I came across this at a website with other projects. Just scroll down to Recycle Plastic.
The basic idea is to build up sheets with an iron. The raw ingredient is dozens of plastic shopping bags. My only concern is that using the iron might be more costly on your electricity bill than if you went to a hardware store and bought a sheet of plastic. But I think it’s a novel idea and might lead to other things such as sealing things inside a plastic envelope to make them waterproof.
One thought comes to my mind. The plastic sheets are translucent, depending on color and thickness. These could be used as diffusers to spread out the light from point sources such as LEDs.
There are other projects on this webpage that you might find interesting.
