Trade Secrets!

Christine's inexpensive guitar needs a bridge repair: fix it or pitch it?


Issue 141 June 09, 2011

Image: Fix it or Pitch it?
Photo: Christine's bridge repair A simple bridge repair
Should Christine do $100 worth
of repairs on her $160 guitar?

Erick Coleman, June 9, 2011
Photo: Christine Christine works the front desk at StewMac. She recently bought this acoustic for playing around the house. The guitar sounds good, and for $160 it was a good deal, too.
Photo: gap under bridgeChristine noticed this gap under the back edge of the bridge, showing that the bridge was coming loose from the top. This is pretty common; bridges pull up for lots of reasons. Heat can be the culprit, or maybe the bridge was glued to a finished top instead of bare wood, preventing good adhesion. We can't know this bridge’s story without taking it off to look.





“Pyramid” Guitar Bridge
At this point, I had a “Fix it or pitch it?” talk with Christine. At United Lutherie, the shop I share with my pal Gene, a repair like this starts at $75 and goes up from there depending on what other issues are present. Bridge re-glues are bread and butter jobs, and we see a ton of them. But sometimes customers have a tough time swallowing the fact that the repair could cost more than half the guitar’s purchase price:
Why should I pay $100 to fix this?
I can buy a new guitar for $200!
Well, the bridge is likely to pop
off your next bargain guitar, too.
It happens all the time...
Photo: bridge heaterAnyhow, I'm biased: I don’t like the idea of guitars in dumpsters. Christine opted to fix it, then her curiosity kicked in: she wanted to watch the repair. It’s such a basic job that we decided it'd be fun to have Christine do the work herself, while I supervised.
On a hotplate, she heated the bridge heater to around 400 degrees and moved it around the bridge surface, slowly heating the entire bridge. Periodically reheat the caul (or use two, heating one while using the other) and keep it moving. Don’t linger long enough to scorch the wood.
As the glue softened, Christine slowly worked the removal knife under the bridge from a variety of angles.
Bridge Heater and Fingerboard Iron




Bridge/Fingerboard Removal Knife
Photo: bridge removedWith the bridge off, you can see what the issue was. The manufacturer simply didn't use enough glue to hold the bridge on in the first place. Note that there's no glue coverage at the edges.
This bridge came off easily, bringing a few splinters of wood up with it but nothing too bad. It’ll go back on nice and clean.
With some scraping and warm water, this remaining glue wiped off the bottom of the bridge.
Photo: masked offPrepping: A chisel removed any glue left on the guitar top, then Christine masked around the gluing area. With all surfaces clean, she used a micro chisel as a toothing file to give the glue a little more to bite into (below).
Franklin Titebond Glue
Photos: toothing the bridge surface Micro Chisels
Photo: spreading glueGluing: Christine used a brush to apply plenty of glue to the bridge and the guitar top. I might have used hot hide glue, but chose Titebond for its lengthy working time: on Christine’s first time out, no sense making her race against time.
Glue Brushes
Photo: glue cleanupShe used the two E string bridge pins to position the bridge, then pressed down firmly to squeeze out as much glue as possible. A damp rag wipes it away.
Bridge Plate Caul
Photo: bridge clamping Soundhole Clamps
Using soundhole clamps and a bridge plate caul (to protect the bridge plate and spread the clamping pressure), Christine clamped the bridge in place. While tightening the clamps, she again wiped away glue squeeze-out and cleared excess glue out of the bridge pin holes.
Image: big images on Facebook
Photo: bridge clamp cauls The grooved soundhole clamp cauls work great for clamping pyramid bridges like this one. The grooved recess settles nicely over the peaked shape.
Soundhole Clamp Cauls
Photo: clamped up Clamped up. We let this sit overnight. When I came in the next morning I removed the clamps and cleaned up any dried glue with a warm damp rag. Everything looked great!
Photo: fixedThis bridge is fixed, and the guitar’s ready to go home to Christine.
Photo: Christine has her guitar back! Reunited! After stringing it back up and double-checking the setup, I dropped the guitar off to her at the StewMac office. Now Christine's back in business — and she’s learned a thing or two about guitar repair, to boot!
Problem-solving products for this kind of work:
Franklin Titebond Glue
The luthier's favorite aliphatic resin glue, for joints that are stronger than the wood.
Bridge Heater and Fingerboard Iron
Softens glue for fingerboard and bridge removal.
Bridge Plate Caul
A non-stick plastic interior guitar clamping caul for gluing a bridge or a bridge plate.
More More More
Glue Brush
A versatile metal-handled brush that's the right size for routine instrument gluing jobs.
Micro Chisels
Set of four model maker's chisels, for trimming nut and saddle slots or for removing dried glue around braces and frets.
Soundhole Clamps
Ideal for clamping bridges and braces through a soundhole, these clamps reach where others can't.
More More More

Don't miss an issue!

Get Trade Secrets delivered to your inbox. Only from StewMac.