A Carbon Fibre Violin I Made From Scratch

Last year i made a carbon fibre violin ,
I started out  by drawing a violin on paper ,  working out the curve heights , plotting the lot on paper ,

Once i had my plans drawn it was time to start making moulds , the violin plate moulds started as block of plaster , that i routed out and fine carved to produce a "plug" , the 1st mould was taken off that  , then fine finishing the top and bottom plate  mould  took about 1 month , and i  still had a lot of fibreglass moulds to make , rib mould , neck mould ,   finger board mould, they all take time. ,
To have a Shop Bot would be a huge help with the mould making  , change the shape slightly on the CAD drawings ,rerun CAM , and watch the Shop Bot produce its magic on HDPE ( only a dream )., using a Shop Bot to draw perf lines , and trim the carbon fibre , i wish i could afford one .

The first plates i made from carbon fibre were way to stiff , "tap tone's " told me it was better used as a brass bell than a violin , after producing about 10 violin plates i was getting into the ball park of tone , a combination of different materials  , laid down in different thicknesses in different areas produced a violin front and back plate i was happy with .

I used the infusion method of carbon fibre making , were you lay all your layers up dry and vacuum bag it , once the vacuum is over 25hg (-12psi) you open the tap to the resin , and the vacuum pulls the resin into the carbon fibre fabric , the laying up of the rib mould took me 5 hours each side to get the fabric to sit in the right position , very fiddly ( pardon the pun) .

The gluing jig was made from MDF with 10mm cup heads sticking through , designed to allow side ways positioning of the rib and neck parts , and the holding down clamps for the top and bottom , the centre part  of the jig was removed to glue the top on, with the 4 hour set time of the resin ,its important to keep it all firmly heard in position. 

The cutting and shaping of the f holes is another reason they call them fiddles , carbon fibre is a bugger to cut , found that if you submerge the carbon fibre in water and use a Flexi Drive bit holder on a Dremmel, it keeps every thing cold , and produces no dust , just ware a rain coat 

After a final coat of clear and a polish it was ready to string up and hand over  too some who who could play it , ive had grate feed back and a few offers for this violin and at the moment are remoulding for violin 2 ,working on the  2nd set of plans  now ,drawing them up on a  low budget Cad , AutoCAD would be a big  leap for me and  used with a Shop Bot would speed up design changes 100 fold , and allow me to produce Cello's and Violas .

All up it took me 10 months of Sundays , from the time i decided to start to finished product , i had never made a violin before , and my carbon fibre skills were below basic , it was a huge learning curve but between the info on the net and getting your hands dirty and " givin it a go" , anything is possible

Dont forget to vote for this ,
by Ken Van Laatum 

After purchasing a good violin making book or 2 , i set out to draw a violin ,not an easy thing to do. 
All the compass work comes from a single measurement , the centre measurement of a violin bridge's feet ,that measurement is ether 2x 4x ect and the shape comes to life with the golden spiral rules . 

The length and 8 widths were measured and the curve shape plotted , the 8 different width positions have different heights set from the length curve , once all the curves were plotted it was redrawn on a second plan as 2mm contours so a router could rough out the Plug for the mould 

EDIT : 3.34AM 10th12/11

I down loaded a Mp3 of the open strings of this violin to make all the rioting people happy , 

please take the time to log in and vote for this instructable,  as it is a competition , and I would like to win  :-)

You have to make exactly what you want , then take a fibre glass mould from it , the original object can be made from any thing , plaster , wood , wax , 
The top and bottom plate mould started off as a block of plaster , while it was set but sill moist i roughed it out with a router and smoothed out the contorts with a chisel , once the plaster had dried it was sanded filled  and sealed and polished to 1200 grit before fibreglass was laid over it to produce the mould . 

The rib mould was 2 layers of  16mm ply laminated together , planed down to a wedge shape , then cut to shape with a band saw , once the "Plug" was sealed and polished it was placed between 2 boards and fibre glassed up to produce the mould 

The neck i carved out of timber , with mould making you have to look out for your angles , you cant under cut your mould or you wont get the finished product out 

Dont forget a bond beaker on you r"plug" , there are many different types but i found PVA mould release easy to use  

Once you have your moulds made your 1/2 way there , if you look after your moulds you will get several "runs " out of them 

Carbon fibre is not as expensive as you might think , and readily available on the net , my violins use less than 2 square meters of carbon fibre cloth 

Carbon fibre comes in many different fabrics and weaves , ill leave it the net to explain the "K" and weave patterns and there uses.
Basicly Carbon fibre cloth is like any other cloth (soft) and once its set in resin ,it gets its strength  , its the strength and acoustic abillitys of the resin that is important , fibreglass polyester resin is no good , epoxy must be used , there are several was to make carbon fibre ,

Wet lay up , is when you wet down the fabric with a paint brush and lay them up , place a peal ply over it , an absorbent layer , then plastic vacuum bag it up and suck the air out , the pressure from the vacuum bag forces the excess resin through the peal ply and into the absorbent .

