personally i find welding chains, and cable to be fairly simple if you prep everything properly, and Ive never welded anything in a can, with any kind of powder. it's not really that difficult even with used materials, just gotta clean them right, and take your time. but not every body is capable of doing the things that others do as easily. me i have had very few problems in the ways of welding, but getting my grinds nice , even, and flat has and still is giving me one hell of a time.
i will agree that to start with a simple billet may be more successful, take your self about a 15'' piece of 10xx series steel, and some saw blade. cut it like you were gonna fold it like an accordion maybe be every 3'', then get it hot, and fold back about 3'' of the 10xx, and slide a piece of saw blade in, and weld, then do it again fold back at your next cut and slide in another piece of saw blade, and weld. do this until your left with just about a 3'' long billet, draw it out , fold, then simply flatten and grind or forge out a blade. you'll have a very low layer count billet but regardless it's still damascus. im no expert by any means, but this is worked for me when i started welding.
PS. my hats off to all you grinding experts, grinding them blade makes me crazy, a screw up 2 of every 3 !!