Thread: Using argon mixture on a CO2 flux core wire

Hi Keith,

No idea really assuming you arent after max penetration.

If you have bottled gas anyway, why use flux core wire?

Stuart

Originally Posted by Stustoys

Hi Keith,

No idea really assuming you arent after max penetration.

If you have bottled gas anyway, why use flux core wire?

Stuart

Beefy is talking about FCAW, not the piddly little self shielded flux core wire that most will be familiar with.
FCAW is a minimum of 1.2mm wire and often 1.6mm. Used for its superior welding characteristics and mechanical properties, it allows greater amperages and deposition rates to be achieved out of position while giving a beautiful weld appearance.
Personally I don't see the point of using argon mixes with fluxcore wire. Presumably you are doing a lot of welding if you are to graduate to fluxcore wire and the extra cylinder rental will easily be accounted for in your gas savings using CO2 - in fact, why not ditch the argon mix and use CO2 for everything.
In case you don't realise, you are going to need a decent power source for FCAW as amperages and duty cycles will be right up there if you are using it to its full potential.
Beautiful process though. I just spent a 12 hour night shift welding a new corner in a R2900 Bogger bucket with 1.6mm Smoothcor 711 running flat out. Smoothcor 711 is specced for either CO2 or Argoshield gas.

Originally Posted by Karl Robbers

Beefy is talking about FCAW, not the piddly little self shielded flux core wire that most will be familiar with.
FCAW is a minimum of 1.2mm wire and often 1.6mm. Used for its superior welding characteristics and mechanical properties, it allows greater amperages and deposition rates to be achieved out of position while giving a beautiful weld appearance.
Personally I don't see the point of using argon mixes with fluxcore wire. Presumably you are doing a lot of welding if you are to graduate to fluxcore wire and the extra cylinder rental will easily be accounted for in your gas savings using CO2 - in fact, why not ditch the argon mix and use CO2 for everything.
In case you don't realise, you are going to need a decent power source for FCAW as amperages and duty cycles will be right up there if you are using it to its full potential.
Beautiful process though. I just spent a 12 hour night shift welding a new corner in a R2900 Bogger bucket with 1.6mm Smoothcor 711 running flat out. Smoothcor 711 is specced for either CO2 or Argoshield gas.

Thanks for the replies lads, and thanks Karl for explaining why dual shield is so good. I've also read that dual shield (gas shielded flux core arc welding) slag is faster freezing than the self shielded slag, and that's why it's much better for out of position welding. Apparently it's the most used welding process for ship building too.

I'm just on a learning binge with my welding at present, focussing a lot on stick welding since buying my cute little Unimig 170 DC inverter. Before that most of what I built (including my plant trailer) was done with solid wire mig. I've never touched flux core, either self shielded or dual shield, but after reading about it I'd love to see what I've been missing (strong as 7018 stick welds, no stops and starts like stick, high productivity, beautiful welds, great out of position capability). I don't have a lot of welding to do (at present) and that's why for now I don't want to be spending hundreds of dollars just to have extra bottles available. I know that cost will be insignificant once I'm making money but I'm in the spending stage of learning and setting up my workshop.

My mig is a 3 phase Cigweld 330SE so I should be able to run at least the 1.2mm wire. I've never used CO2 on solid wire but doesn't it create a lot of heavy spatter ?? It would certainly be good to have one bottle to cover the two processes.

By the way Karl, what is a R2900 Bogger bucket ?. My present industry is tight access excavation but I've never heard of anything like that bucket.

Cheers,

Keith.

Originally Posted by beefy

Thanks for the replies lads, and thanks Karl for explaining why dual shield is so good. I've also read that dual shield (gas shielded flux core arc welding) slag is faster freezing than the self shielded slag, and that's why it's much better for out of position welding. Apparently it's the most used welding process for ship building too.

I'm just on a learning binge with my welding at present, focussing a lot on stick welding since buying my cute little Unimig 170 DC inverter. Before that most of what I built (including my plant trailer) was done with solid wire mig. I've never touched flux core, either self shielded or dual shield, but after reading about it I'd love to see what I've been missing (strong as 7018 stick welds, no stops and starts like stick, high productivity, beautiful welds, great out of position capability). I don't have a lot of welding to do (at present) and that's why for now I don't want to be spending hundreds of dollars just to have extra bottles available. I know that cost will be insignificant once I'm making money but I'm in the spending stage of learning and setting up my workshop.

