This is the Gladius 3.0 Beta. Why beta? Well, this was my first try at using foam. I used camp pad foam that had big cells, and it didn't quite carve right. I didn't quite know what I was doing when I made this. I now have a good 3.0 release that's not beta, you might want to look at that. But the 3.0 Beta has a few qualities that are quite nice. For one, it's very bendy, so it's not likely to break any time soon. It packs a small sting when it hits someone, but it's not a lasting feeling, not for more then a second. It's a sturdy, but lightweight blade that's quite flexible, so what it doesn't have in looks it compensates with ability. It's a lot like a lightweight, flexible boffer. It's also the only sword I've made so far that has a safe-to-hit-with pommel.
1) A long circular wooden rod, about a quarter of an inch thick
2) Large celled foam camp pad
3) The sort of thin foam padding you'd find in a shipment box
4) Duct tape
5) Electrical tape
6) Foil tape
7) Double sided tape
If this isn't quite the type of sword you were looking for, I have 1.0s, 2.0s, and a better 3.0 that has very different qualities than this but still has the basic concept.
UPDATE: There is now an I'ble explaining my latest weapon making methods here