All my Canon FD hoods were plastic, but maybe they made metal ones in the earlier days. I have bought metal screwmount hoods inexpensively off eBay from Asia and India. The ones from Hong Kong were better made than the Indian ones, but there were some sizes from the Indian shop that weren't available from the Hong Kong dealers. There's another dealer on eBay--"Lim's" if I remember correctly--who sells aluminum hoods for some of the big Canon teles.