Question about gases

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I am new to welding and have a Hobart Handler 140.  I have been practicing with the flux core wire that came with it.  I want to start MIG welding, but buying the gas cylinder plus gas(argon/co2) is going to set me back $150 approx.  I am only doing this as a hobby so I am thinking about just getting some 100% co2....guy at Lowes said that had a 20 ounce bottle for $35.  Now I see in the Hobart manual that I can't use the gas regulator that came with the welder with co2.  Is this just an anal precaution on their part or can I still use this regulator?  Or should I just bite the bullet and get the tank cylinder for argon/co2?
Reply:Something you need to learn about welding.  Either do it right, or don't do it at all.  This goes for the equipment and consumables you use to accomplish the welding too.  Advanced processes (mig, tig, plasma) are not a poor mans hobby.  Get used to it, or use stick if you want to be cheap.A tiny 20oz CO2 doesn't last long and will mean multiple trips to get it filled, plus more money per lb of gas than with a larger cylinder.  If you're going with CO2, at least get a 20 lb cylinder, which probly isn't any less expensive than a 60cf bottle of argon/mix gas.  You can use the regulator, but it probly won't read correctly and you would need an adapter to connect it.  May as well get the right one and be done with it.MM350P/Python/Q300MM175/Q300DialarcHFHTP MIG200PowCon300SMHypertherm380ThermalArc185Purox oaF350CrewCab4x4LoadNGo utilitybedBobcat250XMT304/Optima/SpoolmaticSuitcase12RC/Q300Suitcase8RC/Q400Passport/Q300Smith op
Reply:CO2 bottles come with a different fitting, but you should be able to adapt something.CO2 is stored as a liquid under pressure in the bottle.  The regulator will NOT tell you how much is left (just like lp).  That can be measured in weight.  No, a paintball CO2 tank will not last too long, BUT, because it is liquid, you get more per volume than you would get from a similarly sized compressed gas tank.  That 20oz CO2 bottle would hold 11CF of CO2.A 20lb CO2 tank holds 175CF.  Compare that to a 60CF bottle (which is just about the same size as the 20lb CO2 tank)!I wouldn't recommend that you go with the paintball solution either though (because it's pretty small).  I would try to find a cheap and used CO2 fire extinguisher, and trade it in for a CO2 tank (even a 5lb tank would be ok).Option B, (which is what I do), is to get a paintball bottle, and a 20lb siphon CO2 tank, and a fill station (CO2 fill station adaptors are $40 or so on eBay), and refill that paintball tank as needed.
Reply:Unless you have a Millermatic Passport, there's no reason to have a tiny paintball cylinder for a welding machine.MM350P/Python/Q300MM175/Q300DialarcHFHTP MIG200PowCon300SMHypertherm380ThermalArc185Purox oaF350CrewCab4x4LoadNGo utilitybedBobcat250XMT304/Optima/SpoolmaticSuitcase12RC/Q300Suitcase8RC/Q400Passport/Q300Smith op
Reply:I agree with DesertRider33 on this one. Do not cheap out and try to do things half-assed. You mill be happier with the results of mixed gas over co2, especially if you are new to welding. co2 could be cheaper in certain situations, ( I run a big 50# cylinder of it at home) but by the time you buy the right adapter to use your regulator and figure out the correct flow rate and then freeze your regulator using co2, you are better off just getting the right gas in the first place. Also, bigger quantities of gas are cheaper per # as DesertRider33 said. Don't waste your time with a 20 oz. cylinder, you will be pissed when you have to go fill it up after a couple minutes of welding. Just get a tank of mixed gas, and go with one size bigger than you think you will need, because you will run out either way. Best of luck and I hope you enjoy your new hobby!IAMAW Local 330Airco 300 AC/DC HeliwelderAirco Dip-Pak 200 with Profax spool gunPowr-Kraft AC225Everlast PowerArc 200stBuffalo Forge No.21 drill pressSpeedglas 9100xxAirco, Oxweld, Purox, Victor torchesLincoln Ranger 8
Reply:Oh, and the cost of refilling that 20oz bottle at Lowes is about what I pay to have my 20 pound CO2 cylinder filled.
Reply:Thanks for being bluntly honest.  I went out and got a tank of 75%argon/25%co2 yesterday evening and I can't wait to start welding!
Reply:Great!  MM350P/Python/Q300MM175/Q300DialarcHFHTP MIG200PowCon300SMHypertherm380ThermalArc185Purox oaF350CrewCab4x4LoadNGo utilitybedBobcat250XMT304/Optima/SpoolmaticSuitcase12RC/Q300Suitcase8RC/Q400Passport/Q300Smith op
Reply:Bringing this back up - What fire extinguisher CANNOT be used to contain CO2?For example I found an old and empty Halon 1211 fire extinguisher - Can I get it cleaned up, refilled with CO2 and use that for mig welding?Hobart Handler 125 #500495Miller Diversion 165 #907005 (tig learning box)
Reply:I'll answer my own question since I went ahead and called around - As long as the tank is DOT 3AA-1800 stamped then it would be ok. Most Halon 1211 aren't and most places wont allow a straight exchange for a tank that's been converted.Last edited by TeckniX; 03-06-2012 at 03:23 PM.Hobart Handler 125 #500495Miller Diversion 165 #907005 (tig learning box)