The one I saw showed him gluing the bundles together too. What I haven't seen and would like to see is more of them preparing the rods to glue together. They just touched on it in this one and not at all in the previous one I saw. I haven't been able to find any books on the process either. It may be something they don't want to talk about that much.
Someone I consider a master woodworker once told me that a master woodworker is not someone who never makes mistakes. He is someone who is able to cover them up so that no one can tell.