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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
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

1 comment:

John Brown said...

This is a common problem for all guitar players. I have an old Gibson guitar and I have to repair the Les Paul bridge part. The content is very informative as I have got the right way to repair the bridge problem. I want to repair the Les Paul bridge part by myself and after reading this article I have the opportunity to do that. Thanks for the article.