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Davide Sora's bench


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57 minutes ago, charliemaine said:

What pigments are you using to achieve such a lovely red color?

As for pigments I use a mix of madder and cochineal, but the final color is due to the sum of many factors, like the color of the wood, of the resins, the position of the colored layers in the overall thickness, and not least the rendition of the PC screen: I hope that what you see is similar to what it is in reality, but who knows:D

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41 minutes ago, Davide Sora said:

Regarding madder, I also use it fixed on iron to cut the excessive brilliance of the red. In small quantities, because it's not much transparent

How do you fix madder on iron? Or is this something you buy? So you cut the brilliance of the cochineal with it? Would mixing in a little brown iron rosinate with the cochineal accomplish this too?

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3 hours ago, charliemaine said:

How do you fix madder on iron? Or is this something you buy? So you cut the brilliance of the cochineal with it? Would mixing in a little brown iron rosinate with the cochineal accomplish this too?

The procedure is the same as with alum, simply using iron sulfate (green vitriol) instead of alum. I use it to cut the red, both of the madder fixed on alum and of the cochineal. The iron rosinate, at least the one I made, is too light as brown to be effective, while with the madder on iron sulfate I get a very dark brown, with a slightly greenish cast.

I must say that by making the pigments by itself it is practically impossible to obtain the same colors twice, but by making several batches you have different shades available.

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1 hour ago, Davide Sora said:

The procedure is the same as with alum, simply using iron sulfate (green vitriol) instead of alum. I use it to cut the red, both of the madder fixed on alum and of the cochineal. The iron rosinate, at least the one I made, is too light as brown to be effective, while with the madder on iron sulfate I get a very dark brown, with a slightly greenish cast.

I must say that by making the pigments by itself it is practically impossible to obtain the same colors twice, but by making several batches you have different shades available.

I'm using Kremer made madder and cochineal lakes and they're working fine. I use the cochineal sparingly to bring out a little more red when needed. I have brown iron rosinate if things get to garish. Thanks for the useful info! 

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  • 3 months later...

I made a couple of videos while I was finishing the F-holes, the last varnishing job I do before making the set-up. It will probably seem like obsessive overkill to many, but well, that's the way I like them.:)

 

1) Elimination of excess varnish and application of a protective coat:

https://www.youtube.com/watch?v=FzERvrHexrc&t=54s

 

2) Application of the color and finishing of the edges:

https://www.youtube.com/watch?v=-SAKcv1SFz0&t=17s

 

Finishing of the inside of the F-holes - Condensed version

https://www.youtube.com/watch?v=DVem-PdhklA

 

 

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  • 2 weeks later...

I'm using the method mentioned by Claudio Rampini 

First you need dry linseed oil,  you can do this by putting it a pan in sunlight in the summer, stir occasionally as a film forms on top alternatively his instructions are to paint layers on a cloth daily allowing it to dry.  Once dry it will dissolve in an alkaline solution.  Then precipitate with an acid.  The precipitate will then be soluble in alcohol.

The drying process may take a few weeks or a month or two during summer,  winter too I guess but in Georgia we get lots of sun and UV in the summer. 

I used low quality hardware store boiled linseed oil but in the future will be using good quality washed oil.

I don't have 30 years to wait either,  I figure I've got at most about 20 years before I get to meet Stradivari in person.  Then I'm going to ask him what he used for a ground layer!  :D

See my build thread for more instructions.   

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On 11/3/2022 at 4:40 PM, charliemaine said:

I like the color changes. At what point in time is it alcohol soluble and how do you make this into a varnish? Are you cold solving in other resins? 

 

The time may vary depending on the environmental conditions, the type of oil, whether it was cooked or raw at the beginning of the process, the thickness of the layers and the consequent contact with the air, etc.

But I think a time between 5 and 7 years is probably enough to get alcohol solubility.

To make the varnish I combine the resins practically cold, I boil only a little but the boiling temperature is so low (80° more or less) that it cannot be considered a real cooking.

