Check the back of your machine and see if there is a fitting which might have a plastic cap on it. If it does have a fitting you will need a bottle, regulator and short piece of hose. If there is a fitting then most likely your current gun/cable will transmit the gas thru a nozzle where the contact tip threads in.
Good luck
Neal
Hello,
If your welder was being advertised as a MIG welder, and the manual makes no mention of an extra line, then it will almost certainly already have the gas line fed in. If your welder needed a line putting in to the torch it would have been advertised as being a wire or gas-less welder most proberly. Have a look on the very back of the welder itself and look for a hole or piece of plastic tubing that will carry the gas, it might be wound up inside to save space. If it's designed for the mini-lecture bottle jobs it'll have a ledge for the bottle to sit on, don't ask me why though because they just fall off or slide around no matter how many cable ties you use (Bottles have a rounded base). The gas gets to the torch because inside your gun there is, as well as the electrode and wire feed switch, a gas valve you open by squeezing the trigger. The gas goes through a real cheap flow regulator, that goes with the mini bottles (Which'll last about 15 mins max each), through the welder and up to the gun. When you start welding it flows out to the tip and leaves through some holes in the bit that is holding the electrode, if you unscrew the cap you'll see them. I'm not sure if my, very cheap, welder has been designed like this but I find if you just gently squeeze the trigger you can fill the cup with gas which I assume will make some difference. I've taken to doing it every time now just before I start each weld, with the gun to the work so as not to blow it away as you move into place. I'm sure you'll notice a very big difference in the way the weld looks with the gas instead. If you're going to do a lot buy a nice big cylinder and some protector to spray over the gun to stop it getting mucky so fast, I'd clean it out after your done welding each day with some kitchen roll or something. Good luck with MIG anyway, I'm new to oxyfuel welding and it's just as hard, if not more, than MIG. You proberly won't need any help but if you ask someone who can MIG weld already you'll pick it up in a few days atmost. I taught my brother and it only took him a night to make some welds that looked reasonable. It took me more like a few months to work it all out by myself.
John