Welcome to my guitar building blog.
This blog describes my journey into the world of guitar building.
I like to share my experience of building and hopefully it can be of some help to all the guitar making enthusiast.
Hope you enjoy my blog post!
Showing posts with label Repair. Show all posts
Showing posts with label Repair. Show all posts
2018-08-13
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.
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.
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.
2018-06-20
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
After gluing I strung up the guitar
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.
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.

Heating and inserting the knife under the bridge. No heat was applied to the top. No water was used.
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.
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.
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.
2018-04-24
Repair a vihuela
20180425
A vihuela came into my shop for repair, as it's bridge had flew off the top.
Should be quite an easy job the only thing is that the bridge took out some of the top.
Also upon inspection the luthier did a terrible thing, that is to scribe several cross marks onto the bridge and top!!!
Those who use hide glue will know this is a not a recommended action.
Hide glue needs maximum surface fit to have a great adhesion and the vihuela (like any other early instruments) has a small gluing surface.
So the fit becomes even more important.
Finally I decide to sand the top flat taking out those deep scribe marks.
Also when I sand the bridge's bottom surface then I realise the fit was really terrible.
There was deep hollow in the center of the bridge's bottom.
No wonder the bridge will fly out...
So I sand all surface flat and put the sandpaper on the top to fit the bridge bottom to the top.
Finally it was ready for gluing.
I use hide glue for the gluing and apply clamps after the hide started to grab the 2 pieces together.
Some pics of the instrument
2017-09-08
Repairing my block plane
20170804
I had dropped my low angle block plane on the ground and the cap screw which holds the cap level broke.
Argh...
Now I need to try find the spare part or it will become a white elephant.
20170908
I didnt manage to find any spare part for it.
So I turned to use normal threaded bolts instead.
As it's an imperial threaded screw I had to guess the nearest size.
I measure the width of the thread and it's about less than 5mm.
The nearest imperial thread unit I can find is 3/16"and so I ordered some from eBay.
When the item arrived I cut to length and tried.
Voila it works great!
Now I am back in business.
2016-10-28
Repairing a baroque guitar
20160531
I have received a Baroque guitar for repairs.
The guitar was damaged in an accident and the back was crushed with some damage to the sides.
The head was snapped from the neck.
So I was asked to examine the guitar and possibly restore the guitar as close to the original as possible.
Upon examination I would say the guitar is quite repairable.
Though the back was crushed on one side, I would say it's definitely repairable.
The neck was using V-joint and glued with hide glue so the break was virtually clean at the joint.
So no damage to the head/neck joint.
The back's damage looks pretty bad but all the pieces should be inside the body itself so think should able to glue back nicely.
The side's damage is minimal.
The only problem is how to remove the back with out removing the binding...
After much consideration and some advice from the owner's luthier friend, we both agreed that removing the back is the way to go.
So I proceed to remove the back, but with the binding blocking the access to the back/ side seam, it's virtually impossible to remove the back.
So I had to remove the binding first but weren't able to make retain the binding.
Well, no worries though, I have some spare cut-off which can be use for binding.
First I had to remove the binding to expose the back / sides seam.
After exposing the seam I can heat up the joint and insert the palette knife to separate the back and sides linings.
I did it slowly over a few sessions actually.
The hard part was a the brace joining the sides.
The braces sit in a lining pocket but didn't budge.
In the end I manage to lift up the back slightly and insert a 2mm chisel to chisel away part of the brace ends.
Anyway, I had to replace the back braces since it broke as the back was crushed.
Another hard part is at the heel area.
But after much heating and inserting I manage to dislodge the back from the heel.
Luckily the heel area is pretty small.
That makes me ponder the next time I (or some other repairer) need to remove my guitar's back, how to do it?...
Anyway that's another thought next time.

Heating the glue joint before inserting the palette knife.
There is a wetted paper towel underneath the iron.
20160606
Next I proceed to glue up the back.
I am using hide glue as per tradition but also because of it's property
It's easy to heat and reglue without the need to remove the previous glue remnants.