My mig is a 3 phase Cigweld 330SE so I should be able to run at least the 1.2mm wire. I've never used CO2 on solid wire but doesn't it create a lot of heavy spatter ?? It would certainly be good to have one bottle to cover the two processes.

By the way Karl, what is a R2900 Bogger bucket ?. My present industry is tight access excavation but I've never heard of anything like that bucket.

Cheers,

Keith.

Your 330A mig will run 1.2 fluxcore all day quite happily, 1.6 is probably a bit big, but then again it really is for the big jobs anyway.
I love CO2 as a gas, its penetration profile is more like a stick weld and it is less prone to root run porosity than Argon mix, (really only an issue if welding to code), add to this its superior performance with dirty or galvanised material and what's not to like.
Many make issue of the supposed spatter issue, but a well set up welder doesn't have too many issues and what spatter there is is easier to remove than with an argon mix. It is also much cheaper than argon mix.
An R 2900 is the largest underground loader made by Caterpillar, they are used for loading rock that has been fired. They are a heavy duty bit of gear. The floor of the bucket is 50mm plate and the sides 32mm plate.
I am thinking that most of your restricted access gear will be fairly light, so I would probably lean towards solid wire for most repair jobs but I would look seriously at fluxcore hardfacing wires as a tool in the arsenal.
If you don't need the all positional capabilities of Smoothcor 711 or similar, then KOBE DW-100 is a fine wire in the downhand position and quite a bit cheaper.
Make sure that your PPE is up to scratch with fluxcore as you are dealing with more amperage, more heat and more arc radiation, not to mention the fumes, (solid mig gives off ozone which is actually a toxic gas too).

Karl, thanks so much for your input. You've taught me a few things about CO2 that I never knew. Once this argon bottle is finished with I think I'll try out CO2 and some dual shield wire.

My excavator is only 1.8 ton (just a tad smaller than that R2900), just like you'd hire at Kennards, etc, so there's no really thick stuff. My tiny 200mm bucket I made was done with mig and I've put it under a lot of punishment, levering out concrete, tree roots, etc. I actually expected the teeth holders to bust at the welds, or something else to bust but all the welds have held. So I guess mig is not necessarilly that weak.

Cheers,

Keith.

Originally Posted by beefy

Karl, thanks so much for your input. You've taught me a few things about CO2 that I never knew. Once this argon bottle is finished with I think I'll try out CO2 and some dual shield wire.

My excavator is only 1.8 ton (just a tad smaller than that R2900), just like you'd hire at Kennards, etc, so there's no really thick stuff. My tiny 200mm bucket I made was done with mig and I've put it under a lot of punishment, levering out concrete, tree roots, etc. I actually expected the teeth holders to bust at the welds, or something else to bust but all the welds have held. So I guess mig is not necessarilly that weak.

Cheers,

Keith.

Mig is certainly not weak, it is a low hydrogen process after all.
Where mig loses out to Low hydro sticks and FCAW is in impact toughness and ductility. I might add that CO2 has better figures than Argon mix gas in these areas. Mig also go at bad reputation for not penetrating caused by people that try to put too much weld in each pass, you have to keep the wire at the leading edge of the weld puddle. Not to mention the need to grind back to clean metal if a good weld is desired with any process.
CO2 cylinders use a different fitting than argon, but you can buy an adapter to connect your regulator. You will want to run around 10 - 12LPM flow.
When welding tooth adapters, don't forget to preheat, (when in doubt, preheat is a good rule), as this will reduce Heat affected zone cracking.
One feature of FCAW that can drive you insane is its ability, due to heat input and penetrative abilities, to drag moisture and dirt out of a joint, (talking bucket repair here), leading to the best porosity and worm holes that you will ever see. Sometimes, with bucket wear liners etc, you cannot clean everything out. In these situations, there is only one thing that works - Low Hydrogen stick - do a root run with that and then get out the FCAW.
If repairing buckets and other ground engaging tools, spare a thought for what they have been digging and its reaction to heat. For example, we are a mine that produces zinc, lead, copper, silver and gold. Zinc and lead are both metals that give of toxic fumes, so we need to take all precautions to protect ourselves. I doubt that you dig much lead or zinc, but buckets can give some pretty potent fumes off.
One other little tip, if you are a person that uses tip dip, (I rarely do), then a better and cheaper alternative is cheap spray on cooking oil, I use this if I am doing a lot of galvanised work, the cooking oil doesn't interfere with paint adhesion like some tip dips can.

Thanks for more fantastic info Karl, I could certainly drive you crazy picking your brains. I'd be happy feeding you beers while you fed me knowledge, ha ha.

