Acutally Kydex is a manufacturer of PVC and Acrylic mixes of plastics. They have a whole range of plastics for sale and most people have called the sheet PVC plastic (may have acrylic in it also) as the name of a particular type of the plastic. The other thing that the astro community is looking at is the knobby appearance of the material. Actually what you want is a black PVC sheet for what you are doing and the much cheaper stuff that you can get. Personally, I`d rather get some doorskin plywood and soak it for a day or two and then put it in a steaming box and bend that to the right contour. A drum of some kind is the best thing to wrap it with and use strips of rubber from a tire inner tube for the rubber band.