To make a 3mm sterling silver wire rigid enough to be considered
rod, draw your wire as usual, then clamp one end of it in a vise, and
using a hand operated drill, twist the wire until one end snaps off.
The formally curved wire will become very straight and hard.
(Clean up the barber-pole stripes using 320 grit sandpaper followed
by 1500 grit paper. And discover if you turned down the rolling mill
jaws too fast.)