When you can practice on your own stuff then this type of project isn't any big deal but when it's for a customer then the game changes. A little advice for you...if you cut out the top of a keg for someone, don't throw the cut-out away, save it in case you have to make a patch if you ever do make a mistake. I welded a patch piece onto a keg to cover a hole where I removed a fitting that someone else butchered onto the keg that the owner didn't want. There is good money in welding for home brewers because most of them don't know any Tig weldors. These brewers tend to run in packs so if you can locate a brewers club and offer your services then you can pick up some cash. You won't make a living at it but your name gets out there and suddenly you will get a bunch of calls about fixing all kinds of things. I know guys that weld for a living but they don't do off-the-wall stuff like kegs or aluminum or Tig brazing (which I have never gotten a call for). I just finished a piece for a friend of mine who is a union boilermaker. It was a bit for a jack-hammer that they needed modified. I asked him why they brought it to me because they are all weldors, and he told me that they didn't have a WPS so none of them knew what to do with the thing I told him since I wasn't sure about the metals composition, that I would use Supermissle to weld it and he had a blank stare because he had no idea what Supermissle was. I am no welding hero but my point is, doing specialty welding can get you some easy cash. I pocketed $100 bucks from the company my buddy worked at for about 10 minutes of welding. You will never get rich or they will never write songs about you but I get a good feeling inside when people bring ne weird shit that no one else wants to be bothered with. Hang around and send us some more pics on your projects, there are some world class weldors that hang around here and no egos so you are in good company!
ps...Steve aka Ottoknowbetter is a walking encyclopedia and he will answer any questions you have
I used the top I cut out for all of my practice I did that with a plasma which I had read was not the way to go (I think it was from people without plasma cutters). I made a jig and it came out perfectly.
I was taught by nuclear and aircraft certified welders so I know quality work when I see it and there are indeed some amazing folks on this board. I agree that the atmosphere is great here. Not a bunch of egos or trolls.
I weld mostly in support of artwork (I am an amateur glassblower) or the occasional functional project (I'm building an aluminum recumbent bicycle). I'll definitely be back.
I continue to learn even though I've been welding for some time both from Jody's videos and folks here.
Plasma is the ONLY way to go when cutting a keg top out. Watch some of the vids on Youtube with those poor souls trying to cut one open with a cutting wheel or a sawzall...the hard road uphill if you ask me. You just need to aware of the hexavalent chromium when you cut it. Do it outdoors if possible and wear a respirator or at least keep your head out of the smoke. I made a jig for my plasma torch that rides inside the keg lip and cuts a perfect circle every time. Then just take a grinder to the cut to take off the sharp metal. You will have sugaring under the cut but I just grind it off.
I don't do metal art but I just got back into making my own furniture as I bought into an artisan shop and my stuff is selling. Glass blowing is badass...I know I don't have the patience for it but I would like to try it. I do stained glass when things get slow. I design my own patterns and I put some of them in the artisan shop and they are selling. I could dig staying home and welding, making furniture, stained glass panels and drinking beer every day
I filled it with water before I cut it. I was outside, but there was no visible smoke and just had to dump out the water instead of scrubbing the inside. I also used a 20 Amp drag tip (Cutmaster 42) and cut at low amps which makes a tiny kerf and no sugaring.
I told him since I wasn't sure about the metals composition, that I would use Supermissle to weld it and he had a blank stare because he had no idea what Supermissle was. I am no welding hero but my point is, doing specialty welding can get you some easy cash. I pocketed $100 bucks from the company my buddy worked at for about 10 minutes of welding. You will never get rich or they will never write songs about you but I get a good feeling inside when people bring ne weird shit that no one else wants to be bothered with. Hang around and send us some more pics on your projects, there are some world class weldors that hang around here and no egos so you are in good company! 
I did that with a plasma which I had read was not the way to go (I think it was from people without plasma cutters). I made a jig and it came out perfectly.