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Stronger than the original
Peghead Overlay
© Frank Ford, 11/12/99; Photos by FF, 11/99

Here's one of my favorite structural repairs. It's a "backstrap" overlay. No matter how bad the break is, this technique will result in a peghead that's stronger and more resilient than the original. It's time consuming, but rewarding. One important point I'd like to stress is the choice of a heat resistant glue, such as hide glue, for this operation. While this is a mechanical break due to a fall, it's important to remember that we have an opportunity to introduce a new element of danger -- heat. Here's a good example of what happened with a similar repair that was done with Titebond, one of the least heat resistant glues: Backstrap Overlay Heat Failure.

It's a bad break, all right. About as bad as it gets. This 1974 Martin D-18 suffered a serious whiplash injury as its case fell forward. The mass of six Grover Rotomatics added up to quite a bit of inertia. That, added to the string tension, was just more than the mahogany peghead could handle.

I can get the peghead to go back in place easily, but there's little hope of it being very secure.

In fact, if you look a the grain direction, you can see that it's a little less than favorable. The grain always runs off at an angle, but this is a bit more of an angle than usual. Also, notice the extra cracks that developed when the peghead broke.

I glued up those cracks first, so I could refit the peghead more easily. I have it clamped up between two acrylic sheets with waxed paper to avoid the acrylic being glued to the peghead with the thin viscosity cyanoacrylate. I chose the thin C/A because it would penetrate those tight cracks easily, and I'm not worried about messing up the finish.

Now, I have the peghead back in place. I slathered up the break with epoxy (to fill gaps left by a few missing pieces) and drove it on with a mallet, then clamped it with my acrylic sheets to keep everything aligned and flat.

To avoid running into the end of the fingerboard, I glued a piece of 1/4" plywood to the surface of the peghead. It made things easier to handle.

Here's the Wagner Safe-T-Planer in action. I used it to take a little more than 1/8" off the back of the peghead. I could have set up a drum sander and a fence, but I chose the drill press planer because it makes chips instead of dust (less messy) and because setup takes no time at all.

Here's the result. I've taken off about .150" from the back of the peghead. You can easily see the cracks. I could simply overlay the peghead as it is, but I'd be really asking for another break at the joint between my new wood and the old, just ahead of the first and sixth tuners.

I broke out my small drawknife and continued the cut around the bend in the neck behind the nut.

And down the back of the neck to a little past the first fret. The idea is to extend the reinforcement way down the neck so that any flexing of the peghead wouldn't crack my reinforcement loose.

Now to level up and smooth that transition. I used a hard, flat sanding block and checked from sided to side with a straightedge to make sure I kept things flat.

Of course, I measured the result to calculate the thickness of overlay I would need to bring the peghead back to the original dimension.

Here it is, ready for the reinforcing overlay. I have lots of gluing surface on both sides of the crack, so I'll be sure to make a solid repair.

Back to the Safe-T-Planer to make my .150" mahogany overlay.

Covering the back of the peghead with wide masking tape, I cut the shape with a razor blade.

And simply stuck my template onto my overlay material, and cut roughly 1/8" away from the edge to make a slightly oversize piece for my overlay.

Here's a venerable tool. It's a bending iron I got from Mario Martello almost 25 years ago. He was trying to retire from guitar repair (he still hasn't managed to retire yet) and selling off a few tools. Anyhow, I made a slight bend in the overlay to fit it to the neck. Pretty thick stuff for bending, and I scorched it a bit. No problem, though, because I'd be sanding that off later.

I wanted to use hide glue because it is incredibly strong, and won't creep or slide even in the high heat of a parked car. I simply laid my overlay piece on the cooling bending iron to warm it while I readied my glue.

Hide glue can't be clamped after it gels, so I worked fast and jammed on all the clamps I could find. I already had a clamping caul glued to the face of the peghead, so I didn't need three hands to do the job.

The next day, after the glue dried, I took my 1/4" plywood off the face of the peghead, clamped a piece of scrap to the back, and drilled the tuner holes through my new backside overlay.

My big violin knife made short work of trimming the mahogany overlay. Notice that I'm not actually cutting directly at my thumb, which I'm holding about 1-1/2" inches below the line of my cutting force. This "paring" grip gives me strength and control for my cut.

The little drawknife came in handy for roughing down the "tongue" of the overlay.

Here I'm using my left thumb as a fulcrum as I pivot the handle of the knife to make very strong controlled cuts to trim the tongue of the overlay. I didn't complete trimming the overlay yet. I just wanted to make sure that no overhanging pieces were left which could be injured as I worked on the other side of the peghead.

