I have recently aquired a CO2 tank like this one.




Can I put argon gas in it or can I only use CO2?

 

For the official answer you would need to check with your local gas supplier. They may or may not fill it. Likely the pressure rating on the tank is not high enough if it is only for CO2. My Argon tanks comes filled to 2200-2400 psi. I think CO2 is well under 1000 psi.

 

the thing is that when you take it to a welding shop they will exchange it with a full one, so, you wont be able to keep that one, but yes you should be able to get a co2/argon mix or just straight argon in that size bottle

 

i got a 25/75 mix of argon/co2 and it was filled to around 2000-2200 psi

 

You'll have to check the tank and what PSI it can handle, then the valve will need to be changed, they will only fill it with CO2 otherwise.

 

Thanks for all the speedy answers!

 

The one thing that you are missing is that the CO2 when under pressure is a liquid. The pressure gauge won't move till most of the liquid is gone. If you put argon or an argon/CO2 mix in it, it will be a gas only and will not last any where near as long. So on a practical side its not really useful. Get a bigger cylinder for the argon.

I used a small welder with one of those small bottles..... had to get it filled almost every day.

 

What would the weld be like if it was only shielded with CO2?

 

CO2 will work, it runs hotter than argon or argon/CO2 mix and there is more splatter.

 

More splatter than flux? Would it even be worth it? I want to weld tube with it, so it might be too hot for that.

 

Never used CO2 only, but it is probably on-par with flux core, just no slag to chip off afterwards. For heat, just turn down the settings on the welder. When I first got my MM-175, I had an argon tank that I used. I found I had to run 1 setting higher than the book listed (e.g. had to use the 1/4" settings for 3/16" steel). Then got the Ar/CO2 and found the book settings were fine. I did notice more splatter with the 75/25 mix than with pure argon. The pure argon MIG welds looked almost like TIG, really pretty and clean.

 

What size welding bottle do you use for the argon? Do you still use the CO2 and argon mix, or did you go back to just argon? And why never use Co2 only?

 

Nozzle Dip. No need for Gas. PITA but thats how I weld.

Just gotta stop and dip every few seconds

 

I run the mix now, 80 cu.ft. bottle from the local welding shop. It was about $100 to buy then you just exchange it for a new one when empty. Gives me about 5-6 hours welding time and is still small enough to move around easily. I also have a 240 ft. argon bottle that came with my used TIG welder, it was set up mainly for aluminum. I like the Ar/CO2 mix best, cleaner than CO2 (a buddy used to run CO2 on his MIG, then switched to Ar/CO2 and said it was night a day difference) but hotter than Ar.

 

I've been using straight CO2 for several years - the tanks also serve as trail air. A full 20Lb tank will air up 25 to 30 35" MT/R's from 8 PSI to 22 PSI.

Welding wise, there is much, much less spatter than flux core, but 25 to 50% more than 75/25 mix depending on the welding position. Cost is less per tank too...