Don't listen to Chuck the only welds I've ever seen of his were blobby and probably wouldnt hold under any real stress. Actually knowing what your doing is crucial if you want to rely on your welds to hold weight or if you are trusting your life with them in a cage like your talking about.
. It just takes practice, and a little guidance never hurt anyone. The best way to practice is to get some small pieces of metal (preferably the same thickness you're going to use on the project), weld them together, and then use a BFH to break them apart. It will give you a good idea of how strong your welds are, plus you can look at the penetration of the weld. At least that's the way I did it in my Farm Mech class in Clemson.