shrink plastic questions

[sotoalboroto.livejournal.com]

hi there. i've been googling and reading for some time now, but i thought i'd ask here to see if someone already knows the answers to my questions.

i'd like to make a ring and a bangle out of shrink plastic. how do i curve it to fit properly? if you have any links or suggestions, i'd appreciate it. i guess this is the same principle as curved napkin rings, but i haven't found anything specific on those either.