Best gas for mig Welding sheet metal?

Susquatch

Ultra Member
Premium Member
Horrible welder here. My very best is probably way worse than your very worst. But sometimes I need to try.

I'm trying to repair a UTV. The gussets are just bent sheet metal that are torn.

I've always used shielded wire. But that isn't working on this job. It's just blowing through no matter what I do. I think I need a TIG welder or try to use some 025 solid core wire with shielding gas. Another new welder was vetoed by the CFO. Something silly like you don't even know how to use the stuff you have properly, you don't need another one to add to the confusion. So gas and solid wire it's gunna have to be.

Problem is that I dont know where to begin.

What gas is best (100% CO2 or 75/25 CO2/Argon?

My EasyMig 180 welder came with a pressure gauge and fittings. But will I need any special adapters or a flow gauge? Any and all advice is appreciated.
 

David_R8

Scrapper of metal
Premium Member
It should all connect up just fine.
It would be worth your time to get some stock of similar thickness and test various wire speeds and voltages to find what is going to work best.
 
I run the mix gas on mine. Your regulator setup will work fine, it's what I use, but I believe a flow gage would less wasteful, as I error the the heavy side with the gas. Once you go to gas, I doubt that you will go back to the flux core very often unless outside in the wind. The shielding gas doesn't do well in wind so indoors or calm days are best. Run short beads to keep heat buildup to a minimum, and practice on some scrap of equivalent size to get a good feel for it. Purposely try and see how much it takes to burn through and then adjust settings etc.
 
... also, try and set your test pieces up in the same angle etc that your workpiece will be in, because there's a world of difference between a piece laying flat on the table and you laying flat on your back trying to gain access with the gun.
And metal prep is important to insure good clean penetration... And, above all, enjoy your project and all the ones that this opens the door to.
 

Susquatch

Ultra Member
Premium Member
It should all connect up just fine.
It would be worth your time to get some stock of similar thickness and test various wire speeds and voltages to find what is going to work best.

practice on some scrap of equivalent size to get a good feel for it. Purposely try and see how much it takes to burn through and then adjust settings etc.

You guys are giving me way to much credit. Practice isn't gunna do anything for me except delay the onslaught of disappointment. I do ok with heavy farm equipment, but even that isn't pretty.

Try and find when it blows through? Ya, that happens the moment I strike an arc.

At my age, the biggest challenges are my eyesight, my arthritis, and the shaking in my hands.

But I will try, and yes - I will have fun regardless!
 

David_R8

Scrapper of metal
Premium Member
You will need small diameter wire, dial down the voltage and wire speed.
Despite MIG being sometime seen as the hot glue gun of welding it takes practice to get it right.
 

John Conroy

member
Premium Member
On thin sheet metal I usually "stitch weld" to avoid burn through but still get good penetration. Roughly 1 second on time and 2 second off time but do test welds to verify what works without burn through. Some of the new welders have auto settings for this but I make due with the manual old school method.
 

CalgaryPT

Ultra Member
Vendor
Premium Member
Horrible welder here. My very best is probably way worse than your very worst. But sometimes I need to try.

I'm trying to repair a UTV. The gussets are just bent sheet metal that are torn.

I've always used shielded wire. But that isn't working on this job. It's just blowing through no matter what I do. I think I need a TIG welder or try to use some 025 solid core wire with shielding gas. Another new welder was vetoed by the CFO. Something silly like you don't even know how to use the stuff you have properly, you don't need another one to add to the confusion. So gas and solid wire it's gunna have to be.

Problem is that I dont know where to begin.

What gas is best (100% CO2 or 75/25 CO2/Argon?

My EasyMig 180 welder came with a pressure gauge and fittings. But will I need any special adapters or a flow gauge? Any and all advice is appreciated.
The 180 is a great machine for sheet metal. It's a little deceiving because it looks like the settings are detents, but in fact they are continuously adjustable, which is what you want. The ability to fine tune voltage and wire speed is critical. The inside of the machine will have a chart which is usually darn close to what you will find works well. You will see a huge improvement when you go to gas (75/25 is a great choice for steel as @David_R8 says). It's important to match the settings to the gauge you are using, but your machine can do down to 24 gauge.

