Solid or hollow? (Note that I got this from a book that I bought so It does not have any pictures. But this plan works awsome!!)
The first thing you should make up for yourself if you want to build a guitar, is whether you want a solid-body guitar or a semi-acoustic one. If it's your first guitar: don't even think about semi-acoustic. Even after my two solid guitars, I would hesitate to try a hollow one. The reason for this, is that a solid guitar is much less critical to build: the shape doesn't matter. The sound of a solid guitar is mostly determined by the electronics (pick-ups, filters). A hollow guitar on the other hand, will sound poor or resonate like hell if it's shape isn't right. This requires experience and expertise. You should follow some lessons or read specialised literature about this subject before attempting a semi-acoustic guitar.
The wood
The most expensive solid-body electric guitars are made from mahogany. This, however, doesn't necessarily mean that this is the only ultimate guitar material. The choice of material will determine the sound quality in a certain way, but for a solid-body electric guitar, the influence of the material on the sound is not huge, but it's noticeable. The two important rules are: the harder the material, the clearer the sound (a softer material absorbs more high frequencies); and the heavier the material, the longer the sustain (i.e. the time a string keeps on vibrating).
Notice that I say 'material', because there is no reason why you couldn't use something else than wood. You could make a transparent guitar from a huge chunk of plexiglass, which would be an excellent material due to its hardness. You could even use aluminium.
My both guitars are made from multiplex — mostly due to the fact that it was lying around when I wanted to make my guitars. Multiplex is laminated like plywood, but with more and thinner layers (each layer is about 1.5mm thick). The layers alternate between a hard and soft type of wood. It's quite heavy, so good for sustain, but due to the soft wood layers, it dampens the higher frequencies a bit. The major advantage is that it's of consistent quality due to its laminated structure. The layers also make it easy to manipulate. The big disadvantage, however, is that it absorbs paint like hell, making it very hard to cover the guitar with a smooth layer of paint or lacquer. Moreover, it's hard to create smooth curved surfaces because of the alternating hard and soft wood. And because the soft layers absorb the paint/varnish much more than the hard layers, painting such surfaces (especially the sides) is a real pain.
So to make a long story short, I would never again use multiplex for a guitar, unless I would really need a heavy guitar with a fat, warm sound, and I would find a foolproof way to paint the damn stuff. I don't really say you shouldn't use it. It's a pretty nice material to make your first guitar or a prototype, but be aware of its limitations.
If you go for a solid chunk of wood from a tree like mahogany, beware that it may have weaker parts or defects in some places. If you want to use such a piece of wood, you must be very careful in choosing it. It may be a better idea to either buy this wood in laminated form (i.e. several thinner layers of the wood are glued together, with each layer perpendicular to the previous), or laminate it yourself.
Somebody asked me whether MDF would be a good material. MDF is a synthetic type of wood, created by compressing very fine wood fibers at an extremely high pressure. It's commonly used for high-end speaker cabinets. He was concerned if it wouldn't influence the sustain in a negative way. This was my answer:
I still haven't had the time to make a new guitar, so I haven't tried MDF yet, except for some speaker boxes I made. But I am quite sure it is a good material, since some guitar manufacturers used it for their models. It is very dense and consistent in quality, so it should be perfect for making a solid guitar.
Considering the sustain: instead of a loss of sustain, MDF will most likely contribute to a gain of sustain, just because of its high density. You may assume that the denser the material used in the guitar, the longer the sustain. Some people say that the ideal electric guitar should be made of concrete, but you understand it would be quite unhandy hanging a 20Kg block of stone around your neck!
So MDF would be a really interesting material to try. You can get it in a wood store. It's not cheap, though surely a lot cheaper than mahogany. I don't think MDF is easy to get in plates as thick as a regular guitar, so you may need to use two plates and glue them together. If you use strong glue for this (specialized wood glue) and apply the required pressure as described in the glue's directions for use, the whole will be at least as solid as one big piece of wood. You can use screws to tighten the plates against each other while the glue dries, and remove the screws afterwards and fill the holes. When using two plates, you also have the additional advantage that it will be easy to incorporate hollow parts in your guitar, or cut holes through it, since you can work on the two parts separately first. (This was also the way I worked with the multiplex.)
Mark has actually built a guitar from MDF, and mailed me his experiences. A summary: 1. Cutting special shapes out of MDF is not so easy due to its high density. Make sure to use suitable tools, and take care not to overheat them. 2. It's heavy! Either keep the body small/thin, provide enough holes, or hollow out large parts. 3. Painting it is easy thanks to its hardness. 4. Despite its density, sustain is only similar to mahogany, probably due to its dampening abilities.
