This is how to make an acoustic guitar series-part four-bracing the top. In this part of the series you will learn how to prepare your internal braces for the top, and how to glue them in place before carving. Here is everything you need to know. Enjoy.
Gluing the Braces to the Top
When you make the top of your acoustic guitar, after the plates have been joined and the rosette and soundhole have been addressed, it’s time to start working on the internal braces. This is where you strengthen the top, and give it a voice.
The guitar top by itself is not very strong. It’s a thin piece of wood, and it can really benefit from some extra support underneath. This is with the braces come in, and how you place them will effect the way the guitar sounds.
Bracing is actually a lot easier than it’s made out to be. In truth, if you just follow a bracing plan from a good book, and do it the way they tell you, it will create a good sounding guitar. Could it be better, sure. However, it could be a lot worse too.
In this part of the guitar build, I’ll show you exactly how to lay out the braces, and what order to glue them all down. The process is pretty easy to follow, and you can do the same thing on your guitar build.
The following directions don’t constitute a set of plans. Make sure that you’re using this as a guide, and following the dimensions that are outlined in your book. It’s important not to mix plans, because it can create problems down the line.
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I have made plenty of guitars according to the dimensions that were in the book I was following, and they all came out just fine. In the beginning, it’s more important to get the process right that it is to worry about any fine details.
If you Missed Last Week, Check out How to Make an Acoustic Guitar – Part Three
Deciding on a Bracing Strategy
In the beginning, one of the first things that you have to decide as your bracing strategy. It’s very common to do an x-brace pattern, which has been a standard that was established by the Martin guitar company a very long time ago.
This is a very effective bracing strategy because it’s borrows some of the good points of ladder bracing and some of the bad points are removed. It essentially capitalizes on the best parts, and removes the worst parts.
That being said, ladder bracing it isn’t bad, and it was used for a very long time before the x-bracing pattern was derived. If you are making a classical guitar, you’ll use a fan bracing pattern, so again make sure to follow your plans.
You can always lay some braces out on the actual guitar top while you are planning. This will help you do some visualization, and see what those braces look like under the top. Between your book, and the hands-on exercise, it can be a very good start.
Marking the Layout on the Top
Once you decide on a bracing pattern, it’s very helpful to mark out the brace locations on the exact top. Not only does is make gluing down the braces a lot easier, it also makes several other operations a lot easier as well.
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When you are in the middle of trying to glue down a brace, having those guidelines will relieve some stress and make it easier to know where it needs to go. The last thing you want to do is let the stress of gluing something down make you place it in correctly.
While it’s not the end of the world if this happens, especially if you catch it in time, it’s just a waste of time. Even if you’re glue does dry, all you have to do is chisel off the brace and start over. Again, not too difficult, but a waste of time.
You can always erase pencil marks, and spend the time you need to get this right before moving forward.
Lay everything out really well and then check it against your set of plans or your book. It’s at this point where you need to make sure everything is perfect, and it will also mean that you’ll have a lot less to think about as your gluing your braces down.
Make any changes that are necessary to the drawing, and proceed to the next step only when it’s perfect. Take your time, double check, and you can even use the exact braces to dry your lines, which will make it a lot easier.
Creating and Gluing the Bridge Patch
I recommend that the first piece you glue down be the bridge patch. This is a flat piece of wood that is designed to sit under the bridge, and it provides a place for the ball ends of the strings to rest.
The bridge patch also provides a way of mechanically locking the bridge and the soundboard and the strings together, and it gives the strings a little bit more to pull against. Typically this is made from a hardwood, like Ebony or Rosewood.
In this case I made it out of the same material as the top, mahogany. While not as strong as Rosewood, it’s still a pretty stout piece of wood, and it will do just fine as a bridge patch.
Since the bridge patch fits in between the X-brace legs and one of the lower face braces, it’s important that you designed it to fit exactly into your plans. If it’s too big or too small, it will affect the positioning of other braces.
Once you have the piece cut and shaped so that way it fits in between the braces, the next step is to sand the top and bottom edges to a taper.
Don’t taper the parts of the bridge patch that will sit against the braces themselves. Only taper the two straight edges that do not touch braces. This is an easy process, just do it with some sandpaper on a block.
Before you glue down the bridge patch, use the block to taper the top and bottom edges and that will help to make a smooth transition to the top. Taper them in about a quarter inch, but don’t go much farther than that.
Milling and Notching the X-Brace
A lap joint is a very common jointed woodworking, but on the x-brace is a tiny bit different than normal. Most lap joints are square, but since the x-brace is not a cross, but an X, those notches actually have to be angled slightly.
The easiest way to do this is to set up the two braces in the shape of the X, and lay them against your template or the back of the soundboard to make sure that the spread is correct. Then, Mark where the notches need to be and where the braces cross each other.
These marks will show you where to remove material and it will also show you the angles. All you need to do now is saw down through those marks, and clear out the material in the middle, not going more than halfway deep.
Do this on both sides of the x-brace, and bring them back together to test the fit and make sure it’s coming together well. You don’t want to dig to deeply, otherwise there will be a gap in between the two pieces of wood.