After gluing I used clamps to hold the back together.
I will be gluing reinforcements at the inside once the glue dries.
20160610
I clean up the neck / head V-joint.
Though I believe the original glue used was hide glue, still I better clean the joint to get a clean surface.
Also, I tried to correct the head angle as it was slanted a bit.
In the end I didn't correct much as it will result in a major operation instead.
The fit was better now with less gap between the head and neck.
I could have glued the joint but decide against it.
The owner wanted to reshape the head for a more symmetrical look so it will be easier to work on the head separately.
Then I proceed to glue in the reinforcement for the crack seam.
I use a maple veneer which fits the back maple material.
The shape was a little bent due to the force of clamping tight the gaps, so I clamp 2 plastic to straighten the back.
I also applied glue to the cracked sides.
I noticed that the shape as gone out of shape a bit so when I glue in the back I need clamp the sides a bit to correct the shape.
I also sand away the paper backing for the rose area at the request of the owner.
20160726
It's been a while since I last work on this.
I was busy with my #9 and one other guitar repair.
Anyway I remove those spoilt lining and re-glue those lining blocks.
Also I check the back braces in fact more of the back braced are OK
I just need to extend the lining block to accommodate the braces.
Also I clean away the glue remnants for the lining block
The previous glue used was white glue and not hide
I guess back operation needs longer open time and hence the luthier used white glue instead.
For me it's all hide glue unless those cosmetic gluing.
20160912
I finally closed the back for the baroque guitar.
I also shaped the head to make it more symmetrical.
Also when I shaped the neck head joint I had an accident.
I was careless...
I was holding the head piece and chisel the joint for better fitting, the chisel slip and cut my thumb and plunged into my hand.
Luckily the plunged wasn't deep but the thumb was cut pretty badly...
(However, the plunge did more damage to my guitar playing as I can feel the weakness in the ring finger after the accident.)
I went to see doc and had the wound washed and bandaged.
Anyway I need to remember the hand is not a clamp...
20160923
My binding stock has arrived.
The walnut colour looks closer to the original than my existing rosewood stock.
And walnut is easier to bend.
Now ready for the binding process.
20161017
I managed to bind the body.
I was waiting for my stock of walnut bindings to arrive but when I try to bend the binding they broke...
There were too much run-out in the binding.
Then I use my current stock of IRW and they end up fine!
After that I use tape and rope to glue the binding to the body.
This body was much easier to bind than classical guitars
Before gluing the bindings, I had to reduce the height by quite a bit as they were too tall.
If too tall during the binding process the rope / tape will pull it skew and not sit square to the slot.
So I glue using hide and tape as I go along.
After all is done, I use rope to tighten the binding.
When the glued dried I removed the rope and levelled the bindings using block plane / scraper and sandpaper.
After that I remove all the previous finish using scrapers and sand the surface to be ready for finish.
But before finish I better glue in the head first.
20161021
I finally glued in the head.
The V-joint wasn't really well done so I parred the joint for a better fitting.
After that I check the fit and started the gluing process.
I have to make a caul for the clamp to hold as the angle of the head is different from the neck.
This caul will enable the clamp to be in line with the head and thus able to exert pressure correctly.
I also started to dissolve some shellac for the FP after that.
Head glued to neck and clamped. The caul is on the neck and has the same angle as the head so that the clamp can exert pressure correctly.
20161028
The head is fully secured.
Actually I am quite surprised by the result.
The joint is tight now, there used to be some gaps in the head / neck joint.
Unfortunately I don't have the picture to show this part.
Now it's tight especially the part where the V mortise sits on the triangular tenon's shoulder.
I also corrected the skew in the head.
Now it's parallel to the neck.
But I need to widen the nut slots as a result.
20180308
I began to apply the finish to the backs.
I am using dark blonde shellac.
Look at the nice orange hue.
Some more progress.
The orange hue is really nice.
As I had used brush to brush on the shellac, the look and feel of the finish is like a violin.
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