Hollow-body or semi-acoustic guitars are a different story. The two guitars I made, were solid, so I can't tell you much about the others. As far as I know, acoustic guitars, hence semi-acoustic ones too, are often made from fir-wood or maple. The best thing you can do if you plan to build a semi-acoustic guitar, is asking advice of someone who is specialized in wood for musical instruments. At any rate, it is again recommended not to use one single piece, but laminated wood, i.e. several layers glued onto each other, to get a more consistent quality. The largest problem with semi-acoustic guitars is resonance, for the wood mass is small, hence picks up vibrations easily. Therefore a good design is essential.
The pickguard or cover plate (which will contain the switches) is mostly from plastic in commercial guitars. However, you can also use thin wood, or even metal, for it (iron wouldn't be a good idea, however, because it may interfere with the pick-ups). Or you can just omit it, and run the switches and potmeters through the guitar body itself. This requires accurate milling of the wood so that only a thin layer at the top remains, so don't try it if you lack the experience. I used a kind of compressed wood board for the pick guard of my first guitar, and painted it with spray can paint. The result is very nice and actually looks like real plastic, but it's a bit less resistant to scratches than plastic, of course.
The design
Once you have an idea of how you want your guitar to look like, you need to transform this idea into a usable "plan" of your guitar. It is very helpful to use a vector drawing program, like Canvas or CorelDraw on a computer for this. You then can draw the shape in actual size, and zoom in and out for details or an overview respectively. A great advantage is that you can easily tweak the shape without having to rub out and redraw things. You can also easily align the components this way, for it is crucial that the pick-ups line up with the strings, which must line up with the neck by correctly placing the bridge. You actually can "draw" the strings in your drawing program, and correct easily. Of course your guitar won't fit on a single page. You'll need at least four pages for the body alone. However, it is recommended to add the neck to your design too, even if you're not going to make it yourself. This will allow you to determine the correct position of the neck (see next section).
Your "plan" should contain almost every part of your guitar: body shape, pick guard, components like pick-ups, switches, potmeters, cable connector (jack), and bridge. In other words, you should have a complete "paper" guitar. This requires accurate drawing of the components, especially the pick-ups and the bridge, so that you can align them correctly.
You should try to make the whole "balanced", i.e. the mass should be evenly distributed. Otherwise it may be unhandy to play it. Of course this is hard to determine beforehand, for you must also take the weight of the electronics into account. A bit of guessing is necessary, but you can also provide hollow spaces in the guitar which can be filled to compensate for weight. Also try to make the guitar not too heavy: although a heavy guitar might have a better sustain, it could be a torture to hang it around your neck! Again, you can use hollow spaces (preferably at the sides) to make it lighter.
Once the "plan" is ready, print it, without the neck. Since most of you won't have an A2 printer, it will consist of several pages which you'll need to glue together. Again, do this accurately! You can draw some additional lines onto the page borders before printing to improve accuracy (see image at the right). What you then have, is a complete "paper guitar". If you plan to make the pick guard yourself too, make a separate print-out of it.
Now you can easily transfer your paper guitar plan onto the wood: just lay it on top and use a marker to draw the shape. Cut away all parts in the paper which should be in a hole in the wood, and draw these holes too. The same with drill holes. (Imagine you'd have to determine all those positions by measuring only!) It can, of course, be easier to just lay the component itself onto your block of wood, and then mark its position and the position of the drill holes. This is something you'll have to see for yourself, as there are no general rules.
Please do not mail me asking to send the designs of my guitars. Be original, make your own. They are in a format few people can use anyway. I won't respond to any mails asking for a sketch of my guitar or any other model.
The neck
The neck is without any doubt the most crucial part of the guitar. If your neck has not the right shape, it may be hard to play it. If it's too thin, it will bend too much, or even break, under the tension of the strings. Necks are often made of maple wood, which exists in various qualities. More expensive necks can be made of ebony or other rare wood types.
There are two construction methods for necks: the first one features a neck which runs from the top all the way down to the body. In other words, the neck is a part of the body of the guitar. This construction is used in a lot of commercial guitars. It has the advantage that it's completely solid, hence no absorption of vibrations by loose connections. The disadvantage is that once the neck is damaged beyond repair, the entire guitar is ripe for the scrapyard. Also, the properties of the wood are more crucial as you need a longer piece of consistent quality.
