Ukulele Part 4: Top to Bottom

First things first:  This post covers the "top" of the ukulele but I did install the back first (as you'll see in some of the below pictures).  It just felt redundant to show both sides as the process is mostly identical except the top requires more...
...well, more of everything...

What it is

This kit came with pre-shaped braces that just needed to be glued into place on the top and back.  They would have been fine as-is but I felt the need to monkey around with them.  According to many guitar builders - shaving down the braces can really shape the sound of the instrument. The basic idea is that the braces should be just strong enough to keep the instrument together but not so strong that they inhibit the top from vibrating - which is where all the sound comes from in a ukulele (and guitars as well).  I've even heard it described as removing just enough material so that the instrument doesn't self-destruct.

The above picture is how the braces came to me.
The below picture is after I was done with them

What it shall be

You can see that I tapered the ends but what you can't see is that I also gave them a haircut.  The braces were much shorter and thinner when I was done with them. For those of you playing the Luthier Home Game - I didn't 'scallop' the braces - I just made them thinner all around.

In my last post, I spoke about cutting a notch for these braces in the sides.  The reason I stated that some of the notches were unnecessary was due to the amount I removed in the above process.

What it was

There are three main tools to do this kind of work:  a sharp chisel, finger planes, and sandpaper.
I don't own any finger planes but if I ever get into making acoustics more often - I will invest in some.  The chisel worked but as you can see from my above efforts - it was a bit sloppy.
The sandpaper really helped clean things up after I was done with the chisel.

Also for the people playing at home - I did "tap-tune" the top.  This is a fancy way of saying that I stopped chiseling every couple of minutes and tried tapping the top to see how it sounded.  When the top stopped making a "thud" sound when tapped and started making more of a distinct note or tone - I knew I was close to being done carving the braces.

That don't look right

Just before I started working on the braces I became aware that the top had a pretty significant bow to it.  This would be fine if the bow was bowed in the other direction.  A slightly curved top is actually a good thing in an acoustic/ukulele.  A slightly concaved top...?  Not so much.

What I think happened here is that the weight of my clamps may have bowed the top when I glued on the braces.  The braces themselves were fairly flat.  And no - there was no difference in the size of the bow between when I started carving the braces and when I finished carving them.  This just is part of the top now, I guess.  We'll see...

Ready...?

I don't normally sign my work but the one previous acoustic instrument I built - I did.  So, it felt right to do so this time.  And since this was a gift from my wife...
...well, you get the idea...

1...2...3...

Awwwwwwww!

As you can see from the below photo - the back is already glued to the sides.  You may also be able to see the notches I was talking about.  Finally - you can see those screw-eyes surrounding the uke body.  Those are going to become important in a bit.

That's a mildly ukulele shaped thing, right there!

What may be hard to see in the below photo is that the glue has been applied and we're ready to put the top on.  I have the habit of overdoing it with the glue.  I haven't poked around inside of this uke yet with a mirror but I know there are some glue drips in there.  Judging from the amount of glue drips that I wiped up on the outside - it's not even a question of if but how many.

I'm hoping that extra glue is going to come in handy as we'll see in a sec.

sticky sticky

The green stuff is one big rubber band.  True story.  It comes with the kit for this very purpose.  And it does a pretty good job of putting even pressure on the top while gluing.  The trick is that your top can't have a bow in it and your sides need to be even for this to work as designed.  Neither of these things was true with my uke.  Sadly, also a true story...

This is where the screw-eyes come into play.  I threaded the elastic through each of the eyelets but if you used bigger screw-eyes you could wrap the elastic around them.  My way was a bit fidgety but it seemed to work okay.

Insert Dad-joke about being 'all tied up.'

 As you can see - it puts a decent amount of clamping force on the top.  Enough to squeeze out a lot of glue.  But it wasn't enough clamping pressure.  There were still spots where the top wasn't touching the sides.  This could have been because the neck or heal cap was taller than the sides (although I checked that) or it could have been the sides weren't even (checked that too), or it could have been that pesky bow that I mentioned (not much I could do about that one).  But I'm guessing it was all of the above.

That'll buff right out.

 So, we improvise!

Necessity is a motherf----r

That's about two feet of books sitting on top of the uke.  It helped quite a bit but there were still a few spots where the generalized pressure of two feet of books just wasn't enough - so I focused the weight with a couple of blocks and a stack of coins.  This really put the squeeze on.  There still ended up being one or two spots where the top and sides don't appear to be touching but I'll have to do a flashlight test after everything dries.

Is it me or does it look like the wood is bending?

What you don't see in the pictures is the gallon jug of windshield wiper fluid I put on top of the books.  If I had to guess there was probably 30-40 pounds of weight on that top - plus whatever pressure the elastic band was creating.  That's a pretty strong body.

Well, if all else fails it'll make a nice uke-shaped birdhouse.

Next up:  let's trim those overhangs and sand the body.

Soon