[nathan]

I got an aluminum CO2 tank on a trade for my last job. It is made of aluminum and says "20#CO2" on it with some date stamps that I don't know how to read and other markings. Will this work with a welder and welding regulator? I have only ever used steel bottles.
It seems to have been made for home brewing, as that is the listed purpose for all the tanks in a quick Google search.

[hey_allen]

I know that pure CO2 can be used in MIG welding on steel, but it isn't as pretty as 25% CO2, 75% Argon. It seems to burn a bit hotter and deeper, and spatters more.
That said, if you don't mind the deeper penetration and some spatter, it is a cheap way to shield when welding mild steel.

I have a 5# bottle that I intended to use for MIG shield gas, but haven't actually run on my machine yet. It has been useful when running air tools when away from my compressor, though!

Other than that application, I don't know where else it could be used in welding. You might just trade it toward a bottle of your choice at your local welding supply/gas shop, or sell it and buy the bottle you want?

[MinnesotaDave]

Yes, a 20lb co2 tank can be used for mig welding.
It's approximately 170-180 cubic feet of shielding gas.

I have two of them, one steel, one aluminum.

Most regulators need a small adaptor to hook on to a co2 tank.
Like this one:
http://www.ebay.com/itm/CGA-320-to-CGA- ... 20fa55a3d5

Or you can use this HTP flowmeter, it has the right hookup already on it.
http://www.ebay.com/itm/Argon-CO2-Regul ... 2353979049

[Braehill]

Nathan,
This should help clear up what all the markings on the cylinder mean.

http://www.phmsa.dot.gov/pv_obj_cache/p ... inders.pdf

Len

[nathan]

Thanks, y'all! This is really encouraging! I understand that inert shielding gasses all use the same steel bottles, I wonder if the same is true for aluminum cylinders. I want to use more argon than co2. Although, it would be neat to do some dual shield fcaw if I got a gas solenoid for my little Lincoln 125.

[Artie F. Emm]

I understand that inert shielding gasses all use the same steel bottles, I wonder if the same is true for aluminum cylinders.

Different types of bottles have different types of valves: inert gases (nitrogen, argon, argon/co2 mixes, helium) use the same type of >valve<, called a CGA 580. The reason for different valves is to avoid accidentally delivering nitrogen instead of oxygen to a hospital, for instance. (I heard a story how this happened.) CGA 580 valves can come on both steel and aluminum cylinders.

I want to use more argon than co2.

Do you mean you want to use a blend of Ar/CO2 MIG shielding gas? If yes you'll need to get it from the LWS, because you can't blend it yourself (unless you have gas blending equipment).

Just a heads-up: I've seen many aluminum co2 bottles for sale on Craig's List, and many of those are owned by Coke or Pepsi and illegally sold. They are often 20# size, made of aluminum with a plastic handle / shroud around the valve. If they are stamped with "coca cola" or "pepsi" the LWS will not fill them or take them in exchange.

[nathan]

Thanks for the heads up! I will check for a stamp.

What I meant was that I want to do more tig work than anything else. Sorry for being unclear, that was the last thing I typed before bed this morning lol

That is really interesting about the valve, I can see how that could be a problem at hospitals.

[Otto Nobedder]

Nathan,

For TIG work, CO2 is an "iffy" backing gas at best. It will NOT work as a shielding gas.

I may be stating the obvious, but the way you worded your last post I had to mention it.

Steve S

[nathan]

Damnit.

I'm about as clear as mud lately.
CAN I GET THIS BOTTLE FILLED WITH ARGON, OR CAN I EXCHANGE IT FOR ANOTHER THAT IS FULL OF ARGON? lol (caps for clarity. I promise I'm not e-screaming)

[rick9345]

Ask your LWS, a lot depends on the relationship with person behind the counter. Doughnuts and and small purchases of over counter supplies(never compare internet prices to his) works wonders with mine.
Since I am not a big bulk account I have to be nice in other ways.