The second construction is a separate neck, which is connected to the body by glue or screws. Acoustic guitars have a glued neck, mostly with a dovetail connection. Lots of electric guitars, like Fender's Tele- and Stratocaster, have a screw connection. Tbis means that the neck can be easily replaced, or disconnected for repairing. Another great advantage is that the angle of the neck can be made adjustable, as is the case with the Stratocaster. A disadvantage is that if the connection is not tight enough, you will lose sustain. I used an adjustable system on my first guitar, as shown in the image on the right, and it works well. The rightmost screw pushes the neck upward, while the other large screw pulls the neck towards the body, ensuring a fixed position. The leftmost screws (2 or preferably 3) serve as the canting point. If you only use normal screws to fix the neck, you can still adjust its height or angle by placing metal or wood strips underneath it.
Someone once mailed me to ask whether to buy or make the neck himself. This was my answer:
It's very hard to make a neck, because:
1. there must be a special rod, called a "truss rod", built into it to compensate for the tension of the strings. If you make a neck without it, it will bend too much and the guitar will be impossible to play. However, such rods are sold almost nowhere separately. I made the neck for my first guitar myself, but it's quite thick because it doesn't have such a rod, and this makes the guitar less pleasant to play. And the piece of wood you use for it must be of perfect quality, which is not evident.
2. you'll need to install all the frets yourself and this is a horrendous work which involves some mathematical calculations and very precise work. And, if you do something wrong, you have to start all over, that is: with a new neck.
In other words: I strongly recommend to buy a neck, like I did for my second guitar (it was a second-hand neck, but in great shape). If you're really good at woodworks you can try it yourself, but it's likely you'll have to go through a few prototypes to arrive at a decent neck.
If you should want to try it, or just if it may come in handy: this is the formula which can be used to determine the correct distances of the frets, where l0 is the length of the strings (see image), mostly around 65cm (25.5"), and x = 0 (nut), 1, 2, ... up to 21 or 22:
l(x) = l0 - (l0 / 2x/12)
Example: if the strings are 65cm:
l(0) = 65 - 65/20 = 0cm (the nut),
l(1) = 65 - 65/21/12 = 3.65cm,
l(2) = 65 - 65/22/12 = 7.09cm,
... and so on.
If you use an existing neck, there is only one thing you must take care of: the middle fret (with the two dots right above it) must be in the middle of the strings. This determines the correct position of the bridge.
The fretboard
If you are making a new neck, or if you want to replace the fretboard on an existing neck, here are some considerations.
Typically, ebony, maple or rosewood are used for a fretboard. But any other material that is hard and dense could do. It doesn't even need to be wood, you could try some kind of hard plastic if you really want to try something special. Don't use soft materials because they will wear out quickly. Don't use light (non-dense) materials either, because they will reduce the sound quality. Also, avoid painting or varnishing the fretboard. I made this mistake on my first guitar and although the varnish still holds, it will eventually wear out and make the fretboard look ugly.
For the frets, you should use special fret-wire. This is a T-shaped wire, with little hooks at the bottom of the leg of the 'T', to make the wire clutch into the wood. To make sure the wire fits well, you should pre-bend it to approximately the same curve as the fretboard. A little glue is recommended to make sure the frets are seated properly. Thermal glue, or some other glue which can melt, would be a good idea. This allows to easily replace worn out frets later on, by heating them.
The bridge
Bridges come in all kinds of flavours and types, from the most simple type which is a metal plate screwed onto the body, up to the sophisticated Floyd-Rose bridge & nut combination which is designed to prevent detuning while using a tremolo bar. Most bridges also allow to adjust their height, which determines the so-called 'action' of the strings.
Despite the fact that it's written right above this paragraph, people keep on mailing me where to position the bridge. I'll repeat: the bridge should be positioned such that the half of the strings coincides with the middle fret. Actually there is a complication due to something called 'intonation'. Due to the fact that the strings are raised, pushing them down will increase their tone slightly. To compensate for this, the length of the strings has to be increased slightly. This effect is more pronounced for larger string gauges. This is why acoustic guitar bridges are positioned slanted, making the thicker strings longer than the thinner. Electric guitar bridges allow more fine-tuning by having adjustable saddles for each individual string or pair of strings. To determine the correct position for the bridge, extend these saddles almost to their maximum (i.e. loosen the screws), and then align using the saddles as reference.
Setting the intonation right for each string comes down to adjusting the saddles so that the first flageolet (played by holding a finger in the middle of the string while picking it) has exactly the same pitch as when the string is pushed down onto the middle fret.
