Just catching up or I'd have responded sooner. My apologies if this
has already been suggested.
I use a shallow half-round stock (a little wider than the desired
width of the finished band), but form the band with the dome to the
inside. You have to really force the metal into shape this way -
you're working against the thickest part. When the ring has been made
and soldered to size, you can work away that edge, yet retain the
inner dome and total thickness. I like to make ring shanks this way.
It also occurs to me that forming the band with round wire and then
planishing and filing to achieve the final shape would work as well.
Haven't tried it though. I'd want to start with a ring in a size
smaller than the final size.
At the end of the day, it's easier to order a "comfort fit" band
ready-made... probably less expensive too. (Stuller stocks a good
variety of dimensions - no association, just a satisfied customer)
Judy in Kansas