Monday, September 17, 2012

Vintage Harmony ukulele: replacing a broken bridge

This is sort of a good news/bad news post.  The  good news is that the original tuning machines on this Harmony uke didn't need to be replaced as I originally thought.  They just needed a little tightening up.  The bad news is that when I went to string this sucker up, I heard a brief cracking sound and then a very loud SNAP!  The front part of the bridge must have had a crack that I couldn't see and it gave way under the tension of the strings pressing down and ever so slightly forward on the saddle.  But I guess it's not all that bad...at least now I get to show you
how I replaced this broken bridge.  Although I feel like this is sort of like an episode of Tool Time on Home Improvement where Tim accidentally screws up the project and then explains to the viewers that he did it on purpose to better educate them.  Hmmm.....

A word of caution:  I am sure that there is a far more precise way to go about this whole procedure.  This is just how I was able to make it work.  I would never attempt this on a more expensive ukulele and you probably shouldn't either...if you have a uke that is worth something, please take it to a luthier and don't damage it further.  But...if you have a cheap one that you don't mind experimenting on, have at it!  Worst case scenario, you screw it up and learn what NOT to do.  


Before I ever attempted to remove the bridge, I used some painter's tape to mark the area where the new bridge would sit.  Two reasons for doing this -

1. I wanted to make sure that the new bridge sat the same distance from the 12th fret that the old bridge did.  If it was further or closer it would affect the intonation of the instrument.

 2. I wanted to prevent the new bridge from sliding around and getting out of position while it was being glued.
 As you can see in the 2nd picture, there is a bit of space between the tape and sides of the bridge.  The new bridge is a bit wider so I measured and extended for the width of the new bridge.  I used 7-10 strips of tape layered on top of one another to create a wall of tape that would hold the new bridge in place while being set.  I'd recommend painter's tape for this since it holds well and comes off easily without damaging the finish of your uke.


There are a number of methods that can be used to remove a glued bridge.  Everything from using a heated pallet knife to taking a chisel to it.  Here's how I approached it....
1.  The first thing that I did was run a hair dryer over the old bridge for about 5 minutes.  My thinking was that the heat would help to loosen the glue that was holding the bridge, thereby making it a bit easier to remove. 
2.  Next I took a flathead screwdriver (I don't own a chisel) and very lightly tapped off bits of the old bridge starting from the top.  This worked out pretty well...just took awhile.  I decided that rather than trying to simply separate the bridge from where it met the body, that it would be better to take it off in small bits in a layered fashion.  Of course, if you are hoping to keep the broken bridge intact this won't work for you.
3.  When I got close to the body, I just continued the process until it looked like this 3rd picture.  I was hesitant to "chisel" any further toward the body and decided that this was close enough.  In this picture you can see that there are small pieces of the old bridge that remain, but they came off easily when I sanded the rest flat.


Once I got it to the "close enough" point, I just sanded off the thin layer that remained of the old bridge, as well as the old glue (I used some 220 grit sandpaper for this).  The final result looked this.  For being a highly imperfect and imprecise method, it worked out pretty well!
After I was satisfied, I used a damp cloth to clean the surface of any particles and let it dry for a bit.




I used Titebond wood glue for this.  As you can see, the new bridge fit into the tape barricade nicely.  Also want to mention that you can strengthen your bond by putting wood glue on both surfaces.  In this case, on the bridge and on the body.








I try to have a few things handy when glueing.  A small dish with some water and a sponge make cleaning up excess glue A WHOLE LOT easier!  Whether you need something to clean glue off your fingers or to dampen a paper towel with, keep it by your side.




I also like to keep some toothpicks and paper towels handy for the harder to reach spots.
You can wrap a toothpick in a small piece of paper towel, dampen it on the sponge, and Voila!  Now you can clean that excess glue away from the crevices that you could never seem to get to before. 




On to the clamping.  My F clamp barely reached far enough to hold this bridge.  On ukuleles with longer/wider bodies, you might be in for a bit of a challenge.  Stewart Mac sells these sound hole clamps that are definitely worth the cash.  I need to get one!  I've also seen people that just use a cinder block to hold it down during the "clamping" process.  I'd be hesitant to try that method.



After I had the clamp firmly in place I let it set and adjust for about 15 minutes and then proceeded to peel off my spot marking tape and finish cleaning up all the excess glue around the new bridge.
...and another clamping picture.  The unfortunate thing about this repair was that the new bridge was not as long as the old bridge.  The result is that you can still see where the old bridge used to sit.  Oh well, beggars can't be choosy.
Oh yeah!  Before I forget, a new bridge can readily be found at  Stewart Mac, Ebay, or a variety of other places on the web.  The Stew Mac bridges look really nice, albeit a little pricey.



And there you have it!  All ready to go.  I clamped it for about 4 hours.  After that period of time, you should be able to go ahead and string it up, although I usually let mine sit overnight before I put strings on.







All she needs now is a new set of strings and a light set up.  We'll get to that in the next post.  I hope that all this bridge replacement information has been helpful!

2 comments:

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    1. You are most welcome! I just hope it all might be of some help!

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