Originally Posted by bulgie

If you mean the "Nickel Silver", that's not solder, it is brazing filler, similar to brass (a.k.a. bronze) but slightly higher temperature and quite a bit stronger.

Yes the "silver" in the name is a misnomer, don't know how that got started, but it goes way back.

One common use for it is repairs on gears with broken teeth. Blob on some nickel braze, then shape the new tooth however you like, even hand-filing if you're good with a file. It's often as strong as the original steel tooth.

I made my first lugless frame for myself in '77 using nickel-silver for the fillets. Naive 19 y.o., I just looked at the chart and picked the one with the highest strength. It was a PITA to file the fillets. They are harder than brass, and kinda slippery, so the file wants to skate off. Not recommended! Brass, such as LFB or C-04, is plenty strong enough as we know, unless your fillets are microscopic, so there's no need for a stronger filler there. If you use it for fillet brazing, plan on laying down clean fillets and leaving them in the as-brazed condition.

You can make use of the higher solidus temperature though, for example putting seatstay caps on with nickel, and then brazing the stay to the lug with brass, without re-melting the cap's braze.

Uses the same flux as for brass/LFB.

Mark B