Official Luthiers Forum!

Hi all, I'm new to this forum. I have an old twelve string which I am going to convert to a resonator, mainly because the old top bellied. Being poor I am going to spin up some homemade cones (non spider type), I have a wood lathe and various tools etc. What I need to know is what thickness of aluminium to use? I intend to make a 9" (is 9" a standard size I've seen 11" advertised as well) cone how deep should the dishing be? Any help would be greatly appreciated as I've only ever seen resonators from a distance.

I'd recommend buying a National cone as a guide
not only for shape but end results. There's some
tricks to cone design, especially at the edge.