or read any warnings about it, but something to keep in mind.

Fortunately, the welds I need to make on the fermenter are all on the outside of the tank, so contamination is a bit less of a concern. I always passivate SS welds after grinding and blending, which helps prevent rust spots.

 

[Jacko264]

I was always told Teflon liner for aluminium and metal liner for steel / s/ steel and that’s what I have always done .
its a good tip about drilling out the tips or fit next size up
I have been welding for about 50 years and it’s never let me down
ps use anti splatter spray on the tips it helps and helps the shrouds from clogging
Graham

 

[Beerhippie]

I was always told Teflon liner for aluminium and metal liner for steel / s/ steel and that’s what I have always done .
its a good tip about drilling out the tips or fit next size up
I have been welding for about 50 years and it’s never let me down
ps use anti splatter spray on the tips it helps and helps the shrouds from clogging
Graham

A former boss taught me to use silicone spray for the shroud to keep it from clogging. Works quite well!

 

[toplessHO]

A former boss taught me to use silicone spray for the shroud to keep it from clogging. Works quite well!

I use tip dip
Pam works for protecting finished work from BB damage. Just mask welding areas

 

[Beerhippie]

I use tip dip
Pam works for protecting finished work from BB damage. Just mask welding areas

I haven't used my tip dip since learning the silicone trick. Just tap the shroud on your workpiece occasionally and all the crud falls right out.

I do need to get some spatter spray for my various welding surfaces--especially the parts of my bench that I covered in stainless. Weld spatter sticks to stainless like nothing else!

 

[BigMike782]

Well, I may have found the problem:





The liner and stinger are a few months old. I suspect that that break was there when I got them. It's not real clear, but the busted off end in the stinger is slightly rusty at the break.

I'm confused as to what is broken.

Typically when switching from carbon steel to stainless it's best practice to change the liner to a common steel liner to avoid picking up any contaminates from the carbon steel.

 

[dr_clyde]

I have never needed to use a teflon liner for any steel or stainless wire.

Teflon liners are intended for aluminum or other really soft, hard to feed wire. Stainless should feed easily in a regular liner. And even then, teflon liners are really just a stop-gap or occasional fix for aluminum, a spool gun or push-pull setup is the recommended way to feed aluminum wire.

That isn't to say you can't use one, but I have never heard it necessary. If you're passivating the welds, you shouldn't need to worry about contamination from the old liner either. The passivation process removes any free iron and allows the chromium carbides to reform the passive layer. If it's really dirty or old, it wouldn't hurt to switch it out but it's not necessary for each time you swap wire types.

You also should just buy the correct tips for your wire size. Drilling them out will just increase the odds of arcing inside the tip causing feed issues and shorts in the tip. Stainless is a bit more aggressive in wearing tips, why help wear out things?

I worked as a process fabricator in a large brewery for a number of years, and we never used a MIG for anything stainless, especially not in the cellar. I personally wouldn't want to make welds on a fermenter with a MIG welder unless I had a setup that was very well dialed in and sized for the job. I would much prefer stick welding for any sort of structural stainless, but that's just me. We made every attempt to TIG as much as possible as the welds were so much easier to clean and avoided spatter or any sort of visual defects.

 

[Beerhippie]

I have never needed to use a teflon liner for any steel or stainless wire.

Teflon liners are intended for aluminum or other really soft, hard to feed wire. Stainless should feed easily in a regular liner. And even then, teflon liners are really just a stop-gap or occasional fix for aluminum, a spool gun or push-pull setup is the recommended way to feed aluminum wire.

That isn't to say you can't use one, but I have never heard it necessary. If you're passivating the welds, you shouldn't need to worry about contamination from the old liner either. The passivation process removes any free iron and allows the chromium carbides to reform the passive layer. If it's really dirty or old, it wouldn't hurt to switch it out but it's not necessary for each time you swap wire types.

You also should just buy the correct tips for your wire size. Drilling them out will just increase the odds of arcing inside the tip causing feed issues and shorts in the tip. Stainless is a bit more aggressive in wearing tips, why help wear out things?

I worked as a process fabricator in a large brewery for a number of years, and we never used a MIG for anything stainless, especially not in the cellar. I personally wouldn't want to make welds on a fermenter with a MIG welder unless I had a setup that was very well dialed in and sized for the job. I would much prefer stick welding for any sort of structural stainless, but that's just me. We made every attempt to TIG as much as possible as the welds were so much easier to clean and avoided spatter or any sort of visual defects.

All I'll be using the MIG for on the fermenter is the outer jacket, as my TIG skills aren't up to filling the gap where I'll have to cut the jacket off to access the leaking glycol jacket under the outer jacket and insulation. I use TIG for anything sanitary, and we pretty much don't have any structural stainless that I ever have to work on.

When possible, we hire a real, certified sanitary and pressure-vessel guy to do any work on the fermenters and bright tanks. Unfortunately, there does not appear to be any such welders this side of the state. Our usual guy has family in the county, so when possible we make a list of projects for him to do when he's out here about twice a years.

I just pick up the slack and "gotta get done now" work.

 

[T444e]

When possible, we hire a real, certified sanitary and pressure-vessel guy to do any work on the fermenters and bright tanks.

What's the fun in that. Just hire the cheapest "weldor" for the repair. This way the next guy making the repair, that is certified and has an 'R' stamp, along with his AI, sees the unstamped repair and start asking questions you don't want asked.

Good for you doing it the right way.

 

[Beerhippie]

What's the fun in that. Just hire the cheapest "weldor" for the repair. This way the next guy making the repair, that is certified and has an 'R' stamp, along with his AI, sees the unstamped repair and start asking questions you don't want asked.

Good for you doing it the right way.

I'm the guy who has to, literally, polish that ape's turds.... Been there, done that. "Back gas? What's that?"

 

[T444e]

Just polish the turd. I've been there with our weldor, inspector and our AI. Our AI was asking why we did a repair on a pressure vessel with an unstamped repair, unfortunately it was a project I inherited. He did not want to sign off on our repair but eventually did with very detailed documentation of our repair and a detailed note of the unstamped repair. The gist of it was do not repair a pressure vessel with an unstamped repair.