Various ways of making armor and weapons.

Links-

http://www.kamuicosplay.com/tutorials

http://entropyhouse.com/penwiper/costumes/helmsdeep.html

http://www.amethyst-angel.com/cb/special_papermache.html

http://kurerukreatis.deviantart.com/art/Cosplay-tutorial-Helmet-of-Wow-328220166

http://www.amethyst-angel.com/cb/ffvii_cloudpauldron_wonderflex.html

http://www.instructables.com/id/Using-Paper-Resin-and-Fiberglass-to-be-the-Maste/?ALLSTEPS

BONUS

Armour from foam flooring tiles - http://bioweapons.wordpress.com/2010/06/21/mass-effect-n7-armor-build/

http://www.tamasoft.co.jp/pepakura-en/

http://cast-a-walker.blogspot.co.uk/2008/08/resin-casting-step-by-step.html