Originally Posted by touchmon
Just want to make sure I understand this part correctly. After putting the dowel in the center, for the filler, that means all of the area around the foam that isn't covered by the dowel? So it will be on the same width as the dowel on the one side? I also really don't know much about fillers.
Yup, you'd fill in the area of the channel not occupied by the dowel so that the surface of your blade would be smooth again. Your channel should be deep enough that when the support rod is inserted that it is in the middle of the blade like a sword hilt normally would be.
Didn't have access to any of my progress shots at the time, so hopefully that little sketch will help illustrate what I'm talking about.
Bondo is a common filler, you'd need to seal the foam first however. Expanding foam is often used for things like this. Wood filler can also work as can various construction fillers. It really just depends on what you want to work with.