Gibson L-30

Repair Job

An interesting vintage guitar - a Gibson L-30 flatback archtop probably from the 1930's. If all original and in good condition, these go for about $2,500 on Reverb. This one is not in great condition but comes with the original parts which are generally intact. There are some cracks that need repair, loose binding, re-fret and refinish etc. The original tuners may have to be replaced with more functional ones. An interesting project. The guitar belongs to Matt Reeves of Reeves Art and Design in Montrose, Houston. I agreed to doing a repair /restoration with the primary goal of making it functional while keeping it as close to original as practical.

Current Condition

It's difficult to say what the original finish on the guitar was, probably lacquer on top of stain. The most recent 'finish' is a varnish/stain. This was crudely applied with a brush all over the instrument - tuners, fretboard, binding, nut etc. Testing with alcohol and acetone determined that it was not lacquer nor shellac so it's probably an oil-based varnish. There is a split/crack in the top along the center join and a small split at the location of the forward pick-guard screw. The binding is separating from the body in places.

To start with I scraped and sanded most of the varnish off.

Binding Repair

One of the challenges of repair is the risk of attempting a fix which results in making matters worse. The original celluloid binding is, for the most part, intact with one area of significant separation and a couple of smaller ones. I suspected that it would be fragile if I tried to loosen the binding, clean out the channel and reglue it. If this didn't work it could easily escalate into a rebinding job.

After cleaning out the channel I gently heated the binding to soften it then glued, taped and clamped it back in place.

That worked well. I repeated the process for a couple of smaller loose areas and used acetone to fill in a small break in the binding.

Split in soundboard

There's a fairly significant split in the archtop. Part of it is separation along the join between the two halves but in places the crack has run along grain close to the join.

A crack like this would compromise the guitar's acoustic potential. The energy from the strings is transferred via the bridge to the soundboard which resonates to produce volume and tone. I'd like to get a good solid repair in place here.

The crack is probably too wide to clamp and glue, besides clamping would require putting significant pressure on the sides which are probably about 0.090" thick. I made a couple of cauls to spread the clamping force over a broader area. The two wooden cam clamps are pressing down on the soundboard to help close the gap.

Even with this force applied the crack is still not closed so it cannot simply be glued together. After a visit to Neil Sargent I decided to use a combination of clamping, cleats and wooden slivers to seal and glue the gap.

An F-hole soundboard does not allow for access to the inside of the guitar so gluing cleats to the underside is tricky.

I made some circular cleats. These are cross grain laminated since I won't have control of grain alignment when I glue them in place. The photograph above shows where I intend placing them inside the guitar.

The next step involved making a couple of small jigs or jacks to help get the cleats in place.

These are made from some scrap wood and spare tuners. The technique involves threading a guitar string through the crack, out the f-hole and through the cleat. The string is looped so it can't pull through the cleat and twine is attached to the loop so the string can be retrieved.

Since I hadn't done this repair before I started by gluing a small cleat at the location of the crack beside the fretboard near the neck block, associated with the pickguard mounting screw. That worked well. Here's a photo of the cleat in place, taken with an endosope camera.

Even with clamping and cleats the crack would not be fully closed so I shaved some slivers of spruce off a piece of scrap guitar bracing and prepared to shimmy these into place during the gluing process.

Here's what the cleat assembly looks like.

Time for assembly. Glue is squeezed into the crack. Spruce slivers are slid in where there are gaps. The clamps are tightened, The cleats are glued and pulled into place then tightened up using the tuner jigs. When the glue has hardened the guitar strings are cut and the twine is used to retrieve the section inside the guitar.

Here are a couple of photos of the cleats in place after the glue had hardened.

Here's the crack after repair. The light colored slivers of spruce are evident. They will darken some over time although I may have to figure out a way to make them less obvious when applying finish. I'm satisfied with the structural integrity of the repair.

Fretboard and Headstock

The whole guitar had been crudely coated with stain/varnish, including the fretboard and headstock. Lower frets and that section of fretboard showed a fair amount of wear.

I thought I might get away with a partial refret, however scraping the varnish off between frets didn't produce a satisfactory outcome so I decided to do a full refret. Removing all the frets would allow the opportunity to clean up and level the fretboard. Scraping the varnish off the headstock exposed the two 'ears' which had been glued on to give the neck blank the necessary width so I made a veneer from some Indian Rosewood and inlaid a logo using the same font as in Matt's Gallery's logo.


The plan is to use original parts where possible. The truss rod cover was broken at one of the screw holes so I made a new one from a scrap piece of ebony, laminated with a veneer to prevent splitting.