You can see how I make my varnish in the videos gathered in this playlist:

 

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22 hours ago, MikeC said:

I'm using the method mentioned by Claudio Rampini 

First you need dry linseed oil,  you can do this by putting it a pan in sunlight in the summer, stir occasionally as a film forms on top alternatively his instructions are to paint layers on a cloth daily allowing it to dry.  Once dry it will dissolve in an alkaline solution.  Then precipitate with an acid.  The precipitate will then be soluble in alcohol.

The drying process may take a few weeks or a month or two during summer,  winter too I guess but in Georgia we get lots of sun and UV in the summer. 

I used low quality hardware store boiled linseed oil but in the future will be using good quality washed oil.

I don't have 30 years to wait either,  I figure I've got at most about 20 years before I get to meet Stradivari in person.  Then I'm going to ask him what he used for a ground layer!  :D

See my build thread for more instructions.   

The system of the canvas works well to speed up the times, because it allows to make very thin layers and to increase the surface exposed to the air. it is the system that was used industrially to make linoxin for the production of linoleum. The system of saponification with an alkaline solution and subsequent precipitation with an acid solution also works and can be used successfully.

But natural oxidation has the advantage of obtaining a darker and reddish color, and a better consistency and elasticity of the linoxin. With saponification the times are shortened but the color will be lighter and yellowish, and the linoxin will be softer and more heat sensitive, so the composition of the varnish will have to be adapted accordingly and basically the varnish will be a bit different.

Then, exposure to the sun is something I wouldn't recommend if you want to get a darker, reddish color, as direct sun will lighten the oil, a process well known to oil medium makers for painters, who were meant to make it as colorless as possible and to avoid yellowing not to spoil the pigment colors and brightness, but in violin making the opposite seems to be desirable.

My linoxin is made by keeping it away from light, almost in the dark in a well-ventilated and warm room, placed in high position to keep it as warm as possible.

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22 hours ago, MikeC said:

Thanks for the comments Davide, I had mine in the sun for the UV but once dry I now store it in a shed where there is no light.  I wish I had started some many years ago but I didn't know about it back then.   

I came across the little book published in 1986 by Lapo Casini on linoxin in that same year, it fascinated me and I immediately got to work on 2 liters of linseed oil. I had tried all things described in the book, maceration in alcohol, saponification with various types of alkali, natural system, but without obtaining positive results other than a big mess, as happens to almost everyone when one is at the beginning and inexperienced. So, a bit upset,  I gave up and for many years I "forgot" the many containers of ground Linoxin on the shelves, and only in 1992 I looked back at them again and I realized that something had changed, the linoxin had become much darker. I had tried to dissolve it with the alkali/water solution and it dissolved well and fairly quickly, which did not happen in my first attempts neither with caustic soda. Out of curiosity I also tried to put it directly in alcohol and to my surprise it dissolved completely, thus making the saponification treatment superfluous. So I realized it was just a matter of having patience to wait for the right time, and from 1992 I started using linoxin for my varnish.

The linoxin I'm using now is still the one started in 1986. I will probably run out of it in four or five years, but I already have more in advanced aging phase that will be ready for the future.:)

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Hi Davide

Unfortunately I don't have many years.  So I have to try the fast version.  I have some linseed oil that has been in a pan for about one and a half years since the Summer of 2021.   It is now a dark orange very sticky substance so I can see how it is changing over time.   

I was able to get some of it to dissolve in an alkali water solution and then precipitated it and it was alcohol soluble but there was some undissolved residue in the bottom of the jar.   

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4 hours ago, MikeC said:

Hi Davide

Unfortunately I don't have many years.  So I have to try the fast version.  I have some linseed oil that has been in a pan for about one and a half years since the Summer of 2021.   It is now a dark orange very sticky substance so I can see how it is changing over time.   

I was able to get some of it to dissolve in an alkali water solution and then precipitated it and it was alcohol soluble but there was some undissolved residue in the bottom of the jar.   

My Linoxin is completely soluble, so I assume your residue is due to insufficiently polymerized/oxidized parts. But I wouldn't worry about it, I would simply eliminate them by filtering with filter paper once dissolved in alcohol. Do this before adding the linoxin to the varnish so that by weighing the dried residue you can figure out the actual amount of linoxin that will be in the varnish.

