For my own quirky reasons, I wanted to make an honest condenser mic like they did in the 1930s (just not as good, I'm sure).

My basic idea is to use a sheet of aluminum foil or aluminized mylar hanging about 1mm* from the large pad on the PCB.

Foil is fine because I know it's conductive, but I can imagine the problems I'd run into trying to stretch it to the frame as it's fragile.

The mechanical properties of aluminized mylar are good, but I'm not sure if a typical aluminized mylar on a space blanket or balloon will have a continuous sheet of aluminum, or if there is enough aluminum to make it shine.

so:
Does anyone know if "typical" (in the sense if it's mirror bright on one side) aluminized mylar is conductive?
If this "typical" thing can't be expected to be conductive, does anyone know the right keywords to search for something that gets? A brief google search didn't help me, but I'm perfectly capable of having a really bad Google endowment.