Homemade Cutaway Guitar - of an Existing One!

Intro: Homemade Cutaway Guitar - of an Existing One!

These are instructions how to make a homemade cutaway guitar of an existing one.

CAUTION: Not for beginners!

You must be able to handle with wood etc.

Get a guitar
http://www.ebay.com
http://www.ricardo.ch

A Guitar
http://en.wikipedia.org/wiki/Guitar

General documentation
Acoustics for violin and guitar makers
http://www.speech.kth.se/music/acviguit4/

STEP 1: What You Need

Ok, here is what you need:

1 existing Guitar. (cheap one!)
1 Hotair gun
1 Saw (here japanese)
1 thin small saw (here a automatic). Needed for make small radius cuts. [german: Um sehr enge radien zu sägen.]
1 glue
1 paring chisel (small one, here 6mm) [german: Stechbeitel]

+ Lot of patient and time ;-)

STEP 2: 1st Do Checking and Draw a Mask

First do checking if the cut is practical. If you can do it.

Check for parts witch must be cut off.
Check for parts inside the guitar.
Check also witch side. Left hand or right hand guitar differs!


Prepare a mask, a template. With paper or with transparent foil.

Draw with little dots the "cut route" on top and on bottom of the guitar.

Make sure, that you will saw better less material then too much!

STEP 3: CUT!

Do the cut! - But think better twice then ... cut away material that you need (as I did unfortunately)!

1st the top, then the bottom, then on the neck. NOT the side! (The side will be bent.)

STEP 4: Prepare for Bending

So then, do preparation for bending the body sides (ribs). [german: Zarge]

Clean up.
Remove the paint (german: Lack) on the body side.
As shown in the picture.

Depending on what (german: Zargenverstärker ) you have:

• cut them, if not already is so. As shown in a picture below.

The trick here is, that the body side needs to be very good prepared for bending.

CAUTION: Do not bend the body side if dry!

STEP 5: Bend

Bring water on the body side. With a spray.
After a minute or so, the body side is wet and very easy to bend.

So you can just "open" the guitar, so that you can look inside it :-)

STEP 6: Prepareation Again (for Definitive Bending)

Do some preparation on the bottom.

The body side will take place *inside between* the bottom and the top.

So, remove some wood (german: Verstärker oben und unten), if they disturb.

See pictures below.

STEP 7: Bend!

This is one of the most critical part.

• Put water again on the prepared body side.
• You should be able to bend the body side very easily.
• Maybe some heated up air is required, maybe not.
• Make sure, that the body side does not move away.

You see, the body side is broken a little bit. Also some wooden parts disturbs.

You can also see the missing wood of the bottom side. (So better cut away less wood.)

But, anyway does it looks like a cut away right now?!

STEP 8: Glue and Repair

Glue

• I used simple white glue. PVAC. (german: Schnellabbindender Weissleim)
• So in 5 minutes, the glue is dry.

As you can see I cut away too much wood on the bottom side.

Repair

So here the reparation.

• Add wood that was cut way before.
• Glue it.
• Cut away wood. And do preparations with sandpaper.

Comments

[davidapfeiffer]

No bending wood. I used popcicle sticks years ago to fill the cutaway area on the body, some wood filler over them, and then repainted guitar body. Was able to cover an extreme cut easily. Looked great.

[sartor]

This mod will dampen your guitar's resonance and tone! That wood is there for a reason.

A test to see how much the soundboard's resonance affects the sound of a guitar: put a guitar on your lap and strum the open strings. Listen to the vibration, sustain, overtones, etc. Now press your other palm down on the soundboard (not too hard, as you don't want to damage it) and strum again. Hear the difference? Try this with the sides and back, too.

If you MUST have a cutaway (do flat-top guitars sound good that high up anyway?), consider a Maccaferi-style that's not too invasive:

http://upload.wikimedia.org/wikipedia/commons/7/7c/Guitares_type_Selmer_Maccaferri.jpg

[looperted]

Thats the same guitar i have if its an alvarez! =P

[LasVegas]

How severely did this effect the acoustics of the guitar? I'm assuming, being a very inexpensive guitar, it didn't have much quality to start with...

[michi]

As far as I know, the "acoustic" (tone, sound) will be mainly generated by the strings. Yes, this was and is just a test to see, if this modification is possible. I don't know if anyone else did this before. And, as you can see, it was a very inexpensive guitar. About CHF 60.- swiss francs. (Its EURO 40, $60? (what about the dollar? ;) So, just for doing things like that, go to ebay and pay a very cheap guitar.

[mrmath]

I don't know much about acoustics, but I do know that the shape and structure of the guitar has A LOT to do with acoustics. Then again, I don't know if I would hear the difference.

[michi]

I think it's like this: 1. string, tone will be generated with the strings. Best $9000 guitar with bad strings will not sound that good as a $90 guitar with good stings and tuned correctly. 2. top body , manly the top of the guitar inclusive connections (string-to-top). 3. rest. A cutaway is very similar like a normal one. If you change stings or change connection points (string-to-top) it has much more effect. You can also leave away the whole back bottom without that much difference. Sure, with more volume the sound will become more volume, better resonance for lower frequencies.

