MIG welding with CO2 question

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Eugen Canada
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MIG welding with CO2 question

Post by Eugen »

Hello you welders here, about a month ago I came across a Linde 220 MIG welding machine at a very low price, in poor cosmetic shape. Not clear it works, I don't have 220V yet in the shop. The guy said he's 99.9% sure it'll work. Well, since then I've been looking for a bottle of argon/co2 mix.

A 20 lbs full, steel bottle of CO2 showed up on marketplace for $50 in Toronto today and I happened to be in the big city for work. Luckily the pick up location was also close to crankshaft grinding shop which I was going to visit anyways to pick up the k321 crankshaft. I had heard that you can use CO2 in mig welding but it won't be very pretty.

The welder came with a regulator. My question is, are the regulators for argon different than those for co2? My common sense tells me they shouldn't be different, after all a common gas for MIG welding is a mix of the two gases, right?

I welcome any and all advice you might have for this greenhorn. :geek:
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Re: MIG welding with CO2 question

Post by Spike188 »

Eugen,

Welding and cutting gas suppliers rent their bottles for a set price per month. When the bottle is empty they will replace it with a full one. If the customer use enough gas they may rent multiple bottles of the same gas so they will never be stranded mid job.

Years ago TSC Canada now using the trade name Peavey Mart started selling Praxair bottles that you own outright and no rental on. Because I go through less than 1 bottle per year of each of the 3 gases, oxygen, acetylene, and mig mix, purchasing the bottles outright was a huge savings over renting.
Another advantage is Peavey Mart store hours made picking up refills on weekends or late evenings possible.

Years ago there were multiple gas suppliers within close distance. In a pinch a person could return a rented bottle to the supplier and exchange on the fly as long as it was a normal business day.

I have owned my bottles for 15 years, At the time of purchase, bottle rent was $12 dollars per month. I would have paid $450 per year rent for the three bottles plus gas. I should compare options to see if Peavey is still my best option.

As far as you question about gas goes, gas type and blend requirement depend on the material being welded. "Mig mix gold" is a general purpose blend of gas that works well with most steel.

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Re: MIG welding with CO2 question

Post by Harry »

You can "MIG" GMAW with CO2 but the adjacent area to the weld will have spatter, little balls of metal sticking to the base metal. For most applications it's a matter of economics. CO2 is cheap and if the weld appearance doesn't matter than CO2 is a good choice. I usually use C25 which is 75% Argon and 25% CO2. It gives a good weld appearance with minimum spatter if the weld parameters are set correctly. To high a voltage setting and wrong angle of the gun can cause spatter also. These gases are used for what's know as short circuiting transfer, where the wire short circuits on the base metal. Gases such as 95% to 98% Argon and 2% to 5% Oxygen can be used for what's called spray transfer. This is usually at a higher voltage and amperage settings and used for thicker metals. The gas becomes ionized or electrically conductive and the wire forms into little droplets and is sprayed across the arc. Usually only used in the flat position, but newer inverter technology machines can pulse the voltage and amperage settings. This pulsing can change the heat into the arc and out of position welding can be acquired. These newer inverter machines are the way to go if your going to do a lot of GMAW welding.
I have my own tanks for Oxygen and Acetylene. Also for C25 and straight Argon for TIG welding. I get them filled at a small supplier and at a better price than The larger suppliers like Praxair. Some of my friends from the American Welding Society work at Praxair and they have recently been acquired by a German Company Linde Air.

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Re: MIG welding with CO2 question

Post by DavidBarkey »

Personally I prefer flux core . Burns hotter and deaper with less currant that on the bottle . Added bonus is that the gas does not blow away in a stiff wind when doors are open . Ya there is more clean up to do , but most of what I do need function over fashion .
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Re: MIG welding with CO2 question

Post by Harry »

Dave I use both GMAW "MIG" and FCAW "FLUXCORE". Different welding process for different applications. There is gas shielded fluxcore and gasless fluxcore. Yes when using gas it may drift away from the weld zone and should only be used indoors and not have a fan blowing the shielding gas away either. Fluxcore is a little more forgiving like SMAW "STICK" when welding on dirty metal. I like mig for welding sheet metal and stick for welding thicker materials.

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Re: MIG welding with CO2 question

Post by Eugen »

DavidBarkey wrote: Sat May 29, 2021 7:03 am Personally I prefer flux core . Burns hotter and deaper with less currant that on the bottle . Added bonus is that the gas does not blow away in a stiff wind when doors are open . Ya there is more clean up to do , but most of what I do need function over fashion .
Dave
Dave, what wire do you use with flux core? My flux core machine works on 120V only.
Last edited by Eugen on Sun May 30, 2021 11:14 pm, edited 1 time in total.
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Re: MIG welding with CO2 question

Post by DavidBarkey »

Eugen wrote: Sat May 29, 2021 10:28 am
DavidBarkey wrote: Sat May 29, 2021 7:03 am Personally I prefer flux core . Burns hotter and deaper with less currant that on the bottle . Added bonus is that the gas does not blow away in a stiff wind when doors are open . Ya there is more clean up to do , but most of what I do need function over fashion .
Dave
Dave, what wire do you use with flux core? My flux core machine works on 120V takes only.


I use 211-MP .035" in my mig in my 120v Lincoln. The biggest thing for you would be to make sure you have 20 am receptacle and no line loss from light weight extension cords . Cords no less than 12 gauge to be use if at all . For the heavier metals I will tack and some time root weld with mig and then finish with stick .
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Re: MIG welding with CO2 question

Post by Eugen »

So I got one of those inverter machines that works on 120V on sale last summer and used it with the same wire as you Dave, to weld some sides on the trailer. This picture shows what it looked like when after I got the hang of it. You can clearly see I am inexperienced, but the weld holds, I hit it pretty hard with a hammer to see what would happen. :|
weld1.jpeg
I happen to have a 220 stick welder, and now got the non-functional 220 MIG but these two machines I can't use until I pull 240V to the shop, which unfortunately needs about 75 feet of direct burial 6/3 cable, expensive as hell. Plus all the work. Ugh!
Last edited by Eugen on Mon May 31, 2021 2:54 pm, edited 1 time in total.
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Re: MIG welding with CO2 question

Post by DavidBarkey »

Eugen wrote: Mon May 31, 2021 12:31 pm So I got one of those inverter machines that works on 120V on sale last summer and used it with the same wire as you Dave, to weld some sides on the trailer. This picture shows what it looked like when after I got the hang of it.

weld1.jpeg

I happen to have a 220 stick welder, and now got the non-functional 220 MIG but these two machines I can't use until I pull 240V to the shop, which unfortunately needs about 75 feet of direct burial 6/3 cable, expensive as hell. Plus all the work. Ugh!
When welding with flux core , think of it a continuous feed stick. most the stick rules apply

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