The Focus Fusion Society › Forums › Lawrenceville Plasma Physics Experiment (LPPX) › i just don't understand the mylar › Reply To: Regulations on Independant Experimentation with Focus Fusion and Sonofusion type Reactors
http://www.dupont.com/products-and-services/membranes-films/polyimide-films.html
Kapton would be a far better choice than PET.
I’m pretty sure that a terrific company like DuPont would donate all the film you need.