Hey, BC- I`ve made several in the last three years and am working on number six currently. Since I was already a so-so TIG welder and really hadn`t brazed any to speak of, I welded the first three, then learned to braze and I like the results much better. Structurally, I`m sure the welded ones are fine, but cosmetics are way better since I started brazing them. A lot of it has to do with needing to weld around such a tiny radius like you have to for small tubing and some also has to do with the stuff you already have in place getting in the way of the torch or filler. Like I say, I`m only a so-so TIG welder, so your results might very well be nicer than mine. One advantage TIG does have over brazing is that it`s easier to put stuff on the bike and tack (without burning paint, cables, tires, etc) it with a TIG torch than with OA.
One of the things I figured out that might help you is to build the platform first, then the overlength "legs", then clamp the platform to the bike however you can and cut the legs to fit and miter them. I did the first few by starting from the attachment points and working away, which still kind of makes sense, but turned out to be harder. Most of mine were commuter and grocery type racks that probably have much bigger platforms than you`re thinking about for touring, but I`ll get some pics this weekend to show how I`ve been handling the "crotch" of the legs and the other mounting points. In the mean time, here`s the slickest looking touring rack I`ve seen. It was posted by a guy on bikeforums, built by his buddy, I think:
http://www.bicyclesmile.com/
