Acoustic Guitar Construction

I am gonna be working on a KMG 00 kit for myself in the very near future.
I was thinking about a center insert through the back. As you know the back halves are already glued together with Ken's kit. Is there an not to risky way to install this insert after the halves have been glued together, and what do I need in jigs, or tools.

Thanks in advance.

I won't say its without risk - but its not terribly difficult to do. I have met a few builders who prefer to add the back center strip after joining the plates, with the theory that it create a stronger joint.

I used a .25" downcut spiral router bit in my laminate trimmer - this matched the .25" zipper inlay strip. Carefully measuring the offset to be sure my dado was cut directly down the center. Be sure that if you are using a single straight edge as your guide that you run your router the correct direction, where it wants to pull into the straight edge, rather than wander away from it.

This is the way I did it:

I built a KMG kit and decided to add a backstrip. There is a downside to routing a channel and inlaying the strip. My experience went like this; Careful set up with guides on both sides of the router base. I did a dry fit and it seemed perfect. I brushed a thin layer of glue in the channel and put the back strip in, but it would not seat tightly, so I tapped it gently with a small block and the back plates separated. I cleaned up the glue from all surfaces, re- glued the back plates, re- routed the channel just a hair wider, and glued the insert in. When I removed the clamps I had a small gap the entire length of the backstrip, which I then had to fill with rosewood dust & glue. When sanding the back plates prior to finishing I sanded through the now very thin backstrip in a little spot at the head block transition. After posting my experience here I found that many (most?) builders simply glue up the plates with the back strip sandwiched in between. It makes so much sense having the full thickness of all parts for gluing surfaces and no chance of sanding through. I'm not sure of the cost, but KMG offers the completed back with the inlay strip in their kits. I'm definitely following this process on my next build. Hope this helps.

Thanks guys.
Not sure what I am going to do at this point. And if the worst that can happen I that I split the back apart, should be just a matter of glueing it back together with the strip sandwiched between the back plates. Or am I simplifying things too much?


Just thought of it. I would already have cut the groove.

I've routed a few backstrips in with no problem. I use an undersized downcut bit and make multiple passes to get to the exact width. I also rout very deep so there's no chance of sanding through. I've had good luck so far.

John,
By "very deep", how deep is that? I only went 50% of the plate thickness, which is probably why I had the sand through problem.

Brad Hall wrote:John,
By "very deep", how deep is that? I only went 50% of the plate thickness, which is probably why I had the sand through problem.

Depends on the thickness of your backstrip, but I'm guessing I was at least 3/4 to 7/8 of the way through. Just need to leave Anouilh to keep the back together while you glue in the strip. I've seen some pre made strips that were thinner than the back, but the ones I've used were thicker.