Thanks, everyone.  

I contemplated doing more of the carving by hand and with an angle grinder but I would still be carving and grinding.  I probably would not have attempted this without a CNC to do the bulk of the shaping.  Should I ever decide to make another, I have modified my design to make the joints easier to do and eliminate the external sleeves.  Ideally, I would find some aluminum tubing of the right sizes to make the joints stronger.  That is how some of the commercially made ones are done.  

My friend took the alphorn to a friend of his yesterday who is a professional musician and plays the alphorn at various festivals around the world.  She tried it and thinks I have some air leaks at the joints I need to deal with to get a better sound.  I told my friend to try to hook up a compressor and block the end of the bell to get some light back pressure to see if he can figure out where they are.  

--Nathan, TX. Hire the lazy man. He may not do as much work but that's because he will find a better way.