I've never had a mig weld crack on me but I've had quite a few 6012/6013 stick welds crack, right along the middle of the bead. Always happened on cold metal. So it's not just me, eh ?, that's a known issue welding on cold steel.

I started a thread on welding web about mig and low hydrogen stick, asking shouldn't mig be stronger because of lower hydrogen levels. Someone mentioned that mig is not as tough or ductile but I don't know why. Later I read somewhere that mig cools faster because of a) the gas and b) there's no slag to slow the cooling rate. So far that's the only reason I could guess the mig weld is more "brittle". I never knew about the figures being a bit better for CO2 mig, thanks for that. The reasons for using CO2 are growing - stronger mig and use for dual shield, plus cheaper, hmmm.

You're the second person to mention about moisture coming out of the metal. Seems like one hell of a good reason to preheat any important joints. The other guy that mentioned it said when preheating you can actually see the metal start to sweat as the moisture comes out of the "pores" (pores ? maybe I should clean the metal with some deep skin cleanser from the pharmacy). I've often looked at pictures of horrible rusty peices of machinery that need welding repairs, and wondered how the hell would you clean in those nooks and crannies before welding. OK noted, low hydrogen for that sort of stuff. I've just completed my airtight, argon purged storage tubes for my low hydrogen rods so I'm set up there, got Austarc 16TC and Kobe LB-52U, both in 2.5 & 3.2mm.

Talking about welding fumes, I've just ordered a 3m 7502 silicon mask and some P100 particulate filters. The filters are coming from Korea so I hope they are the real thing. Australia prices are between $25 and $30 per set whereas USA, UK, Korea, China are all about the $7 per set mark. I don't know what's happening here with prices. I've been doing a bit of 2mm galvanised tube welding for shelving in my workshop and have had some rather unpleasant reactions that last all the next day. I was literally bathing in the fumes while welding. Just using a fan to blow the concentrated fumes away now. I would never have guessed about fumes from welding buckets so you've probably saved me feeling ill at some point in the future, thanks.

I've got a tin of that tip dip but on one of the forums someone said it can cause porosity if it gets mixed with the weld so I might try not to use it. I've recently changed the end of my mig gun to use cheaper consumeables. The original one that came with the 330SE had tips that now cost up to $6 each. The new ones I use are 60c each (pack of 10 at Total Tools) so I'm not so concerned about using nozzle dip any more. I wonder if the cheap cooking oil would work as anti-spatter on the metal itself. I've built a cnc plasma cutting table and when cutting smaller holes or on thick pierces I'll spray a bit of anti-spatter in an attempt to reduce the glob of slag at the pierce point, because it can actually get into the cut path if it's big enough.

Cheers Karl, hope you're having a relaxing weekend.

Keith.

Originally Posted by beefy

Thanks for more fantastic info Karl, I could certainly drive you crazy picking your brains. I'd be happy feeding you beers while you fed me knowledge, ha ha.

I've never had a mig weld crack on me but I've had quite a few 6012/6013 stick welds crack, right along the middle of the bead. Always happened on cold metal. So it's not just me, eh ?, that's a known issue welding on cold steel.

Usually it is the weld cracking out of the parent metal in the case of insufficient pre heat. I will always reach for FCAW or Low Hydro stick when all else fails. There is a reason after all that most large pressure piping is still stick welded. Too small a bead can also cause this symptom. A fillet weld should typically have the same leg length and at least 60% throat thickness of the parent metal.

I started a thread on welding web about mig and low hydrogen stick, asking shouldn't mig be stronger because of lower hydrogen levels. Someone mentioned that mig is not as tough or ductile but I don't know why. Later I read somewhere that mig cools faster because of a) the gas and b) there's no slag to slow the cooling rate. So far that's the only reason I could guess the mig weld is more "brittle". I never knew about the figures being a bit better for CO2 mig, thanks for that. The reasons for using CO2 are growing - stronger mig and use for dual shield, plus cheaper, hmmm.

There is not a great deal in it between CO2 and Argon mix ductility and impact wise, however I always raise this point in order to make the case that CO2 is not some second rate gas.

You're the second person to mention about moisture coming out of the metal. Seems like one hell of a good reason to preheat any important joints. The other guy that mentioned it said when preheating you can actually see the metal start to sweat as the moisture comes out of the "pores" (pores ? maybe I should clean the metal with some deep skin cleanser from the pharmacy). I've often looked at pictures of horrible rusty peices of machinery that need welding repairs, and wondered how the hell would you clean in those nooks and crannies before welding. OK noted, low hydrogen for that sort of stuff. I've just completed my airtight, argon purged storage tubes for my low hydrogen rods so I'm set up there, got Austarc 16TC and Kobe LB-52U, both in 2.5 & 3.2mm.

