Tig fillet brazing has long been an interest of mine. I used to paint John Cherry frames and he gave me some filler rod to try many years ago. I don't know what rod he gave me. We went to the very 1st titanium tig welding class together UBI offered in the early 90's. Anyway I got awesome results with a very consistent and even fillet pattern. The fillet was a bit smaller than what I usually do with a brazing torch although I liked that look just fine. The problem was that the joint had no strength. I could break the tubes apart without having to use super strength. I've never been ambitious enough to study what other kinds of filler rod could be tig brazed. However what rod I used would work just fine as a cosmetic filler over a joint already welded. Whatever I had was a low temperature melting rod.