The beauty of a guitar like this is that you can usually pick it up for a fraction of the retail price, repair it and have less in the finished guitar than if you had purchased a lesser guitar.
And most often it will be a much better guitar because you will have not only repaired it but it set it up to suit you as you built it. My initial budget will be $100.00 and I should be able to stick pretty tightly to it, after all I am not going to be adding any hi-tech pieces, I’m pretty much sticking to low tech tried and true off the shelf stuff as I said. The repairs are labor intensive; doing them myself I will make this guitar affordable.
I say neck repairs, because we are going to repair this neck in two steps. First we will address the break and repair that, then we will address the stability issues due to the break and take care of those.
The first thing to do is get the tools, glues and clamps you will use together. I like to have everything I need right there as I do the repair. No leaving to search out this clamp or that block of wood. In this case, clamps to hold the repair, Aliphatic Resin wood glue for the initial repairs, soft cloth to protect the neck surface and fret board from the clamp jaws. A damp cloth to remove excess glue and a few small blocks of wood to keep things aligned correctly during the clamping process.
I have found that for me the best thing to do is read through the repair information, or plan it out in your head, get your materials and then go step by step through the repair.
It always works out well for me that way. I rarely get to do that anymore, because I am usually working on something I myself have planned out, but the few times I find myself working from someone’s designs I do it by doing a complete read through, gathering the materials and then doing the job step by step from the directions.
Aliphatic Resin Glue: I have seen a few posts with pros and cons concerning PVA, common white glues, and Aliphatic Resins, yellow carpenters glue, and even Hide glues. For me the bond is better with Aliphatic Resin Glue. It is specially formulated to work with Porous material. It tacks faster and cleans up easily. It is also completely non toxic: When I learned several years ago Aliphatic resin was the choice of my teacher. I have seen posts calling Aliphatic Resin a relative newcomer, but it has been around and been used since the sixties.
PVA has also been around for a very long time. It is not water resistant. The strength and creep resistance are not very strong. It is not a good gap filler. It sands poorly and it does not accept stains well.
Hide Glue: Hide glue was the choice of instrument makers for centuries. It is very strong, transparent at the repair, water resistant, good bond properties with wood, even oily woods. It is a good gap filler. Cleans up with water. This glue is still used by many Luthiers. It has its draw backs, it should be kept in a powdered form and mixed as needed: If I were doing a repair on an older instrument I would have used this glue to stay period correct.
Aliphatic Resin Glue: Aliphatic resin glue is water resistant. It can fill and adhere well in small gaps. It is sandable, and very often I will use a small amount of Aliphatic resin and some sawdust to form an on the go wood filler. It has good shock resistance value. The color is near transparent after drying. Applying a uniform thin coating over two surfaces is usually sufficient to enable a good bond with or without clamps depending on what you are trying to achieve. You can usually handle the piece with twenty minutes or so, but leave it to cure a full twenty-four hours before getting serious about working with it.
Use good clamp pressure, but watch that you don’t squeeze too much of the glue out. That is the same with any glue. The best application is with a brush so that there is a uniform coating on both surfaces. You can buy glue bottles very cheaply that include a brush for that purpose. Rub, or push the pieces together, clamp if necessary and leave to set up.
When I say clamp if necessary, what I mean is if there are pieces that require no clamping simply because they have no forces working against or on them. A neck repair, or a bridge repair would need to be clamped however because there will be forces acting against those surfaces. Light clamping will suffice and when you remove the clamps after 24 hours you will find you have a strong, permanent bond.
Here I am looking the break over, test fitting the pieces, seeing exactly how bad the break is and making sure I am aware of where I need to make sure the glue gets to. In the second photo you can see that I need to make sure the glue gets deep into the fracture. I will use some pressure from my hands to ensure the spreading of the break so I can be sure the glue works its way all the way down into the separation between the neck and the fret board
Clamping in two places on the flat and then running another clamp across the top to keep the pressure on the horizontal plane so that the neck position is correct as it dries. Notice I have placed the flat clamps (Down force) first and then used the foot of the first clamp as a base to bring the head-stock in and level. I have used a soft cloth as a pad to protect the neck in front of and in back of the break.
This break went together very nicely and really only required downward pressure, but I need that over a wider area without using two clamps, as there was room at the break for only one clamp, or down force area. I used a block of wood to keep the pressure even and spread it across the surface.
There is not much to guess at in this part of the repair. Look at the breaks, look at the ends. They will usually fit together snugly. Whatever way they push together remember to use very little force when fitting them so that you do not break more wood from the joint and cause the break to come together too loosely. The snug fit is usually where the pieces belong.
I apply slight outward pressure to see how the pieces will fit back together. When I glued the joints I used pressure from my hands to open the break enough to squeeze glue into it:
The force of the wood, once I release the break, on the broken area will force the glue down into the break. I opened the break and squeezed plenty of glue into the broken area two or three times to make sure that as the wood came back together the glue was forced down into the break and not simply back out.
I use the Aliphatic Resin here because even a slow drying Cyanoacrylate (Instant Glue) will probably dry faster than I want it to. I also want a semi flexible bond here.
Do not misunderstand, I am not looking for flex that you or I would normally notice, I am looking for something closer to the natural flex this neck wood would have without the break. Aliphatic Resin provides that better, in my opinion, than Cyanoacrylate can. That flex should allow the joint to last for the life of the guitar without issues of any kind: Glue, clamp, set aside for 24 hours and then come back to your project.
The thing you should notice here is that the joint has set, and the reflection of the shop lights on the near surface of the neck form a perfect arc despite the fact that the neck was repaired in that area.