The electronics
Pick-ups
The most important electronic part of an electric guitar, are the pick-ups. These convert the mechanical vibrations of the strings into electric pulses which are sent to your amplifier. The very very first version of my prototype (see above) used a microphone for this, which caused more noise than tones to reach the amplifier. That's why pick-ups are based on magnetic fields, and strings are made of iron and nickel so that they can influence this magnetic field. The core of a pick-up is a magnet or several magnets, with a copperwire coil wound around it/them. There are two basic types of pick-ups:
Single-coil pickups (like those on a Stratocaster) consist of one row of magnets with one coil around them. The higher and thinner the coil is, the clearer the sound. This means: a pickup which looks like this in side view: will sound very clear, but won't have a high output. On the contrary, a pickup which looks like this: will have a warm sound with few trebles.
The same thing counts for humbuckers. Humbuckers (like those on a Les Paul or Gibson SG) consist of two single-coil pickups next to each other. They sound in general less clear than single-coils, but they have a much higher output. The most important feature of humbuckers is that, thanks to their special construction, they don't pick up interference from magnetic fields like single-coils do. Humbuckers also have the advantage that they can be used in several different coil combinations, just by throwing a switch. This allows you to choose between a heavy sound or a clear sound with only one pickup, for example.
As for making pick-ups: don't even think about it if you don't have steel nerves. I made two pick-ups, a single-coil and a humbucker. Both were rather experimental, and the single-coil didn't produce enough output, so I took it apart to make the humbucker. It was constructed from a few magnets from a cupboard lock, and wire from a damaged pickup. It works and sounds good, but I don't recommend trying this yourself if you're not too patient! It requires basic knowledge of magnetics, and it takes a lot of time and care to wind that hair-thin wire around those magnets. I used a "Technic Lego" construction for this, but it still wasn't easy. The risk that the wire breaks is very big. It almost made me mad at some moments!
In other words: it may be a much better idea to buy the pick-ups. There are lots of custom models available today. Mind that of the same type of pick-up, you often can buy specialized versions for neck and bridge positions. For the brands, I can recommend Schaller, which has good pickups. I bought two Schaller pick-ups, a single-coil for about $40 and a humbucker for about $50. Schaller does not seem to have a website, but there is a good unofficial site at http://besides.ipc.ru/schaller/. Other good brands are: Mighty Mite, Bill Lawrence, Seymour Duncan and DiMarzio. You could also order genuine Fender or Gibson pickups, but get ready to empty your wallets when you do.
If you want to know more about pickups, check out this page too: http://www.cybozone.com/luthier/instruments/pickups.html (if it still exists). The guy who made it seems to have quite some experience with them, so mailing him looks like a good idea if you want to know more.
Circuitry
Once you have the pick-ups, you need to provide some circuitry to select, mix and/or filter the signals, and send them to the output jack. There are two sorts of circuits: active and passive. Passive circuits are most common and do not require external power (batteries). Active circuits do, but offer more possibilities and an amplifier-independent sound quality.
The information on passive circuits in "The Guitar" is pretty extensive, but it tells not too much about active circuits. However, if you haven't worked with any electronics at all yet, it's better to start with passive circuits and eventually upgrade to active circuits when you're more experienced.
A precaution: don't feel tempted to implement all possible circuitry in your guitar. If you'd make the entire circuit described in "The Guitar", you won't be able to play through the jungle of switches and knobs! However, it's hard to tell what circuits will have a profound effect on the sound. The best thing you can do, is experiment, e.g. with a separate board with all possible circuitry on it outside your guitar, before you decide for the final circuit.
Most active guitar circuits are based on a single preamplifier which offers different sound 'flavours'. Koch is well known for its preamps. If you know enough about operational amplifiers (opamps), you can create your own preamp. The most important thing you must take into account, is that the preamplifier must be able to deal with a high imput impedance, for most pick-ups have an impedance around 8 kOhm!
Of course you need to be able to handle a soldering iron, so if you haven't touched one in your life yet, make sure to practice a lot before starting with the real thing, or you'll end up with a guitar that crackles and short-circuits the whole time!
You must also provide enough electrostatic shielding in your circuits. This means, make sure all "ground" pins of the components, starting with the one from the output jack, are connected together, without making any loops. You should encapsulate the entire circuit in a "cage" of foil, preferably copper foil, but I have always used aluminum foil with success. This foil must be connected to your circuit's ground. You should also use coax cable for the longer signal connections, and connect the outer conductor of these cables to the ground too (on one side). If you follow all these directions, your guitar will be practically hum-free. If you don't, you may have to pick your strings with a chainsaw before the signal level exceeds the noise level.
