WHAT GAS TO USE WITH FLUX CORE WIRE

i've heard many times that FCAW works best with shielding gas. the other day at school, the instructor let me try an FCAW setup, i tried welding with no shielding gas and there was a ton of porosity and there was no slag to chip either. i thought the main point of flux core is portability because you don't need shielding gas, and its basically the wire feed equivalent of stick, but if you still need external shielding gas to work properly, then why not just use standard GMAW instead?
There are actually two different types of flux cored wire that are recognized by the aws as (fcaw). Fcaw-s is self shielded and requires no shielding gas. Fcaw-g ( dual shield) requires shielding gas. Look up the wire that your instructor let you run. Im wondering if perhaps it's a metal - cored wire (example Lincoln mc710) that was was called fcaw back in the day but is now classified as composite gmaw these days. It leaves no slag.
 
There are actually two different types of flux cored wire that are recognized by the aws as (fcaw). Fcaw-s is self shielded and requires no shielding gas. Fcaw-g ( dual shield) requires shielding gas. Look up the wire that your instructor let you run. Im wondering if perhaps it's a metal - cored wire (example Lincoln mc710) that was was called fcaw back in the day but is now classified as composite gmaw these days. It leaves no slag.
Good info,did not know that. had never heard of the stuff.

As an aside, one of the last I-CAR classes I took covered welding the various high strength steels that are now so common in vehicles. Several manufacturers specify a specific type of MIG wire that has to be used when plug welding. Honda is one of them. Checkout the cost of the wire that is approved by Honda.


9-10X the cost of regular ER70S6! Really it's at the point that you have to have a very expensive ($25K or more) modern resistance spot welder like the models Pro-Spot has, in order to safely repair a late model. Plug welding in any panels is almost a no-no now.
 
E71T-1C/1M is both gas and flux, it usually starts at thicker mild steel, like .045.

E71T-GS is the pretty standard flux core wire for steel, need to reverse your polarity.

They even have E308LT0-3 is gasless, flux core for stainless and yeah, you can weld stainless with mild steel or mild steel with stainless if you want the tougher grinding and pay over 100 for a 10 pound roll compared to 35 or so..

Get to metal cored wire, you have different wires that are better for vertical welds, rusty metal, just cannot use it. I did move up from .023 to .035 in my lincoln with gas, still not a big difference if I want to do the sheet metal tacks all around. If I do a bead, its fine, just tack tack tack and junk junk junk. The common sense in me thinks there is no way the gas can make it all the way to the nozzle 10 feet away each time I tick the trigger. Watching some Kindigit or Martin Brothers show I always look out for the flowmeters. I did see one barely moving with a tack tack roof weld, but that is me again thinking, how can even less flow get way the hell out there?

If I have time I have gotten some better luck with Kiswel wire on ebay for my hobart. Just stuck with the lincoln wire for the lincoln welder.

I still cannot find anyone to sell me straight CO2 because they all say I should not use it. But if the stuff you are supposed to do does not work, then who knows.
 
Recommended flow for sheet with either 75/25 or 100% CO2 is around 15 CFM/HR. 100% CO2 might work ok for thicker stuff but it makes for very hard welds when doing sheet. 75/25 suits much better for automotive sheetmetal welding, or if you have a welder capable of spray transfer you need to go minimum 80/20 argon/co2. This is assuming you are using solid wire of course. Flux cored I know almost nothing about, other than I don't want to use it. Heavy stuff outdoors conventional stick welding works pretty good for me.
What are the issues you are having?
 
Recommended flow for sheet with either 75/25 or 100% CO2 is around 15 CFM/HR. 100% CO2 might work ok for thicker stuff but it makes for very hard welds when doing sheet. 75/25 suits much better for automotive sheetmetal welding, or if you have a welder capable of spray transfer you need to go minimum 80/20 argon/co2. This is assuming you are using solid wire of course. Flux cored I know almost nothing about, other than I don't want to use it. Heavy stuff outdoors conventional stick welding works pretty good for me.
What are the issues you are having?
What I would call terrrible porosity. Little sap tack and you can see three or four holes in the tack. If I get to 1/8 plate and can run a full bead, it looks better, but mostly on top of the metal. It glows OK so I know it is welded, but its really up on top.

I got the lincoln fabricator at a pretty good deal, a 140 amp machine I figured I would keep for the thin stuff where I go to .250 with the Hobart machine The I beam I got for my frame table was .375 on the thick side of the taper and the Hobart all the way up just does beautiful almost stick weld looking joints with the flux core. Tried to do the gas and I see very little glow on .125, mostly spotty. Tried everything of cleaning better, wire brushing everything, different size nozzles, I just cannot see how the gas gets to the nozzle from a 15 foot cable with the zap zap welds.
 
What I would call terrrible porosity. Little sap tack and you can see three or four holes in the tack. If I get to 1/8 plate and can run a full bead, it looks better, but mostly on top of the metal. It glows OK so I know it is welded, but its really up on top.

I got the lincoln fabricator at a pretty good deal, a 140 amp machine I figured I would keep for the thin stuff where I go to .250 with the Hobart machine The I beam I got for my frame table was .375 on the thick side of the taper and the Hobart all the way up just does beautiful almost stick weld looking joints with the flux core. Tried to do the gas and I see very little glow on .125, mostly spotty. Tried everything of cleaning better, wire brushing everything, different size nozzles, I just cannot see how the gas gets to the nozzle from a 15 foot cable with the zap zap welds.
The hose does not empty every push of the trigger. It stays full of gas. The key is to purge the hose before you start welding. Once you start it works fine. Some welders have a purge setting that disables the wire feed while you purge the hose.

