Can I anneal these lengths with a small butane torch?
Yes, I routinely do this with a water torch despite it having a
small, very hot and concentrated, flame that cannot be made bushy. I
use the coolest part of the flame and am careful not to keep it
still. I wave it back and forth over the wire until it reaches the
correct temperature. If you make a little bundle of short lengths
tied up with binding wire it is much easier to anneal the bundle than
a single piece of wire.
Make sure you follow the correct quenching proceduRe: some alloys
must not be quenched, some must be allowed to cool to black heat
before being quenched, and some must be quenched whilst still glowing
a little. Don’t quench in pickle whilst still tied with iron binding
Regards, Gary Wooding