Trade Secrets!

How to fix this guitar if my elbow's stuck in the soundhole?


Issue 142 June 23, 2011

Image: Curious Dan How can I fix this guitar
if my elbow’s stuck in the soundhole?!

Dan Erlewine, June 23, 2011
Photo: Dan Erlewine
Image: soap barHey, it actually happened to me! Years ago I got my elbow through a soundhole, then couldn’t get it back out. No kidding. I had to soap my arm to get it out of there.
Try doing that one-handed, while your other hand has somebody's guitar stuck on it! I felt pretty silly as you might imagine, and this isn't something I’ve talked about very often. ;-)
And it almost happened again last week.
This classical guitar came to the shop because its top was buzzing. Looking inside with a light and mirrors, I found the problem. At the tail of the guitar, there was a gap between the top and the tailblock.



Photo: gap at the tail block Pressing on the top outside, I could see a gap open and close inside. It’s almost too small to see in this photo, but it’s there: the lining between the top and the side had come unglued. Flexible Lighted Inspection Mirror
Photo: classical guitar troubles
This guitar must have suffered quite a blow. On the outside, there was a “crunch” fracture along the binding, and a long crack heading toward the bridge. A bit of staining showed where someone had tried to fix the crunch, and a light area along the crack was probably from their sanding.
Their glue at the binding held tight, but clearly the seam inside needed regluing. I couldn't get at it by wriggling my arm into this classical’s small soundhole. My arm was getting stuck, and no way was I going to go through that again!
Doing an inside job from the outside
Even with my fancy repair gizmos, I couldn’t maneuver well enough to get glue where it was needed, much less complete the work before the glue started to dry. Even if I could, my glue job would be sloppy as heck and hard to clean up. I decided to “think outside the box” by removing a section of binding to access the loose joint and get at the problem.
Photo: routing The wood binding had multiple layers divided by thin strips of maple. I used a ball-bearing binding router bit to remove the outermost layer of rosewood binding. I left the intricate inner laminations untouched. Removing the rosewood was enough to give me access to the joint.
Binding Router Bit Set
Photo: feeler gauges Now I could slide feeler gauges into the loose joint along its entire length.
I used the feeler gauges and an offset disassembly knife to apply Titebond glue to the joint. I drilled holes in the offset disassembly knife so it holds more glue. You might remember the small inset photo from Trade Secrets #104 which introduced this "swiss-cheesey knife" idea.
Offset Disassembly Knife
Photo: spool clamps With the glue in there, I clamped the joint shut with spool clamps: cork-padded dowels sliding on all-thread rods. The plastic straws protect the guitar's finish from the threads.
While this dried, I got ready to replace that section of rosewood binding I routed away.
Spool Clamps
Photo: bending iron I cut a strip of rosewood to size, soaked it in water for 30 minutes and bent it to shape on a bending iron.
Image: Dan goin' to bedAt this point, I left everything to dry overnight and went upstairs to bed.
Bending Iron
Photo: rosewood binding patch Day 2: covering my tracks
The next morning I shaped the ends of the rosewood strip to match the curves left by the router bit on each end of the routed ledge.
Now I've got a nice rosewood patch for concealing the site of my "surgery."
Franklin Titebond Glue
Photo: rubber binding bands I glued the strip in with hot hide glue, using rubber binding bands to clamp it in place.
Rubber Binding Bands
Photo: razor blade scraping When the binding was dry I filed, scraped and sanded the new wood flush with the back and sides.
Natural Wood Bindings
Photo: classical string tie Anxious to hear if the buzz was gone, I strung the guitar to pitch before touching up the finish.
Notice how the bridge tie-block has two holes for each string: the string goes though one hole, then back over the tie block and through a second hole before being tied-off. I’ve only seen this style of bridge on a couple guitars.
Classical Guitar Bridge
Photo: Curious Dan No buzz!
And I never even had to monkey around in the soundhole!
Later on, after letting the glue cure for several days, I would touch up the finish with a little French polish.
Problem-solving products for this kind of work:
Offset Disassembly Knife
Offet handle protects the soundboard when lifting a bridge or fingerboard, cleaning glue from a loose brace, or for similar tasks.
Bending Iron
Controlled heat bending form for guitar, mandolin, violin and dulcimer sides.
Spool Clamps
Available in two sizes, spool clamps are fast, safe, and indispensable in your shop.
More More More
Rubber Binding Bands
The fastest way to hold binding in place while gluing.
Franklin Titebond Glue
The luthier's favorite aliphatic resin glue, for joints that are stronger than the wood.
Binding Router Bit Set
Cut clean, precise ledges for any practically any binding combination.
More More More

Don't miss an issue!

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