Don
 
Good info,did not know that. had never heard of the stuff.

As an aside, one of the last I-CAR classes I took covered welding the various high strength steels that are now so common in vehicles. Several manufacturers specify a specific type of MIG wire that has to be used when plug welding. Honda is one of them. Checkout the cost of the wire that is approved by Honda.


9-10X the cost of regular ER70S6! Really it's at the point that you have to have a very expensive ($25K or more) modern resistance spot welder like the models Pro-Spot has, in order to safely repair a late model. Plug welding in any panels is almost a no-n

Good info,did not know that. had never heard of the stuff.

As an aside, one of the last I-CAR classes I took covered welding the various high strength steels that are now so common in vehicles. Several manufacturers specify a specific type of MIG wire that has to be used when plug welding. Honda is one of them. Checkout the cost of the wire that is approved by Honda.


9-10X the cost of regular ER70S6! Really it's at the point that you have to have a very expensive ($25K or more) modern resistance spot welder like the models Pro-Spot has, in order to safely repair a late model. Plug welding in any panels is almost a no-no n

Good info,did not know that. had never heard of the stuff.

As an aside, one of the last I-CAR classes I took covered welding the various high strength steels that are now so common in vehicles. Several manufacturers specify a specific type of MIG wire that has to be used when plug welding. Honda is one of them. Checkout the cost of the wire that is approved by Honda.


9-10X the cost of regular ER70S6! Really it's at the point that you have to have a very expensive ($25K or more) modern resistance spot welder like the models Pro-Spot has, in order to safely repair a late model. Plug welding in any panels is almost a no-n
Good info,did not know that. had never heard of the stuff.

As an aside, one of the last I-CAR classes I took covered welding the various high strength steels that are now so common in vehicles. Several manufacturers specify a specific type of MIG wire that has to be used when plug welding. Honda is one of them. Checkout the cost of the wire that is approved by Honda.


9-10X the cost of regular ER70S6! Really it's at the point that you have to have a very expensive ($25K or more) modern resistance spot welder like the models Pro-Spot has, in order to safely repair a late model. Plug welding in any panels is almost a no-no now.
Er120!!!! Holy moly, what grade of steel is honda using?
 
It's designed for the high strength steels all manufacturers are using now. Any welding on HSS or HSLA weakens it (heat tempers it, that alloy is an attempt to lessen the amount of weakening. Almost have to do everything with a high powered inverter based spot welder like what Pro-Spot sells. And been my experience welding HSS that it's pretty miserable trying to plug weld if you don't have pulse type MIG welder.

Here is one of two 2015 Jeep Cherokee's that I did at the same time, that used HSS in nearly all the steel body parts. This was back in 2015. New (1000 miles) 2015 Jeep Cherokee that was totaled and we (me) rebuilt it for a large salvage rebuilder in our area.

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Here is what the rails looked like when I tore it down some.
IMG_20160427_144101529.jpg


Here is my first attempt at trying to pull the rails back around. Stuff they use is strong and it takes a "set" after a hit like that. I figured I could pull them around enough to make it easier to section them and replace what I had to. Figured they would tear but that was fine, just wanted them back around. Steel was so strong that they barely responded to using two 10 ton towers and nearly full pressure. They actually started to move farther back on the rail which is not what I wanted. Ended up cutting them like they were and sectioning "new" salvage yard cut rails in. And I had to do it without removing the engine, cause that was "too much extra labor cost". :mad: Ended up splitting the "new" ones in two and making offset butt welds, then doing modified I-CAR sleeves on the inside of each side. Hopefully the extra sleeving made up for in strength with what was lost because of the welding. But who knows? And nobody seemed concerned about this except me. This vehicle was one of the reasons why I don't want to ever rebuild heavy structural damage without the proper tools again. Meaning a spot welder that can do structural welds. It's not like it was 25-30 years ago when I was a kid and guys were rear roof clipping Cadillacs and other cars. Peoples lives are at stake with this stuff.

IMG_20160428_124312390.jpg


Showed this pic before but here is what it looked like just after finishing painting it. Managed to only have to paint the hood, fenders and blend into the front doors. Used Euro Clear on this one. 105 degrees in the booth when I shot it too. No buffing.:) Love Euro for collision work. I don't love collision work though.:)
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Oh and not to toot my own horn but I was pretty proud of the fact fact that in the shit shop I did this in, I had no measuring system, only a tram gauge and when I completed it, wheel alignment went perfectly, completely within spec. I felt pretty good about that.
 
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The hose does not empty every push of the trigger. It stays full of gas. The key is to purge the hose before you start welding. Once you start it works fine. Some welders have a purge setting that disables the wire feed while you purge the hose.

Don
Thank you, this is definitely something I did not try. I will give it another shot. Just how my brain works sometimes. If there were a mini gas solenoid up at the gun that would open for gas I think I could buy into it more. It is the first time I got the purge direction, or suggestion.
 
The most often used shielding gases are either straight carbon dioxide or argon carbon dioxide blends. The most common blend used is 75% Argon 25% Carbon Dioxide. This particular style of FCAW is preferable for welding thicker and out-of-position metals. The slag created by the flux is also easy to remove. shareit vidmate app
 
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