Double Bass Repair broken neck on upright bass

[Aaron Van Wyk]

Thanks! Just glued up with T-88. I used a nice thick maple board to help keep everything lined up. Plastic tape over the board to keep the epoxy from sticking. I did a dry run to make sure I could get the pieces in place and properly aligned. There were a number of splinters and bits of wood that kind of exploded when the neck broke. These small voids will now be filled in with epoxy. Clamped with light pressure just to close the joint. I'll have a fair amount of cleanup to do before the next step.

 

[KUNGfuSHERIFF]

While you've got the board off, now would be a great time to add a tapered shim to reinforce the neck and achieve a taller bridge.

 

[Greg Clinkingbeard]

While you've got the board off, now would be a great time to add a tapered shim to reinforce the neck and achieve a taller bridge.

I've done several Kays this way and a shim of about 3/8" at the heel tapering to nothing at the nut will usually yield a bridge height of about 6". If you go this route, because you have epoxy at the repair you could epoxy the shim and use hide glue for the fingerboard.

 

[Aaron Van Wyk]

I've done several Kays this way and a shim of about 3/8" at the heel tapering to nothing at the nut will usually yield a bridge height of about 6". If you go this route, because you have epoxy at the repair you could epoxy the shim and use hide glue for the fingerboard.

I thought about adding a shim on top of the neck under the fingerboard but running it all the way up to the peg box to reinforce the break. Bridge height is currently 5 3/4" so I don't think I need to gain much height. Routed in two 1/8"x3/8"x12" channels for carbon fiber reinforcement through the break all the way to the peg box. Glued in with T-88 again. We'll see what it looks like when I get it all cleaned up.

 

[Greg Clinkingbeard]

You could do that because these necks tend to be thin. A 1/4" shim won't add 1/4" at the bridge but I would personally like a beefier neck. The CF rods are a good move.

 

[Aaron Van Wyk]

Thanks for the advice, Greg. I did end up using epoxy to attach a ~1/8" maple shim on top of the neck so the way up to the peg box and then hide glue to reattach the fingerboard. Extending the shim past the fingerboard let's me use the existing nut without modification. Sad to cover up the beautiful figure in the fingerboard with black but that's how these bases are. Now I just have some cleanup and finish to do. I think that this should hold up over time no problem.