Lord of the Rings, positive, behind the scenes [2]
Also: the chainmail loops were made from an industrial hose, which was light and made of plastic, but it looked like real metal, which meant the actors could wear the chainmail without it being super heavy.
Also also: every sword was made 4 times - once as a real sword, then once as a "scale sword", for doing the whole "hobbits are small" thing, then again as a rubber safety sword, then again as a liteweight sword for the fast action scenes.