This instructable will show you how to make robust versions of Link's sword, a scabbard, replicas of his wooden shields, and fully functional slingshots. While this stuff is all part of a costume, it's also all quite tough enough to handle being bashed, scraped and abused in the course of a usual day's play.
Note: this instructable is four projects in one, so if I've blasted past something too quickly, post a question in the comments.
Step 1: Design
* if you want to know how to make an awesome replica, see Jonny1983's beautiful hand-tooled wooden version.