Finishing the guitar

20180710
After 2 years of playing the guitar, I finally get around to start finishing the guitar.
The string broke so I removed the string and started the finishing process properly.

The sound has developed to be very good.
In terms of sonoriy I would rate it the best amongst my guitar. (2nd is followed by Guitar #5)
Other guitars were generally great at the trebles but OK at the bass sonority.
This guitar has both clarity, separation and great bass sonority.
I attribute this to the bracing and the low air resonance.

First I sanded the top even with various grits: 150, 240, 320, 400, 800, 1500.
Then I pore filled the rosette ring with CA glue.
I tape up those areas which I don't want to coat with shellac.
Finally I coated the surface with thin coats of shellac without any oils.
I noticed some patches of unevenness on the rosette area which means I did not sand it even after the pore filling.
Likely I will need to remove the base coat of shellac in particularly the rosette area.
But the grain really pops out after the shellac is applied

After sanding the top with various grits

Pore filled the rosette with CA glue

Applied a the base coat of shellac.

20180713
More FP in progress the shellac building up slowly.

Slowly building up the shellac. Look at the silking on the top (medullary rays)

Another view

Look at the rosette, the grain starting to pop out

More FP in progress, beginning to get some shine

Starting to get the shine

20180724
Some more polishing to go.
The shellac build is good but after spiriting off I lost some of the shine.
Hmm I am supposed to burnish the surface to compact the shellac but with the bridge in place it's kind of hard to do that.
The excess oil were removed with paper towel.
Those hard to reach area (e.g. bridge area, area besides the fingerboard) are easier to reach if I put a coin into the mueca during the polishing.

Shine is there but I will need to level sand the surface

20180731
I level sand the surface using oil and 800 grit.
Then I followed up with more polishing.
The effect looks much better

After level sanding with 800 grit and oil

The surface is smoother after the level sanding.

More polishing

20180920
I began to finish the back.
I stopped a while as I was thinking what to use to finish the back.
In the end I decided to use shellac.
Pore filling with dust wasn't working out too well.
In the end I use pumice.
The trick to use pumice is not to apply too much of it.
If too much is used it will get tacky and discoloured.
When that happens use more alcohol to level it out.

After a few bodying session, the coat builds up fine.
I polished a bit and things looking good.
I level sand a bit in between.
Some pores are still quite visible so I just a bit more pumice to fill them.
That's the good thing about using FP and pumice to pore fill; you can always go back and do it any time.

After a few bodying sessions.

Pumice

20180927
After a few sessions of polishing this is how it looks.
I level sanded a few times.
There are some along grain graduations though so when I do spirit off I did it in a traverse direction.
It did level it a bit so i think i will continue a few sessions to level them.

After a few sessions of polishing

Can see the reflections

Jointing the top and back

20180814
I began the build by shooting the various boards: tops and backs.
After making sure that no light passed thru' the joint seam, I proceed to joint the 2 halves of the boards.
I have only 2 sets of jig to clamp the 2 halves so I joint the tops first.

Shooting the back of #10

Back of #10

Shooting the back of #11

Back of #11

Checking the top seam

Jointing the top using my jig. Tightening the rope using a wedge.

20180821
The top is removed from the jointing jig.
Next the back is glued with the same method as the top.
The glue remnants is also removed by scraping from the jointed area on the top.

After removing from the jig

Jointing the back #10, tying the rope.

Inserting the wedge

Jointing the back #11

Scraping the top joint

20180828
After the glued dried and more than 48 hours, the 2 backs are released from their jointing jigs.
Looks great!

#10 back jointed

#11 back jointed

Starting on 3 new guitars: #10, #11, #12

20180814
I will be beginning a few new builds: 2 new 6-string guitar and 1 new 7-string guitar
The guitars will all be using RW back and sides with Lutz spruce top.
The RW back taps very high pitch with lots of sustain.
Think these will be interesting build, be sure to stay tuned.

Repair a Ukulele

20180813
A ukulele came in for repair as the bridge came off (another case of bridge repair).
The owner has used a shoe glue to glue it back but it was not a suitable glue.
So I had remove the glue remnants.
Upon removing it I noticed the top was scribed with a lot of XXXXX and this is the cause of failure...
Normally top should not be scribed with xxxx.
Glue work best with fitting surfaces and if the top is damaged with xxxx scribes, the surface will not be fitting and the chances of bridge coming off is bigger.
After cleaning the surfaces and sanding both side to have better fit, I applied the glue and glued back the bridge to the top.

Scraping the glue remnants on the bridge

Sanding the bottom of the bridge

Removing the glue remnants on the top.

Sanding the top.

Fitting both surfaces

Closeup of the scribing marks on the top (likely cause of the failure)

Gluing the bridge to the top.

