The blades seem to be made out of plastic. I thought about that too, but I'm not sure plastic can keep any kind of meaningful bend. Plastic in 1912, I doubt it, but they sure don't seem to be metal. I,ve got that much of it back together, but I'll take it back apart tomorrow because it looks like 2 blades could be shifted to make the stack a little tighter.. As I hold it up to the light I can see a little light leaking around when I turn the assembly to a sharp angle to the light bulb. I only originally had 3 of the six blades fall out and get mixed up. I suppouse I was bound to disassemble the shutter more than I really needed to, but sometimes you have to do that before you understand.