Acoustic Guitar Construction

My first first falcate classical guitar had a lower resonance than I have had in my four falcate braced classical guitars. It is a nice looking guitar with a panama rosewood back and sides. The guitar was not bad sounding but did not really have any punch on the 1st string up the neck. I also have been wanting to try a retop where the binds are kept intact. I saw this method posted in a few places on the internet.

I have not yet completed the re-top but I have got to the point where I think I can pull it off. The trick to the retop is to route new top to be the exact size to fit into the bindings of the guitar. Picture will show it best, but the basic idea is to mount the new top onto the old top spaced a bit from the top. A binding machine is then set to cut the top to the inside of the binding or binding and purfling line using the guitar itself as the index for the binding machine.

FIrst off I removed the bridge of the guitar and prepared jointed and loosely profiled the new top.





I used double stick tape to put down a bunch of spacers on the old top. I just cut up a bunch of the waste from the top.





I set the binding jig to just cut past the purflings, I used my test cut to check on the guitar. Then I routed the new top leaving the bindings alone







I cut the top out and used a bit of heat to loosen the glued down pieces.





The binding survived although I did pull a bit of the purfling when removing the top pieces for the linings I used heat to remove the rest of the purflings and will reinstall.

I made one of my classical wood ring rosettes, cheating a bit by installing premade rosette and routing out the center end grain tiles.









The new top fits right in, so I am ready to brace it using the experience I had gained on my last four classical falcate braced guitars.

What a cool process on doing the top, and I like the idea on using the rosette as a basis for your wood rosette. I may try that.

What an education! Thanks very much.

And a question about the back braces. Not the conventional array, at least from a steelstring perspective. Is the set of finger braces used instead of a fourth lateral brace? I'm ignorant as to how classical bracing differs from steelstring bracing.

Much obliged, and thanks again for sharing the project with us.

Thanks guys,

The back bracing is from Trevor Gore's plans. He uses it for both steel string and classical when he wants to make an active back. The lower brace is carved to fine tune the backs resonant frequency. With full sized braces I find the back is pitched with a 250 or so Hz resonance frequency. I have tuned the lower brace and dropped the backs resonant frequency as low as 224 Hz.

Trevor plans include a 4 brace design for more of a non active reflective back. He views both styles of back brace designs as good. The active back will sacrifice some volume for tone. So a design for a loud concert guitar played without amplification in large hall might call for a non active back. I like the tone of the active back and my guitars are still loud. So that is what I generally make.

I've used back bracing similar to John P., also inspired by Gore/Gilet and by Stephen Sheriff (Edwinson Guitars), whose top bracing pattern I use. One aspect about the back bracing that I like is that the lower cross (transverse) back brace is easy to reach through the soundhole so it can be shaved to tune the back resonance after the guitar is built.

John, these are a lot of fun. I do mine similar to what you did. You may find this interesting; I use a router to cut the top off. Here is the setup and results.