Resurrecting a Hopelessly Damaged Gibson LG-2: Part 5

Hello again readers! I return to bring you the latest in the saga of the Gibson LG-2. As you will recall, last time, we got our hands dirty and removed the back’s binding and the back, so we could more easily access the top braces. If you’re new to this series, I encourage you to start form the very beginning:

http://www.guitarmakersonline.com/resurrecting-a-hopelessly-damaged-guitar-part-1/

…so you can see how we arrived at this point in our story.

As I’m sure you remember, I left off last week with the back binding and backplate completely removed, and I had just begun to investigate the horrors that awaited us inside the box. You probably even remember the picture, if you were paying attention at all:

X-Brace Problems

Here’s how I approached my investigation: I knew just from looking at the top of the guitar, way back in the first article in this series, that the x-brace had failed, and from looking with a mirror and feeling around, I also knew that the tone bars behind the bridge were completely missing. Also, from the way the top was buckling at the waist, I knew that the side strips had failed.

I had originally intended to attempt a guerrilla-style quick and dirty fix to this obviously flood damaged instrument, leaving the back on and gluing it up just from the sound hole, but the more I thought about the tone bars, the more I realized I was going to have to bite the bullet and remove the back in order to fix this thing the right way.

So when I finally got the box open, I grabbed my trusty thin bladed palette knife and started to find the areas where the braces were no longer making contact with the top. Here were the areas I found, where the blade of my knife passed easily under the braces:

...Another X-Brace Problem Area

Third Problem Area, Same Brace

Same Brace, Opposite End...

Problems with the Other X-Brace...

...Even More Problems at This End

Each arm of the x-brace was WAY off the top in those key areas that provide support. As I’m sure you have gathered, the function of the x-brace is to keep the top stiff while under string tension. It counteracts the force applied to the areas just in front of and behind the by the string tension, and keeps the buckling (in front), and bellying (behind) in check.

I could also see areas where the transverse brace was not glued down, especially in the center. Where the braces got close to the sides of the guitar, I gripped them between my thumb and forefinger and tried to move them…some gave slightly and I could feel the telltale wiggle…

More Space Under the Transverse Brace

 

Gluing braces turns out to be really easy with the back plate removed. Just put some glue on either side of the palette knife, push it through, remove the excess glue, clamp it up, and leave it for at least 2 hours to dry, 24 before you stress it. Care must be taken to avoid marring the top with the clamps, so cauls or leather protectors or flat pieces of wood that spread out the clamping pressure are required.

Using the Knife to Apply the Glue

Applying Glue to the Other Side

Clamping the Center

Removing the Squeeze Out

The Gluing Arrangement

The Result

Continuing the X-Brace Gluing

More Glue Along the Length of the X-Brace

Clamping And Removing the Squeeze Out

 

Applying Glue to the Second X-Brace

Clamping the Second X-Brace

 

One Clamp at the End of the First X-Brace...

Two Clamps at the End of the First X-Brace

Clamping the End of the Second X-Brace

I also found that the finger braces were loose. So I attacked them the same way: glue the knife, smear, clamp, remove squeeze out…

Finger Brace Space

Gluing and Clamping the First Finger Brace

View of the First Finger Brace Caul

Clamping and Gluing the Second Finger Brace

View of the Second Finger Brace Caul

After the clamps and cauls are removed, it is a good idea to check your work. I checked mine by tapping the top in the problem areas and listening for the rattle that betrays the loose brace. I find that the tapping is really useful for detecting braces that are loose at their edges, by the sides.

In the case of this guitar, I’m glad I did the tap testing because I found a loose brace that I wouldn’t have otherwise checked. I got the rattle when I tapped the top on the upper bout on the bass side and also when I tapped on the treble side near the tongue. When I used the thin knife to investigate further, I found that the flat upper strap and the transverse brace (which I had forgotten about) were, indeed, not attached to the top. Again, I applied glue to both sides of the thin bladed palette knife,  slid it precariously under the offending braces, got some clamps and cauls, and left it all to dry for a few hours.

Rattling at the Transverse Brace

 

Rattling at the Strap

 

Gluing the Transverse

Gluing the Strap

The View From Below

Next, I had to decide what to do about the tone bars…I really didn’t have any great ideas…my first idea was to use the cheapest pre-dimensioned strips of wood I could find, and shape them to the correct radius and scalloping. There were lots of problems that I found with this approach.

First of all, the cheapest pre-dimensioned lumber I could find turned out to be balsa wood, not surprisingly. Balsa wood isn’t the best wood to make braces, as it is a little too soft and pliant.