You can see stress fractures in the clear coat from the break in the upper picture. You can also see how well the break has been reset. When I set this break, any break, I make sure my sides are lined up correctly, again I will stress, that I make sure to tread lightly fitting the pieces back together so I don’t end up with a bad set. If you are careful the pieces are right back where they were, side by side, interleaved in some cases, and you will have a stronger joint because of that.
NECK REPAIR PART TWO
Once your initial repair has cured for 24 hours then do your splices on the back of the neck. These are not difficult splices to make. Here I have routed 1/8” wide slots into the back of the neck. You can see I have done nothing else with this neck at this point, except to cut the slots and glue in the Luan strips.
I could have used Biscuits that are made for joinery, but that would have left an area to cut off in any case, so it is easier to simply cut pieces from Luan scraps and use them. This is simply reinforcing the area repair so that when there is forward flex because of string tension the neck will not deform. It isn’t a large repair area, it is not a particularity deep repair, it is relatively small but it adds significant strength to this repair to ensure it remains stable.
I used a hand held zip type router, but any small hobby sized router will do. I like the zip type router because it is so small and lightweight, and I have used it so often that I am comfortable using it by hand without a guide. I made a very low pass, I call it ‘Scratching the surface,’ to set my line. The second pass is deeper and stays straight because I made the first cut very light, yet it scored the wood and the bit follows that scoring in a straight line.
If you are not comfortable using a
router free hand then take the guard and run it down to the edge of the neck.
That will keep you in a straight line relative to the neck.
Lay the neck on a flat surface and clamp it to hold it securely. Using the stock guide or building one from a piece of metal, run it down along the edge of the neck as shown in the illustration to help guide the router in your hand. This will make one side solid for you and serve as a relatively straight guide to cut the groove. You are going to cut a 4” long groove with the router. Cut it very lightly into the surface. I would suggest no more than 1/16 of an inch. This will stabilize your following passes as you deepen the splice. Remember to stay to the outside of the neck, away from the center section that houses the truss rod.
I do these two repairs separately because it is too much to juggle at one time. I prefer to do the initial neck repair and then cut my slots to introduce the Luan splines.
The success of both these repairs hinge on making sure that you are setting the initial break correctly. This involves looking the break over, checking it for wood loss. Dry clamp the pieces to see how they will compress, how the pieces will fit.
When you do clamp the pieces make sure to use protection on the clamp jaws: Also make sure you do not over tighten the area. Too much pressure can damage the wood. It can also force too much glue from the repair areas where it is needed.
Finish: Sand down the repaired area and prime it. You can use a good quality filler to take care of minor imperfections and or nicks and scratches. Sand, re-prime, bring it to a primer/sealer coat with no noticeable pinholes or imperfections and leave it.
For this Fender Acoustic I sanded the repaired area, used a small amount of filler to take care of imperfections, rounded the top of the headstock over and sprayed the headstock with a sandable gray primer/sealer, sanded it back, re-primed and moved on to the next repair.
I use basic sandable lacquer primer/sealers. Gray, white, black, red, it dries fast and the colors can bring me back to a closer match to a painted surface fairly quickly. If I am working with wood I can use a clear lacquer primer, or sealer to achieve the same ends, sealing the wood and the area.
The break areas were sanded with 220 grit wet or dry sandpaper and then primed or sealed. They were then sanded with 320, 400 and then 1000 grit and re-primed: If there are problem areas I will find them then. Pinholes, scratches that escaped my eye, an additional coat of primer or a small amount of lacquer spot putty will fix the larger pin holes or scratches. Sand that to 1000 grit and then re-prime it. Although I use wet or dry sandpaper I do not use it wet on bare wood. I prefer it for its anti clogging properties.
This illustrates the neck repair for you and should give you the knowledge that you need to do your own neck repairs. The repairs I do are pretty straight forward, no rocket science. You can find repair shops that will throw in three pounds of rocket science and end up in the same place. I use straight forward carpentry skills, take my time, and use common sense on the repairs. I also use common tools. No gauges, no $600.00 setup to true the neck. Luthiers and wood working enthusiasts were doing the same work long before those tools came along. Do you know what we call those instruments they built without all the fancy equipment? Masterpieces.
So, take your time and go step by step. If you are unsure of your glue techniques, take something simple and glue it up. A few blocks of old wood, a simple broken table leg. Nothing great, just something you can practice on. Then sand it, seal and prime it, and bring it to a point where you can see it only needs light sanding and paint.
Do this more than once if you need to. It will cost you next to nothing, and no one learns entirely via a book, or even watching, sometimes hands on makes the written word come to life in a way it could not otherwise come to life. While I tend to stay away from modern tools and expensive setups, I am not anti technology. It is much easier to consistently reproduce a certain soundboard characteristic through precision measurements and digital calipers, gauges, etc. Or arrive at duplicate neck setups through the use of precision gauges and digital machinery to do the work for you. But to me, for me, I like to feel what I am doing. I think if you do something often enough you can get the same repeatable results, and I am not building instruments for the masses, just myself and a few others.
Below is the finished repair, sanded and primed, and re-sanded and primed once more until all the imperfections have been sealed or removed. From there I will move on to the rest of the guitar work, leaving this in primer, ready for final finish, once the rest of the guitar is bought to the same point.
And last but not least, the idea of these projects is to do builds that the average man can get tips from, learn from and do their own builds from that do not break the budget. I’ll be back next week with more on this build…
PcGeos (Geo Dell): https://www.pcgeos.com