27" scale length and truss rod

[guitman32]

I am going to be building a 27" scale baritone, and I am wondering if I need a longer than usual truss rod. As of right now I am planning on using a stewmac Hot Rod, but I am unsure what length I should use. With a 27" scale, the total FB length, from the nut to the end of the neck, will be 20.629 inches (that is including an imaginary 25th fret for the extention past the 24th).

Should I go with the 18" scale length rod, or should I make my own and go a bit longer? I was also thinking of using some carbon fiber rods to reinforce the neck...what do you think?

[Scott Rosenberger]

the regular rod should be fine, I mean if I'm not mistaken the difference between a 25.5" and 27" scale neck is only about 3/4"