Because lots of people mail me with questions about electrical schemes, here's a page with some basic schemes like volume and tone controls, and the complete scheme of my second guitar.
If you have no experience with electronics whatsoever, you may want to take a look at the following book, which tries to fill the gap between zero knowledge and the typical academic books of a frighteningly high level. The book's site also has a links page with a section dedicated to guitar circuitry.
Electronic Circuits for the Evil Genius: "Beginning Electronics 100% Hands On! No previous knowledge required. Being self taught, the author experienced many common beginners' errors. You avoid those while you learn Beginning Analog & Digital Electronics. You develop a depth of knowledge quickly. It is written by a teacher, not a techie."
Other components
Next to the electronics, there are the other components, namely the tuning posts and the bridge. For the tuning posts, there are two options: you can put them all at one side (like on most Fender models), or three on each side (like on most Gibson models). Don't forget this when you buy them!
I used Shaller tuning posts for both guitars, and I'm satisfied with them. The first guitar had chromed posts, which costed around $45. The second one has copper posts, of about $65. Of course, there certainly are other good brands available. Just don't try to save money on cheap stuff, quality simply is not for free.
I made the bridge of my first guitar myself, but I don't recommend this. It's partially made out of wood, and this does not allow the use of heavy strings. However, it is fully adjustable in height and individual string length. The bridge of the second guitar was a second-hand one, probably from a Stratocaster-type guitar. I don't know how easy it is to find new bridges, but they must certainly be available, be it as replacement parts. Mind that there are three types of bridges:
-The simplest, with no tremolo: these must only be secured tight on the guitar body.
-Tremolo bridge type "Stratocaster": these run through the body, and are connected with steel springs at the bottom. These springs keep or pull back the bridge in place. This system has the disadvantages that it must be well-balanced to be stable, and that the strings tend to lose their tune quickly.
-Floyd Rose tremolo bridge: these consist of two parts: the bridge itself, and "locking nuts" at the top of the neck. The latter are secured after approximately tuning the strings, and then the fine-tuning is done at the bridge. This system is much more stable than other tremolo systems, but is more complicated (= expensive) and it takes a bit longer to replace strings. I haven't used it yet so I can't tell much more about it.
Most music stores with a large supply of guitars should also have guitar parts. It may also be interesting to look for second-hand parts, e.g. from people who have guitars that are damaged beyond repair. Just test such parts thoroughly before buying them!
Painting
It speaks for itself that you test your guitar thoroughly before thinking about painting. You may need to file off some sharp corners, or mill away some wood to adjust the balance, and these aren't good ideas when your guitar would already be painted with an expensive lacquer. Before painting, sandpaper the entire guitar body: start with rather "rough" paper, like P100, then use P360, and end with P600 or even P1000.
"The Guitar" by Ralph Denyer provides some useful information about painting your guitar. I painted my first guitar with ordinary spray cans. However, because the wood absorbed the paint so thoroughly, I had to spray a lot of layers before the result was decent enough. The massive amount of paint took months to dry completely, and is not very scratch-resistant. When painting some speakers with spray cans recently, I experienced the same phenomenon: spray can paint tends to take a very long time (I'm talking months here) to harden completely, and during this period it's very vulnerable. In other words: I disrecommend using spray cans, unless you use special lacquer paint and you know what you're doing.
The second one was painted with car lacquer by a specialized airbrush studio, and this is definitely the way to go with solid-body guitars: the paint is much more scratch-resistant and will wear off much slower. If you have the tools and the experience, you can do it yourself. (Mind that you may never mix or overpaint single-component paint with two-component lacquer!)
Otherwise, make a sketch on paper, or on your computer, of what you would the finishing to look like. Take this sketch and your guitar body (without any components of course!) to a paint studio and explain your wishes. Mind that it'll cost a lot (I paid about $200, you should not go much higher than this), so if you plan to make several guitars, you may consider buying the paint tools and doing it yourself, which will be more profitable. In the case of one guitar, however, having it done will be much more profitable - and safer. If you only want a single tint on your guitar, with no effects, you may also try asking a garage keeper who has a spray cabin. This may be cheaper than, yet as good as a specialized studio.
When the painting has been done, you can use car polish to polish up your brand new guitar, and then re-assemble it... and finally play it!