I suppose you could wrap it around a mandrel and smack it with a rawhide or leather covered mallet, but using an arbor or hydraulic press is much easier and less likely to harm the engraving.
Most of our bracelet formers use Delrin, urethane or both in combination... for example - we have a ball shaped piece of Delrin on the end of an "L". This ball shape presses from the inside of the bracelet. The outside of the bracelet (where the engraving is) is cushioned by the urethane. You work your way down the length of the bracelet, curving and doming as you go. This can be done with either the arbor or the hydraulic press.
Another method, which is a bit more complicated - uses a 2 piece Delrin die held together by retaining rings. The bracelet is rolled up and put inside the die and then a round section of urethane about half again as tall as the bracelet is put in the center. The whole assembly goes into the hydraulic press and the round section of urethane is squashed - pressing the bracelet outwards and into the concave cavity machined into the Delrin rings. The die is removed from the press, the retaining rings knocked off, the two part die opens and the finished, domed and curved bracelet falls out...
Then there are "H" frame bracelet benders. The "H" is mounted by the two bottom legs to one end of a hardwood 2" x 4" so that it pivots. The center of the "H" has a 2" or bigger "bead" on it. The bead can be made of brass, aluminum, steel, Delrin, or whatever's handy. The hardwood has a carved depression right under where the bead meets the surface. Weld or bolt a bar across the top of the "H" for your handle. Put the bracelet blank lengthwise (engraving side down) on the wood and start pressing.
You may have to build this gadget pretty stout - depending on the gauge of material you have to form. You simply press and move along, press again - until the blank has acquired an even dome and has rolled up into more or less the form of a bracelet...
Kinda hard to describe some of this in a way that you might all understand...
I can think of about 5 other ways to form bracelets without damaging the engraving, but I have to get back to my chores.
Besides, I TEACH this stuff - come take a workshop and learn how to make dies, cut, and form lots of other stuff - not just bracelets!
Brian P. Marshall
Stockton Jewelry Arts School
Stockton, CA USA
209-477-0550
instructor@jewelryartschool.com
Two last tips - don't forget that, unless you are using hydraulic press (and even then, most times) - you MUST anneal the material to be formed! Dead soft!
IJS used to sell a bracelet domer that you hammered into a wood block. Crude, but it works if you're careful and cover the steel with leather. Easiest tool to make yourself...