Split truss rod block

There are a lot of different ways acoustic guitars are designed. With a truss rod accessed through the sound hole, there's usually a hole in the neck block. I'm guessing that's the design of yours.

The function of the neck block is structural... it allows a bolt-on or mortise and tenon style neck joint to be securely attached to the body. It also provides a large surface for gluing that end of the sides.

If that's your design, I'd fill it.

But there's another style neck joint out there... in that one, the neck is one solid piece. Where the neck joins the body, there are slots cut for the gluing of the sides. Although it's not likely that's the design of your guitar (because it's not as inexpensive to make), if you have that design there's a chance that the crack actually extends into the neck.

So if it's obvious that the neck and neck block are two different woods, go ahead and fill. If it's not obvious, it might be worth having a luthier take a peek.

Thanks, Noteboat. I appreciate your help.

They are definitely different woods, so I'll give it a go. Can you recommend a suitable glue/resin? Would you advise removing the strings to do it (it's just about reachable as it is) ?

Uncle Al

I'd definitely take the strings off, because that'll make it a lot easier to do.

I've never done a fill on a neck block, so I don't have any personal recommendations. But since it's probably impractical to clamp it while it dries, I'd hit a woodworking store (like Woodcrafters or something similar) and see what they have - maybe in prepackaged syringes?

Thanks again, Noteboat.

I've done it now. I took the strings of and glued it with epoxy resin (from a syringe kit). I was able to clamp it too. I've just taken the clamp off and it seems fine.

Incidentally, I mentioned it to the guitar shop owner where I bought a new set of strings for it, and he suggested that it might be better to do nothing! Too late!

Uncle Al