Hello and welcome to another one
of my videos. In this one we are going to be looking at
musical instruments again. Now, the same day that I uploaded
the video of making a ukulele a neighbor came visiting and he brought
me a guitar for repairing it has a crack in it. It is this. It’s a
kind of ukulele, it’s not quite a ukulele. It is a Cuatro Venezolano. A four string.
A Venezolan four string. But we are here in Colombia and they
also make here as well. They are a kind of ukulele but there are
some design differences in them and it’s quite genius, the simplicity
and budgetness of it. So, before we get onto repairing the crack
which I will show you, how I do it, quite successfully, we can look at some of
the design differences between this, a Cuartro Venezolano, and a Ukulele. Now, the shape of the body is more or less
the same as the tenor ukulele But the body itself is deeper. It is 10cm
in stead of 6cm.. The joint of the neck to the body
is a Spanish style joint that goes into the body with a groove, different to
the dovetail joint. The neck itself is longer, thinner
and straighter. There is only about a 2 to 3mm taper on it and most strikingly
is, there is no fret board. The top and this is genius, the frets are straight
into the neck itself and the body top extends to the first fret which does not
come down onto the body, so that’s only 13 frets. The thirteenth fret. The body
comes up to it and covers that joint there There is no raised fret board.
That’s quite striking. Now down here the simplicity of the bridge is amazing.
It’s just a stick with some holes through at the right height. 5mm up. I like that.
Now up the top here the head itself is nice and thin as usual, but it is not
joined as a scarf joint. It’s just butted in. Many of the
Cuatros Venezolanos have the scarf joint to make the neck and also even the pegs
are so budget they are nailed on, they are not even screwed on.
But that is a difference there. and the profile is a long stick
just curved around, and then an end grain piece here. Quite thin
that becomes part of that Spanish joint. Now, inside…They actually have a decent
volume but very twangy because there is virtually no ribbing
or support. The back has no ribs at all and there is just two ribs here. There is
no support for the bridge, and it is very thin.The fretting are only
little triangles every so often around the body holding it together
so it’s very light, makes a decent sound but that makes it extremely weak,
and therefore you get cracks on either side here, and the sides also
and as we can see here, a big crack in the back because there is no support
whatsoever for that 2mm timber. So, there are some design differences
in the cuatro Venezolano and the ukulele. Quite genius, I think it is cool. I might
even try making one. now , let’s repair that crack. Now, the task in repairing a crack
is to make it disappear. get the two sides to go back together
not only this way, but also up and down. Someone else had a try at repairing this
and they did not get it aligned and now you have got this terrible lip.
Now that it is glued it is very difficult to get that undone and to repair it.
So basically they are stuck with that, Over here they did a better job
of getting these ones together They just closed that down
and they used some sticky tape to pull that together, and that worked
fairly well. They did a good job there. This one here they didn’t get it quite
together. Structurally it is sound. But you can still see that crack as well.
We can do a better job by using another technique.
And we can make it almost disappear. I am going to take some nylon thread.
This is from a kite , but you can get some other thread, and take around about a half
a meters worth, or a foot and a half of thin nylon thread.
So I am going to find the crack and open it up just slightly to be able to
feed that thread through. I am going to put probably three here
every 5 or 10cm, you will get to know to feed that through.
It helps to take the pressure off the stings. Undo the strings, so that it
takes the pressure off, so that the crack will go back easier. Pull the thread
through your sound hole and then thread it on a needle. Now, it is always a good idea
although you can do it without it is to get a little square of timber as a cleat
they call it, as a reinforcement thing. and poke it through very carefully
without breaking it. So, you are going to thread it through.
Like that which we will glue and then take your thread off, your needle off.
and then take a little block like this. It is a piece of fretting. Wrap it around
a little bit, a few times and tie it off. And then when we pull the thread from
the other side, when we pull that,it will pull that thread
in and give it some tension there and bring it flat. The little block on
the other side will help hold that cleat against the crack so that
it is going to be like a patch on the other side. When it comes to gluing
it up, you put the glue in, the cleat and the crack, and then you are going to
apply tension to it. A rough and ready way of keeping that
tension on, is getting a stick winding the thread around that a few times
roll it right down as far as you can then clamp that secure with a clamp
or something, like this and then put something under the end
of that, let’s see, something like this To lift it up and keep the tension on.
That is a rough and ready way of doing it But I have developed these little
ratchets systems to put the tension on and also the flat is to hold the crack
flush as well with the same thing So let’s make one of those. First we will make the ratchet,
by scribing around a broom stick handle. A line around, then make a series
of cuts outwards. Then come in on an angle and
cut out that tooth there. Find the center.
and drill a hole. Cut it off. Find the center and drill a little hole
on the other side. You will need a board that’s going to take
about twice the width of that and we will need two of those.
twice the width of the ratchet. So, we are going to drill a hole
through both of them to take the axle for those. So I am going to put it there and then
with a little stick, possibly with a point on an angle, then I am going to nail that
through there, with a little nail So that it will pivot.
Maybe I will do a pilot hole for it. So there is my ratchet. Now, to stop it sort of twisting like that
let’s put a piece of board across here and rebate it into there so that it will
give it lateral stability. and we should be able to do that
with a knife. and I am going to put a little nail
in there that I can hook the thread over when that turns.
So the idea is make a loop in the end of your nylon, feed it up the center of
the machine and loop it over the nail and then wind in the slack. So apply your glue, take up the slack,
engage the ratchet, and there you have got the tension you need.
So apply some glue to the cleats Turn it over, pull them tight. and then, work some glue into the crack
the full length of it. and then, wind up the clamps. activating the ratchets.
If necessary you can apply some sideways pressure with a clamp
to just close that crack. but basically there they are. Nice and flush. You can’t even
hardly see the crack. Now, if you can, make sure those cleats go
across the grain, in stead of with the grain, so that it is going to
hold it properly. You can clean up those faces of
excess glue with a damp cloth while they are drying, to make your cleanup job
easier later on. So now I can undo those clamps
when it is dry and pull those out. With the reinforcing cleats permanently
glued on the inside. So there we have the crack repaired
nice and strong. And the crack is almost invisible.
Here it is, just about the same as the grain.
Give it a good polish up and even another coat of lacquer and you can hardly see it. Out of tune but, there it is, fixed.