You also don’t want to go to shallow, otherwise the one leg of the brace won’t be able to go down all the way flush against the soundboard. Keep on checking your joint, and keep on removing material until both pieces can go flat and flush.
Pay very good attention to that angle. You definitely don’t want to cut straight through. If you do, you’ll end up with a really wide gap in between the legs of the x-brace, and that is going to directly affect how sound transmits through those bars.
Take your time. This is a very important part of the build, don’t confuse that with being a difficult part of the build, because it’s not. It’s just important, and if you have patience and do the right thing, you will end up with a very functional x-brace joint.
Laying out the Finger Braces
This is why it’s a good idea to do them first, because you can lay out the x-brace to find the notches.
Even though wood glue is very strong, if you can provide a mechanical way of holding down your braces then you have double coverage. Once the finger braces are glued down, the legs of the x-brace go over them, and hold them down as well. This is two layers of protection against the braces falling off.
In order to hold him down, you need to make a small notches into the end of the brace, where are the finger brace goes underneath. These are really small, and gluing down the finger braces first allows you to make those measurements.
Another thing that you can do when you glue down your finger braces first as you can shape them slightly. This makes the carving process a lot easier, and the results are the same as if you were to carve those braces with a chisel.
Leave enough that you can glue the brace down obviously, but remove as much as you can.
Working like this is actually really good, because it reduces the amount of time that you’re going to have to spend with a chisel later. This can be good for new woodworkers and guitar makers because sometimes the chisel can be intimidating.
Don’t think that you’re not a guitar maker because you aren’t using the chisel on your braces. Many manufacturing companies that produce guitars use braces that are entirely pre-shaped before they are glued to the soundboard.
This is completely normal, and they make millions of guitars just like this. When you add a little bit of that production style work to your own process, he can help you alleviate some of the work and end up with the same results either way.
Gluing Down the Soundhole Braces
After working on the finger braces, you can work on the sound hole braces. These have to fit in between the upper face brace and the upper legs of the x-brace. Just like a bridge patch, the fit needs to be good.
Cut out a couple of these, which are a mirror match of each other. Lay them down on your template that’s written on the guitar top, and make sure they fit perfectly. Sand the ends as needed, and taper the two edges that don’t touch braces.
The purpose of these is to provide a little stiffening action around the sound hole. As the guitar plays, vibrations transmit through the wood on the top and through the braces. The sound hole doesn’t have any material at all, so vibrations are lost in this area.
For this reason many more, they are an important part of your bracing system.
Make these out of the same material that you make the rest of your braces. They can be anywhere from an eighth of an inch to a quarter inch thick, just sand them down or shape them to be tapered on the sides.
These braces are another good candidate for a little bit of pre-shipping. The belt sander does a really good job of tapering the edges, and in a few seconds on each side you can do what might take several minutes with the sanding block.
Gluing the Upper Face Brace
Follow your plans or your book, and use the arching measurements that they recommend.
You can also go flat. There of been many great guitars that have flat tops, without any type of arching or doming at all. While sometimes they can look a little concave in the right light, the performance is still typically very good.
After arching the back of the upper face brace, you have to clamp it to the top with deep reaching cam clams. This is important, because you need to not prevent the top from curving to match the profile of the brace.
The top is more flexible, so it needs to move to the shape of the brace, not vice versa.
Clamping in a pinching type of arrangement is the best way to allow this bending to occur but still provide clamping pressure. Use several cam clams to spread out the pressure, and press the brace and top together.
When the glue dries, the top will be bent slightly to match the curve that you created on the bottom of the brace. This is good, and exactly what you need to do when you make a top that has a slight dome.
Gluing the X-Brace
Again follow your plan or your book for the actual size.
Since this is a little bit on the larger side, it’s a good idea to prepare all of your clamps and do a quick dry run before you add any glue. It’s better to figure out your problems now before they’re covered in glue, and you possibly run out of clamps right in the middle.
Get your strategy down, and get the placement of your clamps down in order to minimize any shifting or any sliding. You also don’t want to get glue all over the bottom of the sound board because the legs moved around into places that they shouldn’t have.
Once you have your pieces down, apply then layer of glue to the bottom end of the x-brace, and lay it down carefully right where it needs to go. Use some clams on the ends right away, and press the tips of each brace down to the board.
These four clamps will set the shape of the x-brace, and prevent it from wandering around while you are installing all the other clamps. Go through the sound hole and clamp the center in position next, and then start applying the rest of the clamps.
These two pieces of wood need to have a strong joint, because they’re going to live together for a long time.
On top of that, they’re going to vibrate together for a very long time. This makes the joint between the two even more important, because any area that’s been compromised will be slowly rattled away as the guitar plays throughout its life.
Don’t underestimate the power of vibration. Vibration over long periods of time can test the strength of any joint. It can also exploit a weakness in any joint, and eventually cause the joint to fail.
Make sure you have a nice even layer of glue, and apply your clamps quickly and effectively with medium pressure throughout. Double check your joint after you’re done, and add more clams were necessary.