A good illustration of this is when oxy cutting, the moisture can often be seen ahead of the cut. Also when dealing with bucket liners there is moisture and other crap caught between the layers.

Talking about welding fumes, I've just ordered a 3m 7502 silicon mask and some P100 particulate filters. The filters are coming from Korea so I hope they are the real thing. Australia prices are between $25 and $30 per set whereas USA, UK, Korea, China are all about the $7 per set mark. I don't know what's happening here with prices. I've been doing a bit of 2mm galvanised tube welding for shelving in my workshop and have had some rather unpleasant reactions that last all the next day. I was literally bathing in the fumes while welding. Just using a fan to blow the concentrated fumes away now. I would never have guessed about fumes from welding buckets so you've probably saved me feeling ill at some point in the future, thanks.

Ah, I see you've met my old friend Mr. metal fume fever. I experienced him several times in my apprenticeship, (bosses were not always as enlightened as they are now), he will put you in hospital if you spend too much time under his influence. I wouldn't lose too much sleep over your buckets, but nevertheless, be overprotected rather than under.

I've got a tin of that tip dip but on one of the forums someone said it can cause porosity if it gets mixed with the weld so I might try not to use it. I've recently changed the end of my mig gun to use cheaper consumables. The original one that came with the 330SE had tips that now cost up to $6 each. The new ones I use are 60c each (pack of 10 at Total Tools) so I'm not so concerned about using nozzle dip any more. I wonder if the cheap cooking oil would work as anti-spatter on the metal itself. I've built a cnc plasma cutting table and when cutting smaller holes or on thick pierces I'll spray a bit of anti-spatter in an attempt to reduce the glob of slag at the pierce point, because it can actually get into the cut path if it's big enough.

It can cause porosity, generally not too bad unless welding to code, but I honestly have never really felt the need for it. Cheap consumables can be a false economy as they are often shorter lived at high amperages, but you will soon work this out and buy what works best, (some generics are excellent though). I think cooking oil as a general anti spatter spray may present issues of mess. Once again, I don't use the stuff unless welding a lot of galvanised, even then it is only on the nozzle. Spatter on a bucket doesn't really matter and on galv doesn't stick.

Cheers Karl, hope you're having a relaxing weekend.

Keith.

To be honest, most welding consumables perform better than the operators using them and if used for their intended purpose and in accordance with good practices, they rarely fail, meaning that the end decision is commonly based upon operator perceptions and preferences.

Thanks again Karl,

this thread is going in my collection of welding info.

There's so much "real world" info guys like yourself teach us amateur welders, and a lot of it is never found in welding books written by accomplished welders. Most tend to just go over the main theory and that's it. All the info I've collected on avoiding porosity with low hydrogen electrodes has came from forums for example. It's the next best thing to the days before internet where you'd have to actually be chatting with an experienced welder to learn these things.

Interesting to know that stick welding is still the main process on high pressure pipelines. Makes my feel a bit better about focussing quite a bit on my stick welding at present, despite having my chunky mig sitting there. From the small amount I've learned about dual shield, I thought it was just as good/strong as LH stick welding in every respect so I wonder why stick is still preferred. Well there is the wind factor of course which can blow the shield gas away.

Cheers,

Keith.

Originally Posted by beefy

Thanks again Karl,

this thread is going in my collection of welding info.

There's so much "real world" info guys like yourself teach us amateur welders, and a lot of it is never found in welding books written by accomplished welders. Most tend to just go over the main theory and that's it. All the info I've collected on avoiding porosity with low hydrogen electrodes has came from forums for example. It's the next best thing to the days before internet where you'd have to actually be chatting with an experienced welder to learn these things.

Interesting to know that stick welding is still the main process on high pressure pipelines. Makes my feel a bit better about focussing quite a bit on my stick welding at present, despite having my chunky mig sitting there. From the small amount I've learned about dual shield, I thought it was just as good/strong as LH stick welding in every respect so I wonder why stick is still preferred. Well there is the wind factor of course which can blow the shield gas away.

Cheers,

Keith.

