CO2 for MIG

[Blown S-10]

i need a refill of gas. i remember reading a thread about CO2 for MIG. i searched, but can't find the thread.

so, can you refresh/clarify my memory on this subject. i want to get the most i can out of my little 135, and remember CO2 will give better penetration, and thought i wanted to try it. can i use my C25 tank/regulator ?

please fill me in on the plus's/minus's

[HAWK]

Blown S-10,

CO2 will give deeper overall penetration with a trade off of increased spatter. It is most often recommended for dual shield flux wires and some .045" bare wires in high amperage applications. You will have to pick up a CO2 regulator. The CO2/argon regulator will freeze up and won't function with 100% CO2 shielding gas. A 75%argon/25%CO2 or C25 as it is commonly referred to is probably your best choice for your 135 unit. CO2 is somewhat cheaper than the C25 mix, but you won't see much difference with your machine.

[hankj]

I can't believe I'm about to disagree with HAWK, but here goes: I repaired a little windmill fan for a neighbor recently. It was sheet metal about 22ga. or so - made in China. I blew holes in it with the MM135 using CO2, but switched to C-25 and got a sweet tack that held up enough so I could repair the blow-through areas.

I use the Smith regulator that came with the MM135 for CO2. It sweats pretty good at 20CFH, but has never frozen. I concede that that may be different in Soth Dakota in the winter, though.

As for the spatter thing, I don't get any to speak of using CO2 if I'm set up right.

Blown S-10, you won't be able to use your C-25 tank for CO2. C-25 is stored as a high pressure gas; CO2 is stored as liquid. The cylinder is much less sturdy than a high-pressure cylinder.

Hank

[Blown S-10]

thanx guys

i seem to remember that the CO2 lasts twice as long, true ?

i guess i will just keep my eye open for a used tank & regulator. then i will give it a try.

[fun4now]

regulator

book clearly states that you can not use the c-25 reg. with strait O2 if you(hankj) have done it i gess it can work but is not recomended and if you do trash it it wont be worantied. i'm not shoure that i would want to risk it gages are made for spacific type/temp/presher not realy a good ideal to mess around in that area. a new gage dosent caust that much and it will caust you even more if it fails

[Teeps]

I agree that gas is all about what your going to weld on.

CO2 runs hot, and Helium even hotter,

Thinks like ARGON help with cooling things down, and less oxidation.

Use as much Argon as you can, and still maintain proper penetration and weld puddle to fuse the joint, and make a proper weld.

Thicker metals will require more 02 or c02 or helium, to wet the puddle out enough, and have enough penetration, but especially with 02 and C02 you may also get more oxidation/ and later on corrossion.

22 guage mild steel, c25 is perfect.
I'm going to try 10% Co2 on stainless, however, I've heard 2% CO2 works well on stainless for nice welds. But I'll be doing 16 guage, if I were welding thick stuff, I'd have to go to a tri-mix, part helium.(and a bigger welder for that matter)

[hankj]

Blown S-10,

The gas properties of the CO2 make it seem like it lasts longer, but consider this:

C-25 is sold as a pressurized gas by the cubic foot. So, an 80CF tank used at a rate of 25CFH will last you about 3 hours and change.

CO2 is sold as a liquid by weight. .12341 pounds of liquid CO2 will make 1CF of gas, so a 20# tank will yield <> 162CF. Running at 20CFH, you'll get a little more than 8 hours welding time.

Physical size of the 80CF C-25 and the 20# CO2 are pretty close, so that's why it "seems" to last twice as long.

That's also why the high pressure guage on the regulator reads over 2000PSI on your C-25 tank when it's new, and that number drops rapidly as you use gas, but the CO2 tank only reads around 500PSI (which is the vapor pressure from the boiling liquid inside) and stays nearly constant until you're out of gas!

Hope that doesn't confuse you. I know what I wanted to say, but sometimes...

Hank

[Blown S-10]

ok guys. what do i look for in a tank ? are they all the same ? i'm going to put an add in a local forum to ask for one. i gotta know what to look for, i don't have much of an idea. are those ones they use for soft drink machines ok ?

[GunLocators]

Are you sure about the pressures on the CO2 being 500psi . I Sold paintball supplies for a couple years and all my gauges read almost 800psi pressure.

[dyn88]

hey gun thats the most confusing board Ive ever seen. Im a member now but seems aw though you can only view one topic at a time.

[BCarlucci]

Teeps,

I've used 95%AR/5%ox for welding on thin S/S, and it runs really smooth on 300 series s/s, not sure what s/s your welding, you could try it out.

BC

[pejenkins]

BLOWN S-10
You can pick up cylinders from a carbonic shop, or a place that handles fire safety equip. I got my CO2 bottle from
Keller fire and safety in K.C. I think I have a 50# bottle (cost about $50.00 + it costs approx $14.00 to fill (at the place I bought it).
The welds do produce some splatter but nothing a anti-splatter spray wouldn't take care of. It is suppose to be
deeper penetrating but could cause thinner materials to get
too hot (so they say). I have used the CO2/argon regulator
on mine with no apparent problems, but I plan to buy the
correct regulator when I pick up my new MM 210 early next week.
I've always kept both bottles around so I could do either/

PJ

[Blown S-10]

thanx guys. what i would like = to be able to weld a little thicker and/or for more weld time per $. a tank the same basic size as my 80cf would be good.
a little spatter is not a consern.

lets see some pics of these tanks.

[hankj]

GunLocators,
The vapor pressure is actually <>830PSIA. What you see on the guage will depend on vapor space and temperature.

Hank

Blown S-10,

There are many sources for CO2 besides welding suppliers. Beverage and fire extiguisher service companies are certainly a couple of good ones. Places that seel beer kegerators have 'em too. The smallest I've seen is a five pound size, but I'd suggest you get a 20 just for convienience if nothing else.

Sorry, no picture!

Hank