Repair a guitar

20180801
I have a guitar coming in for a bridge repair.
Nothing too out of the ordinary.
But I did noticed that the top has some wavy curve across, but I did not see any damages to the butt area.
So I think the cause of the bridge coming loose is probably due to changes in RH.
Anyway for this bridge repair I use a caul underneath the top and clamp with 3 bridge clamps.
Before applying the glue, I clean the surface with sandpaper.
After that I applied the glue and clamp.

The gap developing at the back of the bridge. The top has a noticeable wavy curve.

Cleaning the surface with sand paper

Apply glue and clamped

Another view

Caul and clamp used

The bridge glued nicely

20180813
The guitar has been strung up for about a week and the bridge still stays strong.
I prepare a new nut for the guitar with a closer string spacing.
The maker has put a pin in the middle of the nut slot which makes the making of the nut a bit more challenging.
So I just make the nut to fit the slot and file the string spacing accordingly.

New nut with closer string spacing.

Guitar all strung up and ready to play.

Installing the binding and purfling

20180622
Next I cut the binding channel on the back of the guitar.
Normally I will cut the top binding channels first for but this time round I cut the back bindings
Also I bent the bindings.
I thought ebony was hard to bend but they came out pretty good.
Think overall my method had improved as I use another iron to heat the other side of the wood.
That really helps in the bending.

I describe a bit about my new method of bending.
Actually there isn't much difference from my previous method.
Previously I will use 2 blocks to support the back of the curve portion during the bend.
However the heat is only coming from the hot pipe side.
So this might result in some breakage for some woods that don't want to be bent.
With this method, the concept is very similar.
The bend at the curve part is now supported by the iron; but I can only support one side instead of two.
I need the other hand to hold the bindings.
The good part is the iron will also apply the heat to the back of the wood which greatly reduce the breakage.
Also by pulling the wood thru the compressing heat mold formed by the pipe and the iron, the wood acquires a gradual bend shape.
This will also reduce the amount of sanding required for the woods after bending.

After cutting the channel, I fit the binding and they fit perfectly.
I did some adjustment to the trimmer to cater for the arch back surface.
Thus the channel came out referenced the sides instead of the top.

Bending the bindings using a hot pipe and an iron. Works great!

After cutting the binding channel. Chips everywhere.

Test fitting the binding.

Repair a guitar with bridge problem

20180417
a guitar came into my workshop for a bridge repair.
This is not the usually bridge lifting off problem, but the tie-block has came off.
Naturally I was surprised as this is the first time I have seen such a problem.
Anyway I thought the fix will be simple: to glue back the tie block
There owner wanted to change the whole bridge but I digressed.

• There were no missing pieces
• There was no problem with intonation / i.e. saddle placement

Hence I stick to my plan to glue back the tie-block
After gluing I strung up the guitar

Tie-block broken

Glue back the tie-block

Strung up

20140424
Unfortunately, after a few days, the tie-block came out again to my surprise.
True enough the glued joint is stronger than the wood itself, but the break as another layer in the tie-block
What this means was that the bridge wood has some sort of weakness in it.
So the solution now is to change bridge entire and build a new bridge.

Tie-block broke off again - different layer

Still with the strings attached

20180507
I began to remove the existing bridge.
Before that I scribed the edges to prevent the lacquer from chipping off as I remove the bridge.
I also took measurements of the scale length / compensation and bridge height.
To my surprise, the bridge began to crumble and broken in pieces as I remove it.
I followed my usual way of removing the bridge heating the platter knife and insert in between the bridge and top.
No heat was apply to the top
This was to ensure no excessive heat was applied to prevent other glued parts from coming loose from the heat
So the problem was with the bridge wood after all.
But I wonder what caused the wood to crumbled like that.

Finally after 45 minutes or so I manage to remove the bridge cleaning.
Surrounding woods are undamaged.

Scribing the edges to prevent lacquer chipped out

Heating and inserting the knife under the bridge. No heat was applied to the top. No water was used.

Done

20180531
I began to work on the bridge blank.
First by scraping and sanding the bottom arc to fit the top.
Also I sanded the top to remove the unevenness of left by the bridge removal.
Finally I sanded the bridge blank to fit the top.

Then I saw away the bridge wings and the bridge began to form in shape.

Scraping the bottom of the bridge blank

Sanding the top

Sanding the bridge to fit the top

Saw away the wing of the blank

Bridge taking shape.

20180619
Half way I decide to use pre-made bridge as I can complete the process faster.
And the fit was quite good.
So I use epoxy to glue the bridge.
Not my usual habit to glue the top but in this case as there were some gaps in the surface, a epoxy glue will be a better guarantee.
So I fitted the bridge and applied the glue to both surface, followed by clamping.

Bridge glued.

20190620

Next I removed the clamp and make a new saddle, change the tuning machine and string up the guitar.
The bridge glue job looks good.
And the guitar sounded nicely.
I touched up some of the finishes but they certainly don't look perfect though.

Bridge glued nicely, new saddle made.

Tuning machines changed