Flux coated wire like you have been using, or stick for that matter, is a pain to do sheet metal with. The main reason is that the welding pool gets hidden by the flux, so by the time you realize you are about to blow through, it's too late. If you've ever tried welding sheet metal with stick and a buzzbox, you know what I mean. If you think you are a bad weldor, and all you ever do is flux core on thin gauge metal, there's your problem.

MIG is only a mystery until someone spends an hour with you showing you how to do it right...especially with sheet metal. If you were closer I'd say buy a couple coffees, come over to my shop and I'll guarantee you leave with confidence in an hour. It really makes a world of difference with sheet metal if someone shows you the tricks. If you can find someone close to you who can show you how, your problems will be solved. You don't need TIG for sheet metal; you just need the right settings and a lesson—like all of us do. Most auto body shops don't use TIG for panels; they use MIG, and that says a lot. Your machine can work fine, with a few operator tricks.

The biggest mistakes with sheet metal welding are gap and heat. Flux core is way harder to do on thin metal. But with gas you should easily be able to weld down to 20 gauge (thinner with practice). Gap has to be tight between metal in order to bridge it quickly. If it is too large, by the time you develop enough puddle to bridge the gap, you've blown through the metal. This occurs in fractions of a second. You can buy sheet metal devices cheaply to aid in the issue (https://www.princessauto.com/en/4-pc-butt-welding-clamp-set/product/PA0008393878) but they aren't necessary. And as David says, thin wire is best. When I do 24 gauge, I swap out rollers and use .023 wire in my big machine. But you should be able to do 20 or even 22 gauge with .035 after some practice.

As you probably know, stitch weld only, until the gaps are well spaced and filled. When they teach on sheet metal they teach to tack weld small dots only. Then, as you get a feel for how much heat is too much, you lengthen the tacks. Soon you learn how long a weld you can do before the heat can't escape and it blows through. On 20 gauge it's about 3/8". The ends of the pieces being welded are the toughest because the heat has nowhere to go, and it blows through. Smaller tacks, or using a heatsink helps. If the speed thing frustrates you, keep a wet cloth nearby and cool the weld down immediately. That will speed up the project and help prevent warping. BTW if the speed thing does annoy you, don't ever buy a TIG because it is even slower.

One last tip—if you are using magnets to hold your pieces together (as many people do), stop doing this. In thin sheet it plays havoc when welding within close range. Either rig something different, or use the clamp set I referenced above. You will see a difference.

If you are still frustrated after converting to gas, post some pics of your project/coupons and I'm sure we can walk you through set up and welding online. Lots of great videos on YouTube, but if you can't find one that is a close match to your problem, I'm happy to replicate it as best as I can in my shop and do a video for you.
 
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Susquatch

Ultra Member
Premium Member
You will need small diameter wire, dial down the voltage and wire speed.
Despite MIG being sometime seen as the hot glue gun of welding it takes practice to get it right.

Bought some gas and some 025 wire this afternoon. Gunna give it another shot tomorrow.... Thanks David!

Don't forget what I said earlier. I'll probably get worse from age faster than I can ever get better with practice........ LOL!
On thin sheet metal I usually "stitch weld" to avoid burn through but still get good penetration. Roughly 1 second on time and 2 second off time but do test welds to verify what works without burn through. Some of the new welders have auto settings for this but I make due with the manual old school method.

This is a great suggestion that I've never heard before. I like it cuz it makes sense!

Thanks John!
 

Susquatch

Ultra Member
Premium Member
The 180 is a great machine for sheet metal. It's a little deceiving because it looks like the settings are detents, but in fact they are continuously adjustable, which is what you want. The ability to fine tune voltage and wire speed is critical. The inside of the machine will have a chart which is usually darn close to what you will find works well. You will see a huge improvement when you go to gas (75/25 is a great choice for steel as @David_R8 says). It's important to match the settings to the gauge you are using, but your machine can do down to 24 gauge.

Wow! Someone else who writes as much as I do!

Sounds to me like you LOVE welding! Maybe I will too someday!

If only I did live closer to all you western guys. That would be sooooo cool!

OK, so I bought some 75/25 gas and some 025 S-6 mig wire this afternoon. Gunna give it another try tomorrow. Lots of great suggestions.

