Yes ,No truss Rod. Well I hope.

Attached is a previous attempt at this without a truss rod.

Here I simply hollowed out a guitar neck and added carbon and a willow core.

After six months of use this neck is bowing a little more than anyone would like.

Per the previous post.  This might be because I did not complete the carbon Box on the top of the neck?

Also I now believe that the vertical carbon in the center is use less.

I am open to all suggestions.