Definitely not a strength issue with Fluxcor welding on pipelines. Fluxcor will stay with the best Low Hydrogen electrodes in that respect.
The reason is partly what you concluded as regards the issue of the gas shield being blown away, but also an issue of access and manipulation. An elecrode is far more compact and can access tight vee preps far more easily. If prefabbing components that were on a rotator for example, fluxcor would be the weapon of choice, but for pipelines that cannot be rotated, stick welding is the order of the day. For smaller pipe diameters, Tig is more common or sometimes a tig root run and low hydrogen stick fill and capping runs.
There are some new processes coming into being, one being STT, (surface tension transfer), welding, this seems to me to be a highly controlled form of mig welding where wire speed, voltage and amperage are idividually controlled, (standard mig tie amperage and wire speed together).
Stick also has one unassailable benefit, that of portability. Many pipelines are in tight access conditions and you can literally tie knots in a welding lead with no negative effect, just try to do that with a mig lead and you will soon find wirefeed issues present themselves. Some top welders even weld using a mirror in tight conditions where they cannot physically access the area.
I love my mig and Fluxcor, but if I were limited to one welder, it would be a stick welder, they are just that versatile.
Actually one of my real beefs with the trade at present is with the advent of the "Choose your own adventure" tailored apprenticeships currently in vogue, stick welding is often missed out by many employers. All well and good if you never leave a workshop environment. In my previous employment out of four tradesman and two apprentices, we had one competent stick welder and one very semi competent, as for the apprentice, I think he gave up when he couldn't light them with a cigarette lighter - I'm sure he thought they were some exotic form of sparkler.

Don't want to hijack this thread but have been reading this thread with interest.

I have a question for Karl, how does welding with co2 instead of an argon mix compare to gassless mig wire for ease of use and amount of smoke.

How difficult would it be to weld thin wall rhs 1.6mm with co2 for a less experienced operator.

I currently mig weld with gassless mig wire and Can weld ok with it. But I really hate the large amount of smoke, I can tolerate the spatter.

I have considered converting my welder to using an argon mix however I don't use it enough to justify the cost.

So I am wondering about using co2?

Thanks Pete

There's been other threads here about MIG with CO2. I went that way due to my relatively low usage About $200 delivered for a beer gas cylinder off Ebay, $60 or something for the proper CO2 regulator/flow meter - the cylinder did me about 6 months and then about $70 to refill at the local homebrew shop.

As for fumes/smoke - none apart from what comes off the burning galvanising/paint, and the shield gas blows it away from the arc. 1.6mm is no problem - below 1mm it starts getting a bit hairy. Weld profile tends not to be as flat as an Argon/CO2 mix. I weld mostly Duragal, and you do get a bit of spatter, but nothing like flux core.

Thanks for the info Rusty

Originally Posted by Karl Robbers

Definitely not a strength issue with Fluxcor welding on pipelines. Fluxcor will stay with the best Low Hydrogen electrodes in that respect.
The reason is partly what you concluded as regards the issue of the gas shield being blown away, but also an issue of access and manipulation. An elecrode is far more compact and can access tight vee preps far more easily. If prefabbing components that were on a rotator for example, fluxcor would be the weapon of choice, but for pipelines that cannot be rotated, stick welding is the order of the day. For smaller pipe diameters, Tig is more common or sometimes a tig root run and low hydrogen stick fill and capping runs.
There are some new processes coming into being, one being STT, (surface tension transfer), welding, this seems to me to be a highly controlled form of mig welding where wire speed, voltage and amperage are idividually controlled, (standard mig tie amperage and wire speed together).
Stick also has one unassailable benefit, that of portability. Many pipelines are in tight access conditions and you can literally tie knots in a welding lead with no negative effect, just try to do that with a mig lead and you will soon find wirefeed issues present themselves. Some top welders even weld using a mirror in tight conditions where they cannot physically access the area.
I love my mig and Fluxcor, but if I were limited to one welder, it would be a stick welder, they are just that versatile.
Actually one of my real beefs with the trade at present is with the advent of the "Choose your own adventure" tailored apprenticeships currently in vogue, stick welding is often missed out by many employers. All well and good if you never leave a workshop environment. In my previous employment out of four tradesman and two apprentices, we had one competent stick welder and one very semi competent, as for the apprentice, I think he gave up when he couldn't light them with a cigarette lighter - I'm sure he thought they were some exotic form of sparkler.

Cheers Karl, good knowledge.

Reading some posts from pipeline welders they would mention how they learned to stick weld with both hands. I can only guess that must be for reasons of access too. But what you mentioned about a mirror, that's amazing. Now I'll know the welder doesn't just like admiring his own face when I see a mirror in his bag, LOL.

I don't know if I'd myself laughing or feel sorry for that apprentice. Who thought of doing that to him