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@Mikenetic
Yesterday was mostly about seat stays. I also met Jambon, who dropped into the workshop to get some work done on a frame. I share space with Saffron Frameworks & Rusby Cycles.
First up was drilling gas relief holes, temporarily creating a sad robot face on the back of the seat tube. You have to give a path for air in the tube to escape, otherwise as you heat it the only path it has is through your brazing area. Do I want a braze with holes in it, or to be sprayed in the face with molten alloy? Nope nope nope.
Both stays were then tacked in place. The heat causes movement, so the top surface tack on the top lifted the bottom of the stay away from the dropout by about 1-2 cm. Once you tack the underside and hold it in position it locks back in. Amazing how much it moves, really.
Then the brazing of the stays was done in earnest. On the dropout end they need to be flowed into the existing braze, which involves reflowing some of that joint. The seat tube end is very tricky, as the gap between the stays is tiny.
Thoroughly preheating the area and working with gravity helps the braze flow through. I did have to reflow one small area, I think a blob of flux got in the way. No biggie. Rather than use a small No.2 torch tip for that I was advised to use a No.5. The extra heat output helps to quickly bring the small area up to brazing temperature.
It's important to be as neat and even as you can manage on the seat tube cluster, as it's a very awkward area to file. I did OK, but I did have to use some small jeweller's files called Rifflers to get right around the joint. Awkward, but satisfying to get right in there.
I made the error of not putting a dummy axle in the dropouts as a brazed, which caused the drops to pull towards each other by just over a millimetre. A quite firm push corrected that, and the back end alignment all looks good now.
Next week I'll refine the fillet shapes some more, then it's onto the brake bridge, chain stay bridge, seat post binder and the braze ons.