This beautiful older model Kamaka uke came in my shop in rough shape..
The back had a big separation right down the middle. This is very common in our dry climate. This instrument was built in Hawaii where they have much more humidity then we see. Over the years the dryness caused the wood to shrink and finally separate.
First step was to try and get some humidity into the instrument and see how much movement we would get in the woods. Here you'll notice the uke wrapped in a bag. I do this to contain the moisture and help the process along. Inside the instrument there are several humidifiers, and every couple days I would re-wet them and continue the process till I was comfortable with it. This process took weeks to achieve, but its very important to get the humidity back up before we proceeded any further.
After I re-humidified it, this is how much the crack closed up.. It was considerable, and with this much movement I was not confident that it would not re-open. So my next step was to remove the back and add a small center strip.
Off with the back!
I worked this palette knife all along the back and side seams, slowly breaking the glue joint. This was a very long tedious process. I had to take it in small steps in order to leave it intact as possible.
There we go! It came off very clean which I was thankful for.
Here's a shot once I got it off the instrument. As you can see, the center is no where near being joined properly.
My plan was to separate the pieces and add a small center strip to compensate for the shrinkage.
Here I have added a slice of wood right down the middle. I left it proud, so I could then carve it right back into the top.
A little carving, and sanding and before too long I had it looking pretty good.
Turned out really nice. Now it just needed a little coat of finish and glued back on.
I didn't take any photos of the finishing process, but it was a simple hand rubbed shellac finish.... Here I'm gluing the back on. I used a low tack tape to hold it on while the glued dried.
And here's the final outcome. Once I got it all strung and tuned, this uke was amazing! It had a wonderfully rich tone and played like a dream...
On to the next project!