Wipe away any glue residue too, not only will this make the cleanup process a lot easier later on, but I can also expose areas where the joint isn’t quite as tight as you thought it might be. If you find something like that, make sure to address it before moving on.
See Also: You Can Make an Acoustic Guitar
Gluing the Lower Face Braces
The lower face braces have a large influence on the tone of the instrument mainly because they affect how loose the top will be. This is pretty simple to manipulate, and you can see how the structure changes right away.
These braces go on an angle from the leg of the x-brace and they cross the center line of the guitar top. If you angle of these so that way they are more perpendicular to the center line, they will have less of a bracing affect.
If you angle them closer to parallel to the center line, they will have a much greater stiffening affect. Essentially you can use this to your advantage, because a top that is a little weaker can benefit from having lower face braces that are a little straighter.
You can also do the opposite and make the top a lot more open. Simply angle your braces so that way they’re a bit more perpendicular, and it will loosen up the bottom end of the belly of the guitar and allow it more flexibility.
As you make more and more guitars, you will end up experimenting and playing with these little differences.
Gluing the lower face braces down is pretty similar to gluing the others. Apply a thin layer of glue but an even layer of glue to the bottom of the brace, and then clamp the two ends down exactly where it needs to go.
Before you do that, if you are notching the ends underneath the leg of the x-brace, make sure to plan your notches of course, so you have room for it to fit. You can use the notch as your first clamp, and then use another on the end of the brace to hold it steady.
Just like the rest, make sure you use even clamping pressure. It’s not about clamping the heck out of the brace. It’s about even pressure that holds the two pieces together while the glue dries. That’s how you create a strong bond between your braces in your soundboard.
Apply several clamps along the length of the brace, spacing them tightly. Don’t worry about using too many clamps, because there is no such thing.
The Completed Soundboard
Besides, there are going to be way too many clamps in the way to do it right.
There are systems out there that let you glue everything at once, and the most common is a vacuum press. If you’re really interested in speeding up this process, you can invest in a vacuum press and all you would need to do is place your braces and then lock the press.
However, for most guitar makers the common method for securing the braces is glue and cam clamps. Make sure you have enough of them, and working in stages will help. This way, you get some of your clamps back when you go to the next step.
Once everything is glued down, it’s important to inspect the joints. Take some time and make sure that you see good contact between all the pieces and the soundboard. This is a little extra step that can ensure lifetime of good guitar playing.
At this phase you can also chisel away some of the excess glue that may not of been cleaned up well enough while it was wet. This will also reveal any gaps or issues that need to be corrected before moving forward.
If you find anything that needs to be addressed, take care of it. Even if that means carving off an entire brace and sanding your way back down to the soundboard, then do it. It’s much better to handle this now than to handle it 20 years down the road.
The big advantage here is you have access to the inside of the guitar. If you have a brace that rattles loose in the future, you’re going to have to replace it by shoving your arm to the sound hole of the guitar, and it can be very difficult.
Take care of everything now, and you’ll be happy in the future.
See Also: Acoustic Guitar Making For Beginners
Bracing the Top Wrap-Up
While you can spend a lot of time learning all of the nuances of internal bracing, you can also get started right away with a lot less.
Like most things, the high-end of any skill is very subtle, and takes a long time to fully appreciate. However, don’t let someone in a different part of the journey make you think that you can’t start your own journey.
Many times this is not the fault of anybody but you. If you allow yourself to think that all of the things that they are working on is something that will make or break your guitar right now, then you are creating a monster out of nothing.
People at the high-end are working on different things and trying to improve different things than you are as a beginner. Don’t worry about those things, because over time and through making many guitars you will eventually have plenty of time to worry about them.
Now is not a time. Follow a good bracing plan in either a book or a set of plans, and it will make a very good guitar. That bracing plan is a down the middle approach that will ensure your instrument sounds good.
See Also: Practical Acoustic Guitar Making Advice
Coming up Next Week
Next week, I’ll show you how to carve the braces. After the braces are installed, it’s time to bring out the chisel and do some carving. This is a lot more fun than it sounds, and with a sharp chisel it can be pretty easy to.
The biggest take away here is that you need to you have a sharp chisel. This means if you’re following along at home, and you don’t have a sharp chisel or a way to sharpen the chisels that you already own, you need to fix that before next week.
Buy a good combination water stone, like something with 800 on one side and around 4000 on the other, and you will be in good shape. Watch a couple YouTube videos on how to sharpen, and have some patience with your chisel in the beginning.
In a couple hours you can learn enough that you can take an average chisel and turn it into a light saber of sorts. It’s a lot easier than it sounds, and if you go slowly the process will be a whole lot easier.
With that chisel I’ll show you how to carve the braces, and also explain why they are carved in a certain shape. Also, I’ll show you how removing material from certain places affects the tone, and how to remove the most mass without compromising on structure.
This is really a fun part of making the guitar. This is where you get to create the voice, and you get to control how the top is going to work. Join me next week, and you’ll see exactly what I mean.
If you have any questions, please Post a Question in the Q&A Forum and I’ll be glad to help. Happy building.
Next Post: How to Make an Acoustic Guitar Part Five
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