Here is a Extralite I’m building. I realized when building it, I think the hardest thing I routinely do is weld those super thin seatstay tops. They are .5mm (0.019″) and in addition to being incredibly thin they are very hard to get around because of torch access and visibility. I’ve done enough of them that they come out right every time but I still find myself holding my breath when I weld them. I used to braze them because it was easier but we found that with brass you could get some micro-cracks next to the web of material between the stays. My guess is that ‘s it’s caused by the different rates of contraction between the tube and the brazing material. We used silver and had better luck but I think it’ s best to just bite the bullet and weld them. It’s harder to do but I think ultimately you end up with a better result.