First I filed some wooden frame blocks and squashed the chainstays a little bit in a vise. No pictures of this, but you all would probably cringe. It's fine. I know where the limits are, having seen an old frenemy/Vermont framebuilder exceed them in the past. It fits a 650x42 tire now.
Next spreading the frame. Why do Americans call it cold-setting? So pretentious and exclusive sounding. I dunno about you, but I spread things. I don't cold set them like some kind of materials scientist. It is 135mm now. I aligned the dropouts with an adjustable wrench.
Now onto the most controversial thing.
Some folks like to spread rumors on the internet. Some of these folks think they know what they're talking about, think they're telling the truth. But they don't get out enough. And it's bad for the community. Bike guys say it's not possible to bronze braze without oxy. Tractor guys say it is possible. Who is right? The temps look hot enough. The question is not of peak temperature but of how much heat can you dump into the part before it gets dissipated. Only one way to find out.
So I tried it. I'm using MAPP/air, in a
turbo torch from Amazon that I normally use for HVAC stuff. I have oxy acetylene and I have oxy propane (just hook up your oxy acetylene torch to your BBQ tank, the pressures are a lil hard to balance but you can do it). I like oxy/pro for cutting. I like oxy/ace for gas welding (but TIG and even stick are way easier) and flame-hardening. But I also unfortunately have terrible neighbors. Neighbor Gilles told me I was abusing him because I fixed a hole in a kevlar canoe in the backyard which also contained his tomato plants (how does he think kevlar will get into his tomatoes? Does he really think my canoe is water soluble?), so I'm trying to do this stuff at the machine shop at work where people don't care how abusive my hobbies are. Unfortunately, oxy isn't allowed in the machine shop. So turbotorch it is.
I'm using
Gasflux type B flux and
Gasflux C-04 nickel bronze rod from Framebuilder Supply. The jig is made from science scrap, but any scrap will do, really. My buddy Will way overbuilt it, but we had fun and it was nice to use and maybe I'll keep it.
Clearly it works. I had the torch just roaring, all the way on, to dump a lot of heat into the cantilever post (why do they call them bosses? Again, too fancy. My boss tells me what to do, she has nothing to do with stopping my bike, I hope). Add filler, then just drew the flame ever so slightly onto the tube, to get it to wet. Add more filler and done quickly. I probably could have tig welded them, but I didn't want to tig 531 and tig is not C&V (wait for me to contradict myself when making decaleurs). Call me superstitious, but it felt weird to think about welding things to a brazed bike.
The posts are like 84mm apart, which I know is a smidge wide. What can ya do. That's where the frame was, and I wasn't about to do some custom cantilever posts. It's a rear brake so I'm not worried about it.
Next week I'll do the fork.