[Braehill]

Nathan,
The short answer is no. The cylinder made for CO2 is different than a cylinder made for inert gas, Argon, Nitrogen, Argon/Co2 mixes.

The answer to the second part of the question depends as Rick said on your local cylinder fill. If the cylinder is still within retest date they may trade you for a inert cylinder or may not. If it's out of recertification test date they will probably charge you for the test in addition to the trade.

It takes awhile to build a relationship with a local welding supply before they will trust that you're not trying to rip them off by bringing them stolen cylinders to be filled. Most people don't have a bill of sale for their cylinders or have cylinders that have years of rental fees due on them. If the cylinder fill takes these cylinders in on trade they have a responsibility to get them back to their rightful owner, thus being out the cylinder they gave you.

Any cylinder over a certain size is probably not owned, but leased from a cylinder fill company or a large company like, as was mentioned, Coke or Pepsi, etc.

You'll only know by taking it to your local cylinder fill to find out. Your best chance of a good outcome is to go to an independent company that fills cylinders, i.e. not Airgas, Praxair, Linde or the like.

Len

[nathan]

Awesome! Thanks a ton, guys!
Looks like I will keep it as CO2 and get another bottle for argon when money rolls around. I'll work on setting up a solenoid on my little Lincoln so I can do mig and dual shield. Dual shield sounds exciting. Oh, the penetration and smoothness!

[MinnesotaDave]

Awesome! Thanks a ton, guys!
Looks like I will keep it as CO2 and get another bottle for argon when money rolls around. I'll work on setting up a solenoid on my little Lincoln so I can do mig and dual shield. Dual shield sounds exciting. Oh, the penetration and smoothness!

I don't think you'll be running much outershield/dual shield with a lincoln 125.

Many of the wires start at the top of your amp range.

Hobart fabshield 21b has listings that would work on your machine, but it's much more expensive than running regular solid wire and 100% co2.

[nathan]

It won't help the self shielded wire to throw some CO2 on it? I think I'm making myself sound like an idiot here lol. I promise I'm not an incompetent nincompoop.

I know you can't run dual shield without gas, but I thought you could use normal FC wire with gas.

[Otto Nobedder]

I know you can't run dual shield without gas, but I thought you could use normal FC wire with gas.

You can, but to what end? To expend gas you didn't need?

There may be a benefit; There may not. The wire was designed to self-shield to exclude atmosphere, so it should not care at all what atmosphere it's excluding.

Steve S

[MinnesotaDave]

I know you can't run dual shield without gas, but I thought you could use normal FC wire with gas.

You can, but to what end? To expend gas you didn't need?

There may be a benefit; There may not. The wire was designed to self-shield to exclude atmosphere, so it should not care at all what atmosphere it's excluding.

Steve S

Steve is right - not needed and detrimental.

From Lincoln:

Not only is the use of any type of shielding gas not necessary for Innershield® NR-212, or any other type of self-shielded, flux-cored electrode (FCAW-S), it should not be used. FCAW-S (i.e. Innershield®) electrodes have a tightly controlled and unique core composition and interaction with the atmosphere (compared to gas-shielded, flux-cored wires). They rely on the oxidizing effect of air to produce the desired weld deposit and desired resulting mechanical properties. When you use a shielding gas, you block the arc from the air and prevent the oxidizing reactions. This results in a much higher level of alloys, such as aluminum, in the weld metal, which produces a brittle and crack sensitive weld deposit. While it is likely that the shielding gas improves the stability and operator appeal of NR-212, it also results in an unacceptable weld deposit.

[Otto Nobedder]

Thanks, Dave,

I hadn't considered the idea that standard atmosphere was a critical component in the self-shielding. I was only looking at "exclusion", and didn't consider "inclusion".

Great info!

Steve S

[nathan]

Thanks a lot, I thought this would be a simple thing, but there's a lot to it. I'm glad I asked instead of just doing it.

[MinnesotaDave]

No problem Steve, I find it pretty interesting too

Hey Nathan - welding is only simple until you actually do it