This is one of the heat blankets that come in the kit sold by L.M.I. All of the different shaped blankets plug into a timer so you can avoid burning things if you forget to watch the time.

The heat penetrated the face veneer in just a few minutes, and I was able to lift it right off.

In fact, the veneer came off very neatly indeed. It was originally installed with aliphatic resin wood glue, which is notoriously sensitive to heat. Here, that sensitivity worked to my advantage.

I made a piece of veneer of matching thickness, again using the Safe-T-Planer, and beveled the edge that would touch the nut. In fact, I held the nut in place to locate the veneer as I clamped it up

Cauls on top and back, I clamped my new veneer on with hide glue. This time I didn't have to worry about being able to clamp things in time because both surfaces are parallel and flat, so the clamps went on in a jiffy.

After the glue dried, I once again drilled through the tuner holes.

Then it was time to trim everything neatly. I used my low angle block plane to true up the edges of the peghead Perhaps I could set up a router device of some sort to trim things, but working by hand I get the job done is such a short time, I doubt I could set up any kind of jig more easily or faster.

Out comes my big knife to trim the end. Here's another piece of knife technique to observe. I have the palm of my left hand braced on top of the front jaw of the vise.

Using my left hand as the fulcrum, I press downward on the end of the knife handle with my right, and lift slightly with my left, keeping the heel of my left hand on the vise. I develop tremendous leverage this way, and can slice both the rosewood veneer and the mahogany overlay very neatly.

To finish down the tongue of the overlay, I used my knife as a planer, laying the broad bevel flat against the surface and shaving off little slices.

As I got closer to the final shape, I turned my knife over and used the back edge as a scraper, holding it with the "paring" grip.

For final leveling and sanding, I used a plywood block with a slightly rounded nose. My sanding was first with 150 grit, then final with 220.

The block was long enough to follow the profile of the neck and assure that I didn't sand a "hollow" area.

A flat, hard block finished off the end and edges of the peghead

My favorite little resilient block is the famous "Pink Pearl" eraser I used as a kid in school, still available in stationery stores. This little guy helped me resolve the curve of the veneer as it bent down the neck.

I used a little scrap of leather to back the paper for hand sanding as I cleaned up the rounded the neck area

OK, all done. Well, almost all done. Still have to do the finish. The overlay "feathers" out to a fine thin edge which simply cannot spring loose no matter how hard the neck is hit.

The overlay itself has perfectly straight grain with no runout, and the grain actually bends as it proceeds down the neck. So, there's no grain to split. Wood has extremely high tensile strength, so it's very unlikely that the peghead could be broken again in a forward fall.

All in all, it looks pretty good, too. Sure, you can see the overlay, but with a dark stained finish, it will not be objectionable.

The only remnant of the break are these little dark lines, one on each side of the peghead.

Time to touch up the finish. The owner of this guitar didn't want to refinish the entire neck, so my job was to try to match the stain and blend the finish only at the peghead First, I wiped on a coat of shellac to seal the wood, and to avoid having the filler stain too darkly in the end grain.

Next, an application of paste wood filler. Martin tended to use dark walnut filler on both mahogany and rosewood, so that was my choice, too.

Wiping the filler across the grain helps it stay in the pores.

Filler on, ready for some finish. I sprayed on a coat of clear lacquer to further seal everything, and allow me to remove the color if I didn't get the touchup stain right.

I airbrushed on some very thin lacquer with stain added. I didn't mask off the original finish, but simply sprayed right over it, too.

After the color coat dried, I took a sharp razor blade and carefully scraped my colored lacquer off the original finish. I've found this technique gives me the best chance of getting a decent transition between the old and new colors.

Here's the decal for the front of the peghead. It's printed on the paper upside down, otherwise it's a standard old fashioned water decal transfer.

I soaked it in water for a short while to release the decal. It goes on the peghead as soon as I build a bit of lacquer on the surface.

Once the decal was pressed in place I patted off the excess water. When it was good and dry, I continued spraying lacquer to build the full finish thickness, embedding the decal in the lower layers. The new wet lacquer melted the clear areas of the decal so they became invisible.

I completed the finish by spraying on clear lacquer, leveling, and ended with a coat of semigloss lacquer, just as Martin had done when the guitar was new.

From the back, the contours are the same as the original.

All in all, the stain does a pretty good job of disguising the repair job.

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