How much Shield Gas?

I bought a 20lb Co2 for MIG and a 60CF argon tank for TIG. These are relatively small cylinders, about 2-1/2 feet tall 40-ish pounds but I need to move my cart a fair distance to do any welding and didn't want to deal with large heavy cylinders. My local gas supply is easy to work with and only about 15 minutes away. Since they are small I could easily fit both cylinders in the car if for some reason the truck was unavailable.

A 20lb Co2 is approximately 175cuft, so with a small MIG welder 5 or 6 hours of continuous welding. Co2 is much cheaper than the Co2 argon blends. You do get a volume discount on larger cylinders, but will also have to make a larger purchase (less frequently) when you do fill up.
 
Thanks everyone for the input. I am thinking that the #3 is the right balance between size and convenience. I expect that over time, I will get a second bottle and or a bigger one.

I also expect I will be back here with other questions :)
 
you can never have a large enough tank as far as i'm concerned :grin:
i get the largest trimix cylinders, i think they are 225 cuft, if i'm not mistaken
i get the next size smaller for Argon, and the next size down for 75/25
 
Maybe start with a small spool of flux core, so you don't burn up any gas. Figuring out heat range, and wire feed will take practice, there should be a decal on the machine that will get you close, and you will need to bump the settings to fine tune. The better the sizzle the less splatter, and try to get as clean a surface as possible.
 
I only TIG weld but it seems like I am always running out of gas. I believe that I have a 160-ish cu ft tank.

As far as gas vs nozzle sizes.... A number 5 nozzle you should run 10 CFH gas. Number 7 nozzle would be 14 CFH. I just figured this out a little bit ago by watching the Fabrication Series >>>Fabrication Series Linky Here<<<. Up until that point I had been wasting a ton of gas by running 20 to 25 CFH. Only time you would need to turn it up is if it is windy or something unusual like that.
 
Boswell said:
Thanks everyone for the input. I am thinking that the #3 is the right balance between size and convenience. I expect that over time, I will get a second bottle and or a bigger one.

I also expect I will be back here with other questions :)
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@Boswell, if you don’t already have a welding shop to deal with, the guys at Round Rock Welding Supply are the best in the Austin area, and closest to us. Based on my experience, of course.
 
All my tanks are Q(80cf), in my area they're the biggest I can own and they're small enough to haul in the car. Gives you about 4 hours of working.
And given the earlier reference to Murphy's law of after hours empty tanks, I set all the welders up to hold a second tank, except the small portable mig. I'd highly recommend a second tank instead of one large one, regardless of how careful you are eventually you're going to leave the valve open & forget and no matter how tight your system, it'll be empty, a second tank will save your sanity (and your bacon)!
 
a second tank sounds like good advice

thx
 
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