mig gas and how long is a piece of string?

yachtweld3mm · Sat Sep 21, 2019 4:03 am

greetings !
just bought a MIG TIG STICK and some o.8 fluxcore wire. Man it looks like I'll have to spend 8 hours a day doing beads for months before I would even attempt joining metals and I went flux core cause gas here is $ 300 minimum.
$200 bottle deposit, + $ 99 a hit for refils of what is called a D size cylinder- (2.1 M3 / 74.1 cubic feet).
Behold the question!
If I purchased that gas , 2.1 cubic metres / otherwise known as 74.1 cubic feet how many hours or days of laying beads would that roughly provide ??????
yeah I know, and what will the salesman's 2nd cousins neighbor think of perpendicular interment !
THANKS.
PAT APPLETON.

noddybrian · Sat Sep 21, 2019 4:25 am

How much gas you use is effected by a few things including gas shroud size / amps used / weld size / weld position ( fillets take less than open corner etc ) if your indoors with absolutely no draft or trying to weld outside - the list goes on but I'd say you wont get away with less than 25 CFH - you may well need more - I think if you say 30 CFH is realistic & your bottle will give you trouble before being totally empty you will get just over 2 hours of welding done - that's continuous weld - not counting set up time / waiting for cool down / re-positioning etc - that gas does sound expensive - I assume your only choice for argon mix is being ass raped by a big company like BOC or whatever they call themselves down under - maybe someone else from your neck of the woods can advise if there is anyone better priced ? an alternative is go to your favorite pub & ask the guy if he can do you a deal on a bottle of CO2 - this is sold by liquid weight rather than gas volume & is a cheap option - it's not as nice to weld with & the window of WFS to voltage is fairly small but once dialed in can weld quite decent - if you have variable inductance on your machine this helps alot too.

Oscar · Sat Sep 21, 2019 11:42 am

noddybrian wrote:How much gas you use is effected by a few things including gas shroud size / amps used / weld size / weld position ( fillets take less than open corner etc ) if your indoors with absolutely no draft or trying to weld outside - the list goes on but I'd say you wont get away with less than 25 CFH - you may well need more - I think if you say 30 CFH is realistic & your bottle will give you trouble before being totally empty you will get just over 2 hours of welding done - that's continuous weld - not counting set up time / waiting for cool down / re-positioning etc - that gas does sound expensive - I assume your only choice for argon mix is being ass raped by a big company like BOC or whatever they call themselves down under - maybe someone else from your neck of the woods can advise if there is anyone better priced ? an alternative is go to your favorite pub & ask the guy if he can do you a deal on a bottle of CO2 - this is sold by liquid weight rather than gas volume & is a cheap option - it's not as nice to weld with & the window of WFS to voltage is fairly small but once dialed in can weld quite decent - if you have variable inductance on your machine this helps alot too.

So this is off-the-wall, as in, just another one of my crazy ideas. The hamster wheel is always going a million RPM's, lol.

So a few weeks ago, I was experimenting with extending my MIG nozzles in a attempt to cut down on shielding gas usage compared to what some wire manufacturers recommend with dual shield wires. I was able to prove (to myself, not perhaps in general), that shielding as usage can be controlled by correct applications of MIG gas nozzles. This is my thread:

project: lowering flowrates for dual shield flux core

In an extreme generalization, my mind's eye can envision a specially shaped (and properly sized) shielding nozzle(s) to almost completely envelope the wire stickout and bead, with only minimal amount of clearances for the shielding gas to exit where the bead is built-up. While this is completely impractical because it provides zero visibility of the weld pool, I think it could actually "work" to provide an acceptable weld joint while saving massive amounts of shielding gas for our friends in Aus, or any other remote location where welding gas prices are insane. I can see a hybrid copper-pyrex-copper MIG nozzle to get the clearances [to the workpiece-joint-bead] small (to reduce needed flowrate), while having a clear pyrex middle section so you can peek at the weld pool like you sometimes can when using clear cups in TIG welding, "looking through the cup" as Jody has mentioned in his videos. I would be willing to bet you could theoretically get away with something crazy like 5 CFH with a precisely engineered MIG nozzle.

The huge disadvantage is that the MIG gun's duty cycle would be reduced drastically since all the arc energy would be encapsulated by the nozzle, thus heating up the whole MIG gun. Unless you water-cool the nozzle.

Anyways, it's just me rambling.

JayWal · Sat Sep 21, 2019 1:51 pm

Like a trailing cup, Oscar. You might be able to set up the first Titanium mig rig [emoji41]

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Oscar · Sat Sep 21, 2019 2:50 pm

Well trailing cups/accessories use extra gas to protect sensitive metals like Titanium. My idea is more of a specialized nozzle that would be only applicable to steel really.

LtBadd · Sat Sep 21, 2019 6:00 pm

Oscar, perhaps a collaboration with Michael Furick?

Oscar · Sat Sep 21, 2019 8:39 pm

I don't think there's a large enough market for such an animal.

drizler1 · Sun Sep 22, 2019 10:06 am

Those prices are exactly why I stick to flux core. It’s fine for all but beer can thick steel. It won’t do things so wonderful and clean and you do need some bit of ventilation . So what? If I did production it would be different but for around the ranch I’ll take the extra time.

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Arno · Mon Sep 23, 2019 6:35 am

Oscar wrote: In an extreme generalization, my mind's eye can envision a specially shaped (and properly sized) shielding nozzle(s) to almost completely envelope the wire stickout and bead, with only minimal amount of clearances for the shielding gas to exit where the bead is built-up.

I guess you could try to frankenstein something like screwing (part of) an alumina TIG cup on the end of a MIG nozzle so you can pretty much touch the workpiece with the insulated end and run/drag it along at pretty much 0 clearance.

Although I'm afraid dirt from spatter inside the cup/end will clog it up fairly rapidly...

Hmmm... Now replace the gas with pellets/media and you have yourself manual-submerged-arc welding

Bye, Arno.

Oscar · Mon Sep 23, 2019 8:45 am

Well you wouldn't be able to drag it at 0 clearance since the height of the built-up bead would interfere with that. Besides yoiu need the gas exiting somewhere. It was just a thought, not like I'm gonna make one, since I don't need one. But perhaps someone else can use the idea.