With Co2 it’s called MAG (_a_ctive gas) as opposed to MIG (_i_nert gas).
The CO2 will break apart at the temperatures reached, injecting carbon into the metal.

c02 as a shielding gas won’t give welds quite so pretty as using argon or argon/c02 mix. I really can’t imagine that tank would last too long.

What I’m not clear on is if he’s still using the flux-core wire, making it a dual-shield machine, or if he’s using regular wire.

The image of weld was a bit blurry, but it appears he’s still using the flux-core. He need’s to work on his trigger control though, that weld look’s pretty sloppy. Like it was choking and globbing up on the mating surface.

Sorry Rob, but that weld looks like what happens when I forget to turn on the shielding gas. I’m in no way a welder though, so keep trying.

This is a neat idea. You might want to combine it with this though

http://www.instructables.com/id/SpoolGun/

and weld off the beaten path with just a few batteries.

As for the paintball tank, it can last a useful amount of time because the gas is stored as a liquid. What really empties a CO2 tank in a hurry though is using it to drive air tools.

If you really want to get cheap CO2, the best way I’ve found is to buy used, expired CO2 fire extinguishers at auction or yard sales. Just make sure they’re still full and mount them sturdy upside down for gas. I’ve gotten an entire full CO2 tank and 15 lbs of CO2 for $15.

this is a cool proof of concept hack. im tempted to pick up a $90 flux welder from harbor freight and do the same thing, maybe with a better nozzle design and solenoid gas valve. (itd be really hard to weld in tight places with that piece sticking out)

a comparable sized CO2 tank lasts a LOT longer than other welding gases such as argon because its stored as liquid. its cheaper to have refilled too.

and not to nitpick, but i think he means COLLAR not COLLET. a collet is something else.

@Rob Tonight im gunna make a nozzle on the lathe and really do it up right

NICE! I was going to suggest using a lathe but didnt want to sound pretentious to those who dont have access to one. (i dont have access to one anymore) cant wait to see version 2

pretty crazy that they’re doing formula SAE in a shop with no MIG welder

Correct me if I’m wrong, but isn’t part of the point of having a flux core is that the flux volatilizes and creates its own protective vapor shield? If that’s the case, the additional gas would be nice but I’d bet it never gets near the arc.

http://en.wikipedia.org/wiki/Flux-cored_arc_welding

@scott:

Dual shield machines aren’t that uncommon. Flux cored welds aren’t that great, so the extra shielding certainly can’t hurt.

If someone is deciding between flux and MIG

If you want to do sheet steel or thin tubing, you should go MIG with argon or argon/co2. 110v OK

If you want to do up to 1/4 plate or a little bigger you can still go 110v but go with co2 as the shielding gas here will help the weld penetrate better. This is my main rig, a Lincoln 135 w/ mostly co2. but it does mix and fluxcore too.

If you want to save money, flux seems to work out cheaper per inch of weld. With no shielding gas bottles, hydrotests, or tank rental fees, flux core is used in production welding whenever possible, even realizing that you’ll have to chip off the slag. You also can’t do the really thin stuff

If you are learning to weld, get an auto-darkening helmet. They’re cheap nowadays and it will save you hours while picking up the needed base skills.

Ok, looks like he’s running way too much gas, also, angling the barb on the colette back towards the handle, so the gas doesn’t spew straight onto the weld would be preferable. also, he’s using innershield, which is a gasless wire.

I’m a boilermaker welder, you’re better off buying gasless wire. or stick.

stainless fluxcore will run CO2. helium is used for aluminium, usually 10/90 helium/argon or 70/30 helium/argon. the more helium the hotter the weld, but definitely dont use helium on metal other than ali.Argon is another weld shielding gas that could be used for general work, mostly mixed with CO2 or for tig purposes it’s used pure. much more expensive though.

Should have just bought a MIG welder in the first place – you can use flux core wire with most of those, just turn off the gas.

Also, you should be using a CO2/Argon mix – CO2 alone will comtaminate the welds.

Using flux core wire with gas is just an expensive waste.