I didn't know that the dials were continuous! After looking at it just now, the feed rate even feels continuous, but the voltage has detents and won't go below A. I'll have to see if I can measure it to confirm that it actually is continuous. But regardless, I had everything on the lowest settings so I don't think that will help. But gas might! It would be great to go to 24gauge, but I'll be happy at 16.

Flux coated wire like you have been using, or stick for that matter, is a pain to do sheet metal with. The main reason is that the welding pool gets hidden by the flux, so by the time you realize you are about to blow through, it's too late. If you've ever tried welding sheet metal with stick and a buzzbox, you know what I mean. If you think you are a bad weldor, and all you ever do is flux core on thin gauge metal, there's your problem.

I don't think hiding the weld pool will matter much for me. I can't see anyway.

I've done lots of stick Welding and flux core mig on heavy metal. I've even done aluminium in the past. But I've never ever laid a bead I could be proud of.

MIG is only a mystery until someone spends an hour with you showing you how to do it right...especially with sheet metal. If you were closer I'd say buy a couple coffees, come over to my shop and I'll guarantee you leave with confidence in an hour. It really makes a world of difference with sheet metal if someone shows you the tricks. If you can find someone close to you who can show you how, your problems will be solved. You don't need TIG for sheet metal; you just need the right settings and a lesson—like all of us do. Most auto body shops don't use TIG for panels; they use MIG, and that says a lot. Your machine can work

So, a body shop guy toward Windsor fixed my wife's jeep recently. In casual conversation, he offered to help me get started with mig. I plan to take him up on that.
The biggest mistakes with sheet metal welding are gap and heat. Flux core is way harder to do on thin metal. But with gas you should easily be able to weld down to 20 gauge (thinner with practice). Gap has to be tight between metal in order to bridge it quickly. If it is too large, by the time you develop enough puddle to bridge the gap, you've blown through the metal. This occurs in fractions of a second. You can buy sheet metal devices cheaply to aid in the issue (https://www.princessauto.com/en/4-pc-butt-welding-clamp-set/product/PA0008393878) but they aren't necessary. And as David says, thin wire is best. When I do 24 gauge, I swap out rollers and use .023 wire in my big machine. But you should be able to do 20 or even 22 gauge with .035 after some practice.

Those PA Clamps look like they are designed to create a gap. Are they supposed to yield a gap? What if I am overlapping?

As you probably know, stitch weld only, until the gaps are well spaced and filled. When they teach on sheet metal they teach to tack weld small dots only. Then, as you get a feel for how much heat is too much, you lengthen the tacks. Soon you learn how long a weld you can do before the heat can't escape and it blows through. On 20 gauge it's about 3/8". The ends of the pieces being welded are the toughest because the heat has nowhere to go, and it blows through. Smaller tacks, or using a heatsink helps. If the speed thing frustrates you, keep a wet cloth nearby and cool the weld down immediately. That will speed up the project and help prevent warping. BTW if the speed thing does annoy you, don't ever buy a TIG because it is even slower

Actually, I'd never heard about stitch Welding until John mentioned it. Sounds like a good idea. I think I get the idea. It shouldn't be hard to add heatsink.

FWIW, I'm not worried about speed. My only deadline anymore now is at the cemetery.

One last tip—if you are using magnets to hold your pieces together (as many people do), stop doing this. In thin sheet it plays havoc when welding within close range. Either rig something different, or use the clamp set I referenced above. You will see a difference.

I was thinking I would put in a few pop rivets to hold things together until I can get enough weld on.

If you are still frustrated after converting to gas, post some pics of your project/coupons and I'm sure we can walk you through set up and welding online. Lots of great videos on YouTube, but if you can't find one that is a close match to your problem, I'm happy to replicate it as best as I can in my shop and do a video for you.

That would be appreciated. Let's see where I get to first.

Turns out my granddaughter has come to the farm for a vacation. So it might be a bit before I can evaluate all this.

Some questions :

What kind of gas pressure is appropriate for a mig 180 at minimum settings? And does the gas pressure need to be changed for different speed/voltage settings?
 

Six O Two

(Marco)
There's a youtube channel called 'Fitzee's Fabrications', he's a custom car guy in Newfoundland. It's a lovely channel really, with good tips on autobody restoration mostly. He recently did a video called "Welding sheet metal. Shielding gas or flux core??". IIRC, it covers a lot of your questions.
 

