Luthier Tips du Jour - Murphy's Law


Uploaded by OBrienGuitars on 11.08.2009

Transcript:
The expression, “Whatever can go wrong, will go wrong” is especially true in lutherie.
How many times have you been totally focused on an important step and…

Go ahead, admit it! It has happened to all of us.
The good news is that it is pretty tough to get to a point where you can’t recover.
There is usually a solution and in this video I want to address a few scenarios
where things can go wrong and then what to do about them.
The example of a side crack is a pretty easy fix, especially if it is a clean break.
In this case I would just use a thin viscosity CA glue to glue it back together.
Make sure that you clamp the piece together correctly so that there are no gaps or unevenness.
Since the CA glue is like water it flows into the crack.
You could also use another type of glue to make this repair
but you would need to apply the glue to the crack before clamping.
With a little light scraping and sanding the side is as good as new again.
Another common misfortune is to break a binding,
either while bending or while installing.
With Murphy’s law it was probably the last one you had too.
Well, once again if it was a clean break you might have success gluing it back together.
This trick works really well for darker colored or highly figured bindings
as the glue joint will disappear.
In this case I would use a medium or even thick viscosity CA glue.
Once the binding is scraped and sanded it is as good as new and ready to be installed.
This next one is a little more difficult.
I had a 1968 Brazilian rosewood Ramirez come into the shop with two hairline cracks in the back.
As you have already learned, a hairline crack is easy to repair as you are building.
However, this guitar already has a finish on it and this adds a degree of difficulty to the mix.
The first thing I did was make some cleats that will be used to cover the crack from the inside.
This will help stabilize the crack.
I made the cleats out of Indian rosewood as I feel it to be more stable than Brazilian.
The next problem is how to strategically place them in the guitar.
There are a couple of ways to go about this.
One way is to use magnets.
I start by placing a magnet over the crack from the outside.
I cover the finish with tape to not scratch it
and also cover the magnet so that it will stay in place.
I then place a small piece of double sided tape on another magnet and then stick the cleat to it.
I apply glue to the cleat and reach into the guitar.
The force of the magnet will guide me to the exact location where I need the cleat.
If you can’t reach in the guitar far enough,
you could make a tool like this one to help get the cleat into those hard to reach places.
As you near the correct location the magnet and cleat will magically jump from the tool
to the designated spot and be held in place by the outer magnet.
If you don’t have magnets you could drill two small holes
in the cleat and place it on a piece of thread.
You could then drill two small holes along the crack where you want to place the cleat.
Then you can thread the string through the soundhole and into the holes in the back
and pull on them until the cleat is seated in the correct position.
Hold this for a few minutes while the glue sets and then trim the thread or pull it out.
This trick works really well on really dark colored woods
because the two holes you drilled can be filled and will disappear.
Now the finish needs to be repaired.
I place a couple pieces of tape
along the crack to outline it and keep the glue from running everywhere.
I then place thin viscosity CA glue to fill the void where the finish has separated.
A tooth pick works well for this.
A small razor blade with tape along the edges can be used to lightly scrape the glue
to level it with the finish.
I then lightly sand the area up to about 1000 grit.
Afterwards the buffing wheel brings the finish back up to a high gloss.
You could also buff it by hand.
No more cracks and the finish is good as new.
I will demonstrate how to fix a large open top crack on this piece of scrap.
First of all makes cleats and install them to stabilize the area.
Since it is a large crack, you will need to splice in a
piece of wood that matches your soundboard material.
Use a straightedge and a razor blade to cut a line
at a 45 degree angle on each side of the crack.
You are cutting a V in your soundboard.
Carefully remove the excess wood.
Using the same species of wood as your soundboard,
use the straightedge and razor blade to cut
another strip in the shape of a wedge or V.
This piece will be used to fill the slot you just cut in your soundboard
so it needs to be a good fit.
To glue in the splice I like to use LMI white glue or hide glue.
It only takes a small amount.
Place the splice in place.
Notice how it sits a bit proud of the rest of the piece.
I like to place a piece of clear plastic over it, so I can see it.
Magnets can be used to apply clamping pressure as the glue dries.
After the glue is dry, remove the magnets and plastic
and use a small block plane to level the splice.
I then use a sanding block with some sandpaper
to completely level the splice flush with the soundboard.
As you can see the results can be perfect if done right.
You will really have to inspect the piece closely to even find the repair.
Another problem area that has a quick fix is mineral deposits in the wood.
You have done your final sanding and you notice
a bunch of white lines or streaks in your wood.
This can ruin an otherwise perfect guitar and looks terrible under a finish.
A fine tip black marker hides these unsightly white marks in no time.
Let’s suppose somehow you drop a chisel on your soundboard and dent it.
Don’t laugh. This kind of stuff actually happens.
Here is a fix for that.
You can use a soldering iron and wet rag to steam the dented area.
This will raise the grain and the dent will disappear
if the wood fibers have not been broken.
A light sanding and the dent is gone.
My last tip is a money saving tip.
You can purchase second grade fretboards and make them look like first grade.
These fretboards usually only have some slight discoloration
and therefore are graded as seconds.
If you use a little black dye on the wood
it takes on a uniformly black color and looks just like the first grade wood.
Let it penetrate for a few minutes and then wipe off the excess.
With the tips I have shown in this video,
instead of hearing this when you have a mishap,

you will hear this instead