Can someone help me on my cosplay costume?

I'm making a costume for Otakon, which is an anime convention for those of you who don't know, and the character I am dressing as is Zack Fair, from final fantasy crisis core. I am trying to make his sword with foam so I can whack people with it. :D lol! The sword is gonna basically be a PVC pipe stuck through a piece of foam cut to be the shape of his sword. How in the world would you get the pipe through the foam without the pipe going through the sides. (This happened already! XD) Any ideas?