Acoustic Guitar Uhoh…Oahu!
It’s a laminate top with a bolt through each wing of the bridge. As the top relaxed over time, the bolts fought back and cracked the bridge plate and the top. You can see the top belly in these side shots, with the bridge leaning at an unusual angle.
In the shot below you can really see how the bridge torqued the top and cracked it in half.
In this one you can see the crack in the top itself, just to the left of the bridge wing. It’s like this on both sides.
When I took a look inside, things didn’t improve. The bridge plate looks like pine or something similarly soft. It’s cracked right at the bolts, and the stringballs are working their way through the top. Also notice the grain orientation. It’s going perpendicular to the strings, making it easier for the tension to split it in half.
So I dove in and pulled off the bridge off.. it didn’t take much.
Now the bridge is off, here’s a fun shot of a light inside the guitar illuminating the long crack in the top.
So now i’m going to try and remove the bridge plate and put on a strong new one to try and help out the top.
The first part came out easily. The back part was stubborn. I used a variety of bent scrapers and files to pull on the back edge.
After a while the plate let go, but it left behind a pretty uneven surface. I could use a block and some sandpaper to clean it up, but I just don’t feel like bending my wrist around like that. Luckily for me, Frank has a fun tool for this purpose.
This is Frank’s magnet sander. The disc in my hand has a very aggressive coarse surface, with four rare earth magnets inside (notice the dark circles). The other part is an acrylic base with a rotating internal system of magnets that match the sander. This part gets mounted in a drill and goes on the top surface, while the sanding disc goes on the interior surface and spins away.
The really clever part is that the acrylic doesn’t spin on the outside surface and scratch it up.
It’s a little hard to describe, here’s a video of it in action.
After the inside was sanded smooth, I glued in a new maple bridge plate and got a good amount of glue in the top crack. Then I glued the bridge back on and strung it up.
Ready to go!