I've had an idea for a while of building a set of planar magnetic headphones, completely from scratch, partly to see if I can make something good but mostly for the fun of it. One thing that is really holding me up is finding the things I would need - in particular reasonably thin metalized mylar. The best I've been able to find that is sold in small quantities is 2 inch wide, 2.5mm (~1/10inch) thick tape, but based mostly on looking at plastic films that thick, I expect it would make a terrible diaphragm.
Does anyone know where I could find a very thin sheet of metalized mylar? preferably in NZ or Australia, but if it's good and has a good price I'd be prepared to import.
Also, I don't really know too much about the etching process. From what I understand standard process would be to mask out what you want to keep, then imerse in an etchant (I've heard that the standard is 0.1mol/L FeCl3(aq)). Would this work? What could I use as a mask? Is there anything else I should know about etching (besides standard lab safety for handeling chemicals)?
If what I want can't be had, what other options are there?
I don't want to go half-assed on this project, so I'd rather not go with things like gluing Al foil to cling film, unless that actually makes a good diaphragm. Basically when I'm finished I either want a good set of headphones, or I want to know that they sound bad because my design/build was bad. I don't want to be left thinking that I could have made something good if I hadn't cheaped out on materials, although at the same time I am by no means able to spend stupid amounts on this.
Thanks in advance for your response.