Another material I've used in many of the IAC mods, is clear box tape. The kind used to seal up packages, that comes in those plastic dispenser frame things with the cutting edge. Epoxy won't stick to the non-sticky side. I've sometimes doubled itself sticky side to sticky side, to make it more rigid. You then find a place to stick it on w/ more tape.
Like Ron said here, plastic, like the energy drink bottle you used, works well when making a form or dam to sit in the throttle bore. This mod makes me really creative. I've used business card stock too. Whatever is used, if you doubt if the epoxy might stick to it, just put clear box tape on the surface that faces where epoxy will go. works every time for me!
cheers!
Tracy G