wood-bending

Headstock Repairs - Reinforcement

Broken Gibson headstock repair

We've talked a lot about neck resets over the last few weeks so let's move down the other end of the neck. Headstock breaks.  

Nobody likes to see it happen but sometimes your guitar takes a tumble and the impact can—all too easily—snap the headstock. In most cases, this is a (reasonably) straightforward repair and can be re-glued soundly.  

Sometimes, though, the nature of the damage can force us down a more 'involved' path. If the break is 'short' (i.e. it doesn't provide a lot of glueing area to ensure a sound repair) it may be necessary to consider some reinforcement to ensure the repair holds.  

One solution is what's called a 'backstrap overlay'.  

This involves overlaying some fresh wood over the repaired break. The new wood glues onto the unbroken wood either side of the crack to add strength.  

Let's take a look at one. 

Reglue headstock before applying backstrap

Remove wood to accept overlay

In the first photo directly above, I'm repairing the break. This might seem odd but I need to get everything back together properly before I apply any reinforcement. The repair is carried out as it would normally be since the actual re-gluing isn't the real problem—the problem is keeping it in one piece after string-tension is applied. I need to glue-up everything as normal and then reinforce things to ensure the repair is strong.

When the initial repair is done and the glue has dried, I can begin the real work on this one. I remove a few millimetres of wood from the rear of the headstock and, past the break, along the neck. It would make for a more discreet repair if I brought this all the way to the end of the headstock but, on a Gibson, I like to stop short of the serial number. If the guitar is ever sold on, a perspective buyer may be put off more by the lack of a serial number than a well-executed repair. 

The photo above on the right shows the removed section. I'll inlay the new wood here so let's get on with that.

Clamping for backstrap overlay on Gibson neck break

New wood overlaid over broken neck

The wood to be overlaid on the headstock is thicknessed and cut to the rough dimensions. To accommodate the angle between headstock and neck, I bend the new wood. It's this bending that adds extra strength to this repair as the wood grain curves to the correct angle.  

Repairing guitars often makes for some intricate clamping setups and overlays are prime culprits. A shaped caul is useful to get the wood in that curved bit glued in properly. The roughly shaped wood overlay is pretty obvious (and pretty ugly at this stage) in the photo on the right. 

Newly inlaid wood cut to shape on headstock

Tuner mounting holes drilled in overlay

This is where things take shape (pun intended). The overlay is cut to shape and the tuner holes drilled.  

At this point I can go through the usual finish prep. Grain-filling, sanding, etc. In cases like this I need to match the colour of the original finish on the newly overlaid wood. I also have to manage the transitions between new and old finish carefully to keep things looking as inconspicuous as possible. Sealer, colour, and a number of clear-coats later and I'm ready for the next step. 

Waiting.  

Have to wait for the finish to cure properly. Then sanding and buffing and polishing and reassembling and stringing-up and… 

Playing. 

All is well with the world.  

Gibson headstock break repaired with backstrap overlay

Les Paul neck repair with reinforcement

Reinforcing A Broken Headstock

SG Broken Peghead Repair

A while back, I outlined a (slightly) unusual method of repairing the broken neck of a Gibson SG. I mentioned that guitar would make another appearance soon and here it is. The guitar suffered a broken headstock while still in its case. A neck-break in the case was the final straw for the owner—who's had more than one Gibson require a neck repair— and he wanted to consider options to help prevent it happening again. We talked over the pros and cons of the various solutions and eventually decided on a backstrap overlay.

This methodis sometimes used where the break is too nasty or offers insufficient glueing surface to guarantee a sound repair. A backstrap was not a necessity to repair this particular break (and, indeed, it entailed additional expense to carry out) but the owner wanted to do something that would go towards preventing a reoccurrence.

Illustration of backstrapoverlay

Illustration of backstrapoverlay

A backstrap overlay involves removing some wood from the rear of the headstock and some way past the broken section. A patch is cut from new wood and is bent to conform to the curve between headstock-angle and neck. Because the inlaid patch has been bent to shape, its grain has no run-out and remains strong.

