Carbon fibre cloth

[Tristan Croll]

Hi guys,

It's not exactly timber, but it was the closest topic I could find...

I've heard a bit lately about people getting good results from violins made from carbon fibre. I have a bit of free time coming up, so I figure I may as well have a go at building one myself. My questions are:
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Does anyone have any experience working with the stuff, and can offer advice?
What sort of price per metre am I looking at?
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Thanks,

Tristan

[Iain]

I believe that working with carbon fibre is almost exactly the same as working with GRP (fibreglass). It is a mat woven from carbon which is the same make up as GRP and comes in as many different thicknesses and weaves.
I do know that carbon fibre has a shelf life unlike GRP and must be used before the expiry date. I do not know the consequences of exceeding the use by date. The resin I am not sure of but would be obtainable from the supplier of the fibre. The DuPont web site would probably be a good start because if they don't make it, it probably doesn't exist.
As for working with it, have no idea but I would imagine it would be similar to GRP, I have seen carbon fibre fly rods being made when I was in the uSA and it did not look difficult, I am also sure that it probably is harder than it looks.
I would get a book on GRP moulding and a book on violin making, particularly for the contouring and thicknessing of the soundboard.
Bear in mind that the accoustics/resonances are more than likely to be totally different and the existing manufacturers are not going to be giving too much away.

Heres a site to run up your internet bill http://www.fibreglast.com/fiberglass_repair.htm#Online Brochures

[This message has been edited by Iain (edited 19 June 2001).]

[Pete]

Tristan,
some years ago I was visiting the CSIRO in Melbourne and they were doing interesting work using Carbon fibre composites, maybe they could point you in the right direction. The CSIRO web site is http://www.csiro.au/

The plastics boys have a link from the main page. Could be worth a look.

Cheers,
Peter

[Tristan Croll]

Thanks for your help guys.
There are actually a number of sites on the Internet with plans for violins (for a small http://ubb.ubeaut.com.au/ubb/rolleyes.gif fee). There's also a company in the US of A making carbon fibre violins that are attracting professional interest (at least according to their website). Apparently you can drop these things from shoulder height onto concrete and they won't even go out of tune.

Thanks again,
Tristan

[AlexS]

Tristan, if I was playing the violin, you could drop it from a 10 storey building and not notice if it had gone out of tune.

Why not just by the materials and fiddle with them? (boom boom)

[Iain]

Must be crappy strings they are using if they don't go out of tune. My Rimarez guitar goes out of tune if someone opens the bloody door and the temp changes by about 2 degrees.
I might ask my brother about violins, he tormented one for a few years before we shot it.
Honestly though, if it stays in tune that well the soundboard would not be that good and resonance would be very limited and advertising claims have been known to hold a few 'untruths' in the past.
I recall when we sold a house some years ago we saw it advertised by the agent and it looked like just the palace we were looking for!

[Tristan Croll]

The most important factors in choosing a material for a good violin (or guitar, for that matter) are lightness and stiffness. Lightness, so that it has very little momentum and hence flexes easily, and stiffness so that it vibrates, rather than just stretching like wet spaghetti.
Carbon fibre has these properties in spades. It is probably the first known material that can compete against wood in making acoustic instruments.
There are also some advantages in using it as opposed to wood:

It is essentially impervious to changes in humidity (violins, being unsealed on the inside, don't take humidity changes well at all);
Actually, it is completely waterproof, so that the instrument could theoretically survive a dunking in water;
It has a low(er) thermal expansion coefficient, that is it does not respond particularly strongly to temperature;
It is extremely strong, so it does not have to be treated with kid gloves, like a standard violin; and
Perhaps most importantly, I love the idea of playing an instrument that I created myself, and I know for sure that I do not currently possess the expertise, equipment or money to make one out of wood.

Just thought I'd clarify a few issues.

Thanks again for your comments,

Tristan

[Iain]

And having said all that, from one who has played concert guitar, all the theories are shot down in flames when it comes to a good instrument and defy all comprehension.
Two instruments can be made from the same piece of timber by the same person and cut and assembled at the same time, both can be finished with the same finish mixed at the same time and you can bet that the two instruments are going to sound different.

[RFINK]

If God has meant us to make violins out of carbon fibre He would have made carbon fibre trees.

[Tristan Croll]

RE Iain's comment:

Tell me about it. Believe me, I know, having played various violins for twelve years now. [i](Wow, is it really that long? http://ubb.ubeaut.com.au/ubb/eek.gif ) It's said that the incredible sound of a Stradivari comes not from any radically different technique, but rather from slight variations in thickness across the belly of the instrument. When it comes to sound quality, the smallest details can make a huge difference.

[This message has been edited by Tristan Croll (edited 24 June 2001).]

[Iain]

I thought the findings on the 'Strad' were iconclusive but with many theorising that the sound quality came from the lacquer.
I trust you are referring to THE Strad and not the Australian variety circa 1900.
A guitar is a different propostion and has a life of about ten years from manufacture, five years improving to peak and five years deteriorating. Makes it an expensive proposition with my forty years of playing.
I am referring to a classical guitar.

[Richard Casey]

Interesting subject guys. I have a mate that plays with carbon fibre, and its greatest problem, is that it must be set under a vacuum. Also remember reading that the Strad's sound comes from the timber they were made from, due to climatic conditions that have never been repeated.

[Westie]

are you attempting to make a purely acoustic instrument? A guy who occasionally jams with us has a violin which is just a big chunk of fibreglass with a couple of pickups set into it. It is shaped like a huge dollar sign ( questionable taste, but man can he play ) Rainsong guitars have been building carbonfibre acoustic guitars for 20 years now and people who like them swear by them. What about the neck? Would that be carbon fibre also? or would you use a more traditional material? I'd be interested to know how you go
Cheers

[Tristan Croll]

Accoustic, definitely. When talking about electric, pretty much anything goes.
The basic sound of the violin is actually generated almost completely by the action of the strings and the bridge - the body is just there to amplify the sound. It is the preferential amplification of different frequencies that gives each violin its unique tone. However, this also means that you can make a decent-sounding electric violin that is simply a stick with strings (or a dollar sign, as you said). My personal favourite is the Stingray (http://www.starfishdesigns.co.uk/EBIPIC.HTM), made by a crowd in England.
Basically, electric violins come down to imaginative carving, and can look like pretty much anything you want.
Anyway, while an electric violin is also a project I have slated for the future, for the moment I'd like to try a true accoustic. Main reason is that an accoustic doesn't have to be plugged in.

Oh, and by the way:
For anyone who's interested, a quite servicable audio pickup can be made for less than $5 using the little piezo buzzers sold at Dick Smith's. Like any piezoelectric crystal, these vibrate in response to a varying voltage, but also produce a varying voltage in response to vibrations. In short, solder a wire to each side, stick it securely to a point on the instrument, and you have a near-professional quality pickup.

[djsedge]

Tristan - if you really want to find out about this stuff go and find an up market boat builder. These guys have been using large amounts carbon on racing yachts and skiffs for years. There are even making masts out of it now.

Cheers

David