Davide Sora

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About Davide Sora

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    Enthusiast
  • Birthday 01/07/1964

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    http://www.davidesora.it

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  • Gender
    Male
  • Location
    Cremona, Italy
  • Interests
    Violin making

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  1. Davide Sora

    Sound hole edge finish

    For pegbox I use the same varnish than the rest of the violin, just a little darker to have some contrast. For F holes acrylic black paint (opaque), the same that I use for scroll chamfers : https://www.amazon.it/Maimeri-m1220530-Vernice-acrilica-Black/dp/B00A6WN310/ref=asc_df_B00A6WN310/?tag=googshopit-21&linkCode=df0&hvadid=90702391980&hvpos=1o2&hvnetw=g&hvrand=15472415599517055321&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=1008267&hvtargid=pla-465954614293&psc=1
  2. Davide Sora

    Mixed varnishes with shellac (spirits)

    The best alcohol is food grade ethyl (Everclear), what you use I think is good, what I use is isopropyl alcohol, which costs less and work fine (but you can't drink it....). Raw shellac (seedlac) in dry state last forever, at least my thirty year old raw shellac still dissolves perfectly. All other types of shellac may have received treatments that affect the durability (and quality), for example the bleached one becomes insoluble at some point, good reasons to prefer raw seedlac. Instead, when dissolved in alcohol, any shellac has a limited life because it triggers an esterification process that turns it into a rubbery material that will never harden. A shelf life of six months is appropriate, I consider one year at most but the varnish will be proportionally more elastic. Make small batches at time and use fresh is a good thing. Cooking time is not crucial for alcohol varnishes and there is not much choice on the ideal temperature as it is inevitably established by the boiling point of alcohol, slightly raised by the presence of resins (my alcohol varnish boil around 80°/82°C). Simply do not let it boil too vigorously, but it is only common sense, always beware alcohol vapors. Regarding the recipe I think the simplest and most effective is the 1704 Seedlac varnish, similar in concept to that of Nathan but with a smaller number of resins used.
  3. Davide Sora

    Why arching shape?

    I agree that in a simplified model a longitudinally less pronounced arching resists compression better, but this depends on the shape of the long arch and if the curves are concentrated in one point near the blocks or more evenly distributed. I am led to think that this thesis is better applied dividing the arch in two portions from the bridge to the block, where a too curved line is very deformable while a more straight line reacts better to compression. Considering this the arching height is less important (within certain limits) and as a perfectly triangular line would bend inwards there is a need for a slight arch to compensate for the deflection. Probably a finite element analysis could shed light on this aspect and make it possible to calculate appropriate curvatures, but in the meantime someone takes the trouble to do so we can only appeal to our experience and "intuition" hoping to get it right.
  4. Davide Sora

    Do you make your own varnish or purchase from a vendor?

    Clearly there is no evidence at all, also because we know something about the materials but we do not know how the varnish was made. Hot cooking? Cold mix? Solvent or not? Evidence? If Stradivari had been an Alchemist (rather fashionable in those days ...) he would have surely made it's own varnish in the search of gold.... I do not think it was, but there is no evidence of this either.
  5. Davide Sora

    Do you make your own varnish or purchase from a vendor?

    I make my own. I have nothing with those who buy