Workshop: New Bridge Pull-Off?


This, of course, is why the bridges come off so rapidly on newer guitars. Do you see how only a center portion of the bridge was actually glued to the top? The outside 1/8" of its footprint wasn't even glued as the factories spray their tops before fitting bridges. This is common to most every modern factory-built guitar these days and even applies to this one -- a quite high-end, 10-year-old Martin.

The downside of this practice is obvious -- you're losing a major amount of gluing surface. It's effectively turning the improved footing of a "belly bridge" into the smaller footing of the old "rectangle bridge."



The first part is to prep the surface. I mark the bridge's area with a pencil and then use an angled chisel or x-acto knife to slice through the finish. I chip the finish off and then use sandpaper to get down to wood.


After that I take the bridge over to my belt sander to remove any glue remnants and use my trusty StewMac bridge regluing jig to clamp it all down to the top. I have a bit of hardwood I use under the bridge plate to apply clamping pressure to.


Unfortunately the aluminum bridge gluing jig is excellent except for when you're dealing with a top that's lightly domed or distorted and the extra "back" of a belly bridge. For that I use smaller clamps and a block of wood to apply pressure directly to the rear of the "belly" and snug it to the top. If the block wants to slip I c-clamp it to the gluing jig just to hold it in place. This c-clamp is way overboard but I'd used-up all my smaller clamps on other projects at the moment!

Comments

Robert Gardner said…
It's great to see your careful work on that Martin, Jake and sad to see all the top real-estate that didn't get glued in the factory because of the finish. I guess it saves them 5 minutes of assembly time per guitar or something, but I knew when I saw daylight under that bridge that the boys in Nazareth had done that old OM-42 wrong... I wonder if having the full surface bridge glued more thoroughly will improve the tone at all. Couldn't hurt... Thanks for the quick turnaround on the bridgectomy
...