I'm with the bubble wrap folks. I've shipped a bunch of sticks this way and never had a problem. I trace out the shape of the blade on two small pieces of cardboard (cut it out a little bigger then your tracing) and then tape them on the front and back on the blade to protect it. Wrap everything in a couple layers of bubble wrap, tape the crap out of it with shipping tape. I usually put the shipping label on the blade. Done
I really dont think there's any advantage to frankensteining a box together vs just wrapping it. Also, it's surprisingly affordable to ship this way.