To make Inuyasha’s Tessaiga sword, we sandwiched a dowel rod between two layers of pink insulation foam, using liquid nails to adhere them, and let it dry overnight.
Define the sword's edge by using an electric sander, or in my case, a drill with a sanding attachment. Important: Always wear a dust mask whenever sanding foam!
Once the foam has been shaped to your liking, give it three coats of gesso to fill in any minor nicks and prepare it for spray-paint.
Once the gesso has dried, spray paint the sword silver, hot glue faux fur around the base and wrap the hilt with black nylon ribbon (both materials found at Joann Fabric).
This project takes approximately two days – the longest part being how long it takes for the glue to cure.
Keep in mind that foam-made swords are still subject to nicks, scraps and tears. For this reason, you should always warn the person who wants to pose with you while “clashing swords” not to really clash your sword with his (speaking from experience)!
But if your sword does get nicked, you can simply patch it up with some paper clay, sand and repaint.