I explained to the owner, and I will to you, that this offers no guarantees. However, this method of applying bent wood certainly strengthens a weak area of the guitar and it will be stronger than the original.

Backstrap peghead repair
Headstock repair backstrap overlay technique

The first thing that needs to be done is to repair the existing crack. I've discussed this in a previous post so I'm not going into any detail here. A repaired crack is necessary so that the section to accommodate the backstrap can be removed. My usual preference, when doing this, is to run the strap right to the end of the peghead as the inlaid wood is more discrete. In this case, doing so would have removed the serial number and 'Made in USA' stamp and I decided keeping these better served the future value of this guitar.

A 3mm section is removed from the back of the headstock. The Saf-T-Planer allows me to do this cleanly right up to the point the neck angle gets in the way. The remaining section along the neck is removed with hand tools.

Bending wood for broken guitar neck repair
Repair patch for broken headstock

A piece of mahogony is thicknessed to the appropriate size and cut out roughly to shape. Out comes the trusty bending-iron and I work the wood into a gentle bend to conform to the section I've cut in the neck.

Clamping backstrap overlay on broken peghead repair
Reinforcing weak neck on Gibson SG

Some inelegant, but effective, clamping and glueing and the backstrap is in place.

But it's not pretty. The patched in piece does allow you to get a look at the bend clearly though. Because the grain in that patch (backstrap) runs—uninterrupted—from end to end it's much stronger than the piece that was removed.

Neck repair on Gibson SG
Completed SG headstock repair

A little work with routers, drills, knives and sandpaper and the new piece looks a little more like a headstock should. Some touch-up work helps hide the evidence. A (relatively invasive) repair like this can never be completely invisible under a translucent finish but this is pretty discrete.

We've repaired and strengthened a broken-necked SG and preserved the serial number. Not a bad few day's work.

Cross-posted to Guitarless

Wood-Bending for Fun and Guitar Repair

Acoustic Guitar Repair

An acoustic guitar with a dodgy, onboard preamp that had to be replaced. What should have been a straightforward job became a little more complicated becauset the original preamp had a particularly large footprint. It was an older, discontinued model and the manufacturer was unable to supply a replacement that was as large. As it turned out, it was pretty difficult to find any manufacturer that had a unit that would cover the existing hole (and patching and recutting wasn't favoured for cost reasons).

After quite a bit of internet rooting, a unit was found that would cover the hole in the guitar's side. Great.

Just one problem though… Although the bezel covered the hole, the mounting screws were located such that the front two had nothing to screw into (see the locations marked on the blue masking tape).

Guitar Repair - Acoustic side patch
Guitar Repair - Bending wood for side patch

The solution: glue in some wood for the screws to mount in. As this is the shoulder of the guitar though, the wood patch needs to be bent, or curved, to mate properly with the guitar's side.

No problem. Out comes the trusty bending iron. I cut a piece of mahogany a bit larger than needed for the final patch as tiny pieces are very difficult to bend. Even larger pieces need gloves as that iron gets hotter than the surface of the sun. Making sure to keep the mahogany damp, I gradually worked the wood until the heat and steam loosened the fibres—you can feel this happen. Then, working along its length, I bent the piece to the right curvature to match the guitar shoulder.

Instrument Repair - Acoustic guitar side fix
Instrument Repair - Acoustic guitar preamp

Once it was there, I clamped the bent wood in an acoustic mould (I picked a suitable position to mate with the bent wood) and waited for it to cool and dry. I could then cut it to shape and glue it in place.

20110625_DSC_0025_small

The sides of an acoustic—and in particular, this area—play a very small part in its overall tone. This is why it's possible to cut bloody, great holes for preamps in the first place. This patch is not going to have any effect on the guitar's sound. It will, however, allow the new preamp to be mounted and will get this guitar gigging again.