It would be interesting to see if this alcohol-insoluble residue was also insoluble in the alkaline solution, which I believe is probable. You should try to filter the linoxin when it is dissolved in the alkaline solution to understand this.

But in any case, if the insoluble residue is minimal, I wouldn't worry so much about it.

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It really blows my mind to think you've been making violins since before I was born. I see your fantastic videos and get a little sad that I'm not that amazing at this, but then moments like this remind me that the time and work you've put into this is much greater than I have. In 1986 I wasn't even a twinkle in my parents eyes yet. 

Realizations like this help calm me and put me back into the groove of steady progress over the years. 

You've made contributions to violin making that no generation has ever had access to in the process over the years. Hats off!

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3 hours ago, Nick Allen said:

It really blows my mind to think you've been making violins since before I was born. I see your fantastic videos and get a little sad that I'm not that amazing at this, but then moments like this remind me that the time and work you've put into this is much greater than I have. In 1986 I wasn't even a twinkle in my parents eyes yet. 

Realizations like this help calm me and put me back into the groove of steady progress over the years. 

You've made contributions to violin making that no generation has ever had access to in the process over the years. Hats off!

Thanks Nick.

Maybe it's because I suffered a lot from the closing attitude of luthiers (secret!) when I was a beginner. But in the end this was also good, because it pushed me to research as much as possible to discover things for myself, and perhaps given the lack of knowledge of the luthiers of the time (I started school in 1978 at the age of 14) saved me from following wrong advices...:lol:

I do not deny that sometimes I fear that giving too much information can make you lazy and not stimulate personal initiative, but deep down I am also convinced that even with all the information in the world, nothing can be done without a very deep personal dedication, which remains the first and most important thing to be successful in violin making.

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On 11/19/2022 at 10:36 AM, Toby34 said:

Hi Davide,  love your hand stiched fine rasp for neck outlines, mine is too coarse.  May I know where you bought your fine rasp please?

many thanks - your vids are one of my main my reference sources!  

I got mine many years ago here in Cremona, it's a cut 5 rasp handmade in Hungary. I think it's the same craftsman who makes these: https://www.liuteriashop.com/it/attrezzatura/raspe/raspa-piatta-b-b-mm-200

It looks very similar, but it's best if you ask if they are still the Hungarian handmade ones.

Recently a very kind "fan" of my videos sent me one of these as a gift:):https://www.cremonatools.com/special-rasp-neck-mortice-cut-7.html

I haven't tried it yet for the neck specifically, but it works quite well, even if it is a finer cut 7, probably less efficient in the beginning if you have to remove a lot of wood. There is also the cut 5 but I have not had the opportunity to try it.

Otherwise you can always ask Pechar Rasps, he works very well as far as I know:

https://pechar-rasps.com/en/

 

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On 11/27/2022 at 4:28 PM, Christian Pedersen said:

Maesto Sora, I would enjoy seeing some current images of your older work. So nice to see what something looks like with a decade or two of use.

--Chris 

I don't have many images of the wear after years, I don't bother documenting it. Basically it is limited to chipping on the edges (accidental hits) and wear of the varnish as it would be expected in the contact areas of the hand (edge and rib) and of the neck (lower rib near chinrest). Luckily I have customers who take care of their instruments and use shoulder rests, so wear on the plates is very limited or non existent. Only once did I see on a 1982 violin that the varnish adjacent to the chin rest was almost completely gone, because the player has a thick beard. I usually don't mask the wear. but in this case I had to apply a few coats of varnish to the area to protect the exposed wood. I touch up the chipping on the edges (whitish wood exposed), but trying not to totally mask it but to leave a minimum of relief perceptible. It's part of the life of the instruments.

Just a couple of not too old examples:

2011 violin - Germany - Professional orchestra player

179338984_DavideSora2011IMG_0339ridps.thumb.jpg.f3f8004c818e8bee7c1cfd5525312647.jpg

 

2015 Viola - Spain - Professional orchestra player

386422838_DSC_0099ridmcViola2015.thumb.jpg.8ea31186e3efbbb44002f8c902c4e3b6.jpg

214629559_DSC_0096ridmcViola2015.thumb.jpg.ebe04551d96ff166909d3c3029c4fa06.jpg

 

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