10/15/2016

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!

1 comment:

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
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