Infusion , is when you lay it all up dry and vacuum bag it , waiting until the vacuum is high before  allowing the resin in through a tap , once the mould has been infused you close the tap and pull a good vacuum on the mould , i like  this way because it gives you lots of time to lay the layers down and your not running around like a mad man if your vacuum bag has a hole in it .

Prepeg is the professional  way , manufacture has wet it down with a resin , most need ovens and autoclaves , it must be stored in a freezer even then the shelf life is short 

i put down 3 layers of clear before the carbon fibre so the parts come off the moulds just needing a polish 

The jig i came up with has 2 parts , the centre part can be removed once the bottom is glued on , so you can turn it around and and bolt the top and neck down on the same jig 

The side ways threads hold the ribs in the correct position so they can be joined and and hold them inplace while the bottom plate is glued on .

Give it a good polish and your done 

This"How too" is in response to people asking how i drew my violin , its not a strad 

I call this a 1234 design , if you use this to make a violin , please call it a "1234" design 
its quite simple and basicly  shows how the shape comes around using the golden rules where each radius is 1x  2x 4x 


To start off you need a measurement to start , so measure the bridge , you want the centre of the foot stance , on my violin its 32mm 

so starting at 1/2 , 1 , 2, 3, 4,  the measurement  you get 

16mm ,  32mm ,  64mm , 96mm , 128mm , these are the radius of your circles 


To start draw a 32mm radius circle on a centre line about 200mm right of the edge of the page (A3)

Now draw 3 circles at 64mm radius , these mark the rib wall at the widest point , and the 3rd is needed to get a line for bout position  
i will show the new circles in blue and the centres as black dots , they will turn black for the next step 

2 more circles at 128mm  , these mark the out side rib edge where the bout circles touch 




 

now 2 lines , these mark the position of the lower bouts 

this circle's radius is best fit ???? well it seems the best spot for the centre , it marks the very bottom of the violin 





  

Now its all looking like a mess ,  so what ive done is to draw the rib outline in black , and reduced the construction lines to yellow , just so its clearer 

Now its time to draw the the upper side of the violin ( still could be a guitar ? double bass ? cello ? viola ? if the 1st measurement is modified ) 

The only difference with this side is that the starting circle is 1/2 the size on the upper , than the lower 

Its best to draw it all out , and measure the distance from the the " Bout arcs " crossing point to center ,
We are looking to over lap the top and bottom halves by 1/2 the bridge foot centre  measurement ( 16mm ) 


so from the bout arc cross over point  ,  measure out 102.6mm from the dot on the last image , and draw a circle  16mm diameter 

we now have to redraw what we have in a mirror image of the lower 1/2 , i wont just rush and draw it all , ill draw it out , bit by bit 

so were up to the 3 circles again , there the same size as the lower 1/2 at 64mm radius , but there centres are 1/2 the distance apart ,making the top smaller than the bottom 

now we draw 2 circles , these mark the out side rib edge where the bout circles touch, there 128mm in radius  , they should cross the lower lines  by 16mm   ( blue dots ) 
 

Now we are about to draw two straight lines , that mark the positions of the upper bouts 

now the the arc that forms the very top curve , the top plate is left as it is ,  the bottom plate has to have a arc to accept the lower part of the neck 

Once again now its all looking like a mess ,  so what ive done is to draw the rib outline in black , and reduced the construction lines to yellow , just so its clearer

Guitar builders can work it out from here 

The violin needs some bouts , unless there a carbon fibre violin maker who thinks a " 4 string small guitar" = a violin , now there size and combination are up to the maker , 1x , 2x  , its up to you 
the radius's are 16mm or 32mm 

Start on the outer most circles , and match the inner ones to where the lines cross 

A word of warning , if you do make a carbon fibre violin ( small 4 string guitar ) without bouts , you might ( you will) infringe apon a USA's company's patent , check weather the major Carbon fibre violin ,  cello ( 4 string guitar maker ) maker , has bothered with a patent in your country  ( they have in mine )
Read there patent , 

Time to fill in the bouts , 64mm radius circles 

So now the bout lines have been simplified to the rib edge line , and another line 3mm away forms the outside eadge of the violin shape 

The flat side's of the bouts are always a challenge to get right , the best way is to run a line from the opposite  top or bottom centre to miss the rib out line / block by 3mm

the top 1/2 and the bottom 1/2 of this drawing are diffident around the the top bout area , i personally like the top 1/2 , so will modify the drawing to be the same top 1/2 and bottom 1/2 

This is the basic out line of the "1234 violin "  , the same as the my plan of the violin , on the second photo , it shows the out line against an ebay purchased "Strad template " , its not that far off but it is not a Strad 

If you want your brain to hurt , you can modify the size of the circles , some thing ive been playing with ,is trying to draw a STRAD by modifying the circle size by the ratio of a guitars frets   on a guitars finger board 
So if you divide a string length by 17.817...... (magic number) , take that length off the string , you will end up with tone 1 note higher 

This "how to" is all my own work , and i challenge anyone to search the web for a web page that shows  " how to draw a violin with a compass" , there are 2 images of finished drawings , very complex , and are the result of reverse measuring an existing  famous violin  , it took me about 3 months to work this way out from those 2 images  , some of the other books ways of drawing violins refer to drawing angles down to the 1/100th of a degree , imposable with a pen and protractor 

If you use this "how too " please call the shape a "1234  32:16overlap violin " starting with a larger measurement should result in a larger instrument , viola , cello ,  double base , quad base  the octobase is just plain unplayable 

The violin consists of a 3d curve , back in the 1700's sound did not travel in a sine wave , so they tinkered with the plate shape for over 400 years and got pretty dam close to sine wave , the purest's will shoot me , but since im not making my violins out of timber , there not on my side any way .

