Framebuilders - brass or nickel/silver?

so... who uses nickel silver versus brass versus silicon bronze for joining CrMo? anybody use a flux-injecting torch?

Based on what I've heard (and read) from Fred Parr, nickel silver is good for some small stuff (bridges, etc) but is very hard to make into a large fillet that isn't brittle- so I've stayed away from it and stuck with brass or 56% for lugs.

I exclusively use a gas fluxer - they do wonders for the quality of a filet joint.

My choice is low fuming bronze only for filets and silver solder or bronze for lugs. I have experimented with nickel-brass for some stainless applications but no serious work.

Based on what I've heard (and read) from Fred Parr, nickel silver is good for some small stuff (bridges, etc) but is very hard to make into a large fillet that isn't brittle- so I've stayed away from it and stuck with brass or 56% for lugs.

Nickle/silver is not silver at all, it's for building fillets.

56% silver is the stuff for small stuff and/or lugs.

My local store sells 46% silver that I have been using to put together racks. Can it be used for fillets on bike sized tubes? I gather it can be used for lugs and braze on bits.

Thanks Don. I'm not having that problem at all, but these tiny rack tubes don't hold much heat so perhaps that makes it controalble. I was wondering about the larger scale stuff. Where yo using the 56% stuff in your silver days?

i've looked into gasflux, the only thing i don't like about the system is that it can't be turned on and off on demand. maybe i can build a flux injection system using a powder torch valve... hmmm.

i've also been practicing with silicon bronze and tig. excellent control and tons of strength. it's just like brazing with a tig torch, the base metal is not melted. you can go back over the silicon bronze joint to smooth it out like a small fillet, so it is not a true tig weld. far less heat spread compared to brazing.

I assume you have to use a flux? And also argon gas with the tig torch? I tried that once, but I got a bad result, not surprising I socked way to much heat at it. I havent returned to try it since hearing I needed very light amps, what do you set yours at?

I assume you have to use a flux? And also argon gas with the tig torch? I tried that once, but I got a bad result, not surprising I socked way to much heat at it. I havent returned to try it since hearing I needed very light amps, what do you set yours at?

really low, just crack the throttle enough to hold a stable arc. 3/32" thoriated tungsten is the heaviest you would want, 1/16" would be better for light tubing. no flux, just bare silicon bronze rod and argon. you can see the base metal heat up, it is okay to let it melt a little bit, but you do not want to fuse it or let a puddle form. just strike an arc and begin dipping filler metal into the arc. the process with silicon bronze is a lot like brazing, but much faster and more controllable.

tensile strengths
silicon bronze - 55,000 psi
nickel silver - 34,000 psi
yellow brass 80/20 - 13,500 psi