Glad yah like it :] Looked through your gallery and you've got some really neat stuff yourself there!
Yes, you may...
But seriously, my answer might be kinda dull here, but if there's anything, just ask me again:
Foam.
The blade is made out of styrofoam, and the armour is partly craft foam and partly foam from groundsheets.
Good luck with your Mercer, make it awesome!