I thought I would share a technique with you which I picked up from a great builder who is not a member CBN. I think you can argue that a 3 or 4 string CBG doesn't really need any additional neck strength, but I've found myself making thinner necks recently, and I'd like to make sure they stand the test of time. I am also gearing up to have a go at making a 6 string from scratch so this is a technique I will need to learn sooner or later.
So, to do this you will need some mild steel bar. I got 3x13mm. A 4 metre length cost me about £4. The postage cost twice that but it was almost worth it to see the look on the delivery driver's face when he handed over a 4m long cardboard tube. You also need a router, and a bit of the correct width and depth for the bar.
I used the parallel guide on the router to slide along the side of the neck to cut the channel. I used a high speed and 4 shallow passes to get the finished depth (which needs to be a tiny bit deeper that the width of the bar)
It fits. Now time to glue it in. I used epoxy with a long curing time. Getting the glue in the channel is quite tricky.
I held the bar in place with clamps and left it overnight. Make sure you put something between the clamps and the neck so you don't glue them together!
Once the epoxy had set I lightly sanded the surface to remove any residue.
Then just glue on your fretboard as usual and you have (hopefully) a super strong bow-resistant neck that you can shape a bit more aggressively than one without a strengthening rod.
Have fun!
RK