The plate shape all starts with a curve from top to bottom ( see 1st pic ) , the sine wave curve and the rib-line meet , the 3mm over hang side starts to turn back up , around the bouts ( pointy bits on the side ) it cuts the corner , so all the curves lowest points are at the rib-line or the inside of whats called the" block" ( a block of wood on timber violins , the bouts or those pointy bits on the side )

There are lots of sine wave plotters available free off the net , you just have to enter length and height 

Start with the long sine wave, i used the height of 16mm because its 1/2 of the measurement we set the hole violin out with   ,  at 90 deg to it set out your "width " sine waves ,getting the height of each one from the long sine wave 

Keep plotting your sine waves , or just scale them to fit perfectly  (pic2)



Then lay a mesh over the top , and set the Zaxis points to match the sine waves (pic1)
have fun , this drawing took me 2 months , over 7000 points all raised up to correct height 

Once you have your 3d drawing , its off to the machining shop , or you could hand carve it like i did the with my first violin 

The image has to be ran through a CAM program , and then its off to a CNC machine to be turned into reality 

The first mould i every made was made from plaster , and it took me a lot less time than drawing a full 3D plan in CAD 

The sine waves were plotted on paper , and measurements taken in 2mm increments , and a contour plan was drawn  

The contour plan  was laid over a block of plaster ( 2nd mould was WAX ) and a hand herald router was used to rough out the contours , then chiselled into shape , and sanded smooth 
Then it had to sealed and mould release applied before  a fibre glass positive  mould was then taken from it , then the positive was sanded  polished , sealed and moulded to get the negative mould i used 

It wasn't that much faster , the drawing was fast , but the sanding was endless , with the CNC ones , the drawings took for ever and the moulds came back smooth 

So now you have your polished  mould , your 1/2 way there 

In the image below , the mould has had a coat of PVA based mould release , and coated 3x with clear epoxy resin , dont confuse epoxy resin with fibre glass resin , there different , select the hardest epoxy resin you can find ( MPA) , the harder the more resonate the violin plates will be , im using West System's 105 here with there 108 hardener , its easier to tone them down by playing with the  layers 

You have to allow each coat of epoxy to "jell " before applying the next coat , if you let it go hard , some bad stuff forms on the surface , and your layers will peel off 

Once the 3rd layer of clear has "Jelled" , you can lay a layer of Carbon Fibre cloth over the mould , and pat it down to the tacky clear coats , it will stick so 4 hands are needed 

Slowly pore a tiny amount of resin into the middle , and wait , the resin will flow into the first layer , you do not want to trap air in under the fibre , take this part real slow , pore some more resin and the middle and wait again for it to wet down real slow , do this about 5 times untill you have a puddle in the middle , with a paint brush , slowly pull the resin out of the puddle and up the sides , allowing enough time for the air to escape working out would from the puddle 

When the first layer is totally  soaking wet , add the second layer , you should be able to use the existing resin to wet out that layer ( a lot faster) , and keep on building up the layers until your happy , try different cut outs , different materials  , carbon comes in a huge amount of weave patterns and each has its own properties  that affect tone 

After the laying up of the carbon fire is complete , a layer of "peel ply " is laid over the top , this membrane allows the resin to pass though but wont bond to the resin , it can be peeled off later 

1/2 inch Dacron is used to absorb the excess resin , it works well , it stays flexible where cotton rags will set rock hard  

The mould is then placed into a "Vacuum bag" , and a vacuum pulled to over 25Hg/in , this compresses all the layers together , with the excess  resin flowing through the peel ply and into the Dacron , the Dacron also helps to get an even vacuum over the hole surface 

In this photo ive used Forticon concrete underlay plastic , but now use a nylon super stretch bag material 

When you make your bag up , leave the front edges "Mastic " with the non stick tape left on , its a lot faster to seal , this mastic is easy to use , its also easy to repair leaks when the vacuum is pulled   

The vacuum pump is one of those electric pumps refrigeration mechanics use to suck the air out of a air-conditioner before re gassing , with a filter and " resin Catch Can " installed before the pump 

A few hours later when the resin has set ,( resin left over in mix container  is hard )  it time to strip the mould , grab the peel ply and rip it off , taking the Dacron with it 

Before the resin sets real hard brake the bond around the edges of the mould , but dont remove the carbon fibre from the mould until 24 hours has passed , its easy to damage it when its still soft 

24 hours later pop it from the mould , they come off quite easy , the "Blue PVA mould release" is good stuff 

Iif your mould is polished the finish is perfect , a lot easier to have a smooth mould than to sand , and fill the carbon fibre parts