The second problem I had I have been articulating throughout this series. I don’t really know what the top’s radius was, and I had a really hard time trying to figure out what the top radius was using the traditional channels on the internet and even asking the best luthiers in my town, Nashville, Tennessee. No one knew unequivocally. With that fundamental ignorance, even if I had the properly dimensioned lumber, I would not know which radius dish to buy to use to sand the wood to that radius…so I was stuck…again…for a while…UNTIL…I decided to try something: Stewart-MacDonald offers sets of braces that are pre-shaped and radiused to the shape and radius of a traditional Martin dreadnought guitar. I had a hunch that the radius of a dreadnought was pretty close to our LG’s radius, so I bit the bullet and ordered the top brace set…and secretly hoped that I didn’t just waste $24…I was also worried that the tone bars is the set would be too long to fit this smaller bodied guitar. So much worry.

When the braces arrived, I immediately found the tone bars and placed them on the top…to my delight, the radius and thickness were perfect, I just needed to trim the ends so they would fit properly. I put my trusty band-saw on top of my bench and went to work.

Pre-Shaped Braces

Where the Tonebars Go

Fitting the Bass Side

Fitting the Treble Side

Tonebars Marked

Cutting the Tonebars to Fit

Test Fitting Tonebar #1

Test Fitting Tonebar #2

For authenticity, it’s important to make the braces sort of fit TERRIBLY, as if you were a worker in a Kalamazoo factory in about 1957 and you had 30 tops to brace today, and it was cold as hell and you were smoking and breathing lacquer fumes and inhaling huge qualities of rosewood and bone dust, and you were probably hungover or still drunk…

So after I cut these braces to length (more or less), a and filed off the tear out at the ends, I started to think about gluing them in.

It seemed to me I needed to have at least three, possibly four clamping points to get the brace glued to the top effectively. I started with the tone bar farthest away from the bridge, because I thought it would be easier to remove squeeze out that way. I used one cam clamp in the middle of the brace, being sure to use a caul, so I wouldn’t mar the top. Then I used a long reaching C clamp for the side of the brace on the far side, and used a piece of maple to extend the reach of my cam clamp on the near side. I did a quick dry fit, then applied glue to the brace, and clamped it up, then I let it sit for 24 hours.

Dry Clamping Tonebar #2

Applying Glue to Tonebar #2

Gluing Brace #2

Tonebar #2 Glue Dry

The next tone bar went exactly the same way:

First a dry fit, followed by the application of glue, followed by the clamping and the drying.

Tonebar #1 Glued Up

 

With those all glued on and dried, it was time to move my attention to the bridge plate. The original is a thin, ill-fitting piece of maple.

The Original Bridgeplate

I found some scrap maple sitting around the shop, so I traced the original bridge’s dimensions on it…but then I noticed that on the original bridge, the bridgepin holes were closer to the edge of the bridgeplate than I thought was acceptable, so I added a few more mm to the front of the bridgeplate to make it a little more substantial.

Laying Out the New Bridgeplate

Out came the bandsaw again, to rough cut the bridgeplate, followed by a few quick passes with a sanding block.

Cutting Out the Bridgeplate

Test Fitting the Bridgeplate

As before, with the braces, you start to notice the weird quality problems Gibson used to have…in a Martin from a similar era, the bridgeplate would be a huge thing, tucked under the X brace legs and extending almost to the first tone bar. This Gibson one wasn’t touching the braces anywhere, no finessed tucking and angling of the bridge plate: just a small, thin trapezoid of maple.

Next, I got my cauls out, smeared some glue on the bridgeplate, and glued it to the top, letting it dry for 24 hours.

Gluing the Bridgeplate

Top Side Bridgeplate Clamping Caul

Notice the waxpaper on the caul, to keep the glue from attaching the wooden caul to the top (yikes!).

Here’s the effect all of this regluing and replacing of the braces and the bridgeplate (with a few extra holes we’ll get to next time):

The Results of All That Clamping...

If you will recall, when I first acquired this guitar, the areas behind the bridge were lifting, or “bellying,” and the areas just in front of the bridge were starting to buckle or “cup.”

Now, the belly is far less severe, and the cupping in the waist areas beside the soundhole was almost totally alleviated.

Flattened Belly

Next, I did a fairly straightforward bridge reglue. First, a dry run with the clamps and cauls in place, then the smearing of the glue and the real glue up, left to dry for 24 hours.

Dry Bridge Clamp

Glue on the Bridge

Clamping the Bridge

Another View of the Bridge Glue-up

Here is the final result:

Bridge Installed

Much Better...

As you can see, it’s looking a lot more like a guitar now.

Next time, we’ll revisit the horrors of the back and the braces we have to build…and finally get to plugging and re-drilling the peghead.

Stay tuned! It’s about to get REALLY interesting.

 

 

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