Wrap around wire ring

Hi,

Please can someone tell me how to make one of those wrap around wire
rings; it is one long piece of round wire wrapped around (manderel?)
randomly over and over again to form a ring made out of wire. How
does one keep the inside perfectly round? And how is this not too
soft to stay round? Do you only solder the ends? I am looking to make
it about 10mm wide when finshed. Can only find info on wrapping
stones. Please help.

Tracey