CalgaryPT

Ultra Member
Vendor
Premium Member
I didn't know that the dials were continuous! After looking at it just now, the feed rate even feels continuous, but the voltage has detents and won't go below A. I'll have to see if I can measure it to confirm that it actually is continuous. But regardless, I had everything on the lowest settings so I don't think that will help. But gas might! It would be great to go to 24gauge, but I'll be happy at 16.
Perhaps I am wrong about that if it is a newer model Donyboy73 did a nice review of it. On his there are no detents, and I have used that model as well. Maybe his is new and the C stands for continuous? Either you can work around the detents with a little more stickout.

I don't think hiding the weld pool will matter much for me. I can't see anyway. Bet you a coffee you're wrong.

I've done lots of stick Welding and flux core mig on heavy metal. I've even done aluminium in the past. But I've never ever laid a bead I could be proud of. Yeah, that's your issue. Sheet metal is way different than welding plate. And again it really sounds like you just need a decent lesson to get a bead you are proud of. I shake too, and my eyesight sucks. Do you use a auto darkening helmet? That's another big help.



So, a body shop guy toward Windsor fixed my wife's jeep recently. In casual conversation, he offered to help me get started with mig. I plan to take him up on that. Good idea.


Those PA Clamps look like they are designed to create a gap. Are they supposed to yield a gap? What if I am overlapping? Check out
. If you are overlapping you don't need them. Personally I can get closer without them, but everyone is different; some guys love them.
Actually, I'd never heard about stitch Welding until John mentioned it. Sounds like a good idea. I think I get the idea. It shouldn't be hard to add heatsink. A cheap flat of copper works great. You must stitch with sheet metal.


I was thinking I would put in a few pop rivets to hold things together until I can get enough weld on. Too much work. But if you go that route use Clecos (temporary rivets):


Some questions :


What kind of gas pressure is appropriate for a mig 180 at minimum settings? And does the gas pressure need to be changed for different speed/voltage settings? I've had mine set for 20-25 CFH for years. Only if I weld 1/2 plate do I crank it up a bit. Here's a chart: https://toolsworking.com/how-to-adjust-mig-welder-settings/
 

CalgaryPT

Ultra Member
Vendor
Premium Member
One last thing I'll add, then I will shut up. Just because you've mentioned how bad your welds are...there is something you should check with your welder. Look in your manual for the correct polarity for flux vs MIG. Flux core wire uses DCEN (negative polarity). MIG uses DCEP (positive polarity). On your machine you swap the lugs the short thick wire inside is connected to. If you have the wire on the wrong lug, the polarity is reversed and your welding will suck no matter how much you practice. Double check this because you wouldn't be the first guy this has happened to and took years to figure it out. If it is on the correct lug for flux now, you'll have to change it over for gas anyways, so it's good to learn.


1637301080804.png

1637301220326.png
 
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Susquatch

Ultra Member
Premium Member
One last thing I'll add, then I will shut up. Just because you've mentioned how bad your welds are...there is something you should check with your welder. Look in your manual for the correct polarity for flux vs MIG. Flux core wire uses DCEN (negative polarity). MIG uses DCEP (positive polarity). On your machine you swap the lugs the short thick wire inside is connected to. If you have the wire on the wrong lug, the polarity is reversed and your welding will suck no matter how much you practice. Double check this because you wouldn't be the first guy this has happened to and took years to figure it out. If it is on the correct lug for flux now, you'll have to change it over for gas anyways, so it's good to learn.


View attachment 18373

View attachment 18374

Yes, I did know about the polarity and it is set correctly.

Funny, cuz that's what the guy at the gas supply place said too.

Please don't shut up. Every time you open your mouth I learn something!
 

Susquatch

Ultra Member
Premium Member
Perhaps I am wrong about that if it is a newer model Donyboy73 did a nice review of it. On his there are no detents, and I have used that model as well. Maybe his is new and the C stands for continuous? Either you can work around the detents with a little more stickout.

Nice welds in that video. And he claims to be a newbie! I'm cooked.

Ya, both his dials are continuous dials. Only my feed is continuous. My voltage has detents.

Do you have any idea what the voltages are and what the waveform looks like? I'd hate to destroy a good multimeter testing it.
 
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