[Synthezoid]

I'm sorry to criticize, but I have a degree in acoustics (and have also been a guitarist for 22 years), and I can tell you that you are completely wrong in your thinking. The tone of a guitar is produced by the properties of the internal air volume of the body as well as the construction qualities of the box. People think sound production in a guitar or piano is simply a matter of a vibrating string being amplified; this is not how it works. The string provides the initial "push" but much of the sound comes from resonances arising out of a complicated mass/spring-type problem involving the mass of air in the body cavity, as well as that of the bracing, the back, and neck, and is strongly dependent on that cavity's shape and the guitar body's construction. Your statement #1 about the $9000 guitar with bad strings versus the $90 guitar with good strings is not just untrue, it is factually impossible because of the differentces in construction.

Strings and connection points affect volume, partials and sustain greatly, but not so much the overall tone (at least, as long as you're not comparing strings with two completely different vibrational properties, like nylon vs. steel and wound vs. unwound or roundwound vs. flatwound.) I use the exact same set of D'Addario medium strings on my old beater Epiphone and my beautiful tobacco sunburst Simon & Patrick dreadnaught, but both guitars have a *completely* different tone from each other, owing to their different construction.

A lot of this can be found right in the "part 6" pdf on the acoustics page you linked to above (http://www.speech.kth.se/music/acviguit4/). (See in particular where it talks about how important the back and neck of the guitar can be to the resonances that shape the tone.)

Generally speaking, the smaller "bulb" of the guitar's body (near the neck) produces a high-frequenecy resonant peak, and the bigger bulb produces a lower peak. Together these produce a full sound. (This is why you rarely see "teardrop" shaped guitars, like an "A-style" mandolin.) Change the volume of one part of the cavity and you change the mass of the air that occupies the body, which shifts the resonant peaks and changes the tone. Ditto for removing mass or changing the shape of the front or back. Even the mass of the guitar's neck makes a difference. (See the PDF again. Or, if you want to try an expensive experiment sometime, stick a Stratocaster neck on a vintage Les Paul and see what it comes out sounding like.)

The reason cutaway guitars are more expensive than non-cutaway guitars is because of the extra work required to compensate for the acoustical losses of changing the body cavity volume and the area of the top, the necessary extra load-bearing bracing for the neck, etc. True, the losses may not be that huge to untrained people's ears, but they are there, and in a fine guitar it can create a noticeable difference.

These are not my opinion, they're simply the scientific facts of how sound production works in a guitar.

If your guitar sounds the same to you after doing this mod, I'd argue you probably have either a pretty cheapo guitar or a fairly untrained ear. Nothing wrong with that, except that it's incorrect to say on the basis of it that this won't change your guitar's tone.

The upshot is - thanks for this instructable, it's great (and a bold move!) but people should be warned not to do this to an instrument they care about, because the results will be unpredictable. Real cutaways are designed much more carefully than this, they're not just a regular guitar with a chunk taken out..

[RC-Roi92]

Where does one acquire a degree in acoustics? That sounds like an awesome field of work :D

[infoplus007]

The basic idea is very good, ans Iwill try it on one of my cheap guitar ( classical Spanish), Sure the tone will "move" but if you think twice when the guitar is open you can take à look at the "brassing" of the guitar and make it better, to add some high frequency. For the low end cutaway under $500.00US, they don't redesign al the guitar simply adjust the bracing and add/remove the cutaway. Over 800.00US now the guitar plan take in account that's will be a cutaway guitar. That's my point of view. Great Idea on cheap guitar but not for my Takamine ;-)

[trebuchet03]

Strings are going to play a large role in tone etc. Similarly, reeds will do the same for woodwinds. Etc. etc. But the nice little resonant nodes that come from a great design make an instrument valuable.

Instrument materials, shape, construction will play a huge role in resonance (as you probably know). Sure, you can get decent sound out of almost anything by being a good player and using quality (not necessarily expensive) consumables. But comparing the same consumables on two different designs can show a big difference, if you know what to listen for :P But don't get me wrong, I spent a decent amount of money on a euphonium mouthpiece :P

Kinda like speakers.... Pay hundreds for the driver speaker... and a few dollars on an enclosure -- and you're not going to get as great a sound out of it. The Bose wave thingamabober is all enclosure (instrument), less driver (strings) - for example.

Nice instrucable though :)

[binnie]

you can have cheap speakers but a well built enclosure and the speakers will sound alot better than they realy are

[trebuchet03]

Yep, that was my point :)

[carlos66ba]

Come on michi, if this was the case there would be no difference between a Guarnerius violin and a "el-cheapo" one... The box does have an effect!

[michi]

*lol* -
Yes sure. But on a existing one, the cutaway will not take affect strings and connection points etc. - Only shape and volume a little bit. So, the sound is nearly the same as before.
In fact, I was able to clean up and finish some wood splitting inside the guitar, witch did some noise before. ;-)

[Wario]

I personally would not do this, it would deminish the value of the instrument. Besides, i don't notice a diffrence between the two types of guitar. Other then that a brilliant instructible.

[Ramnosity]

You said you did't notice a difference. I cutaway lets you get down to those really high strings. Mostly seen on electrics or electric-acoustics

[Wario]

im actually used to reaching over the noncut region of the guitar.

[downhilldman]

me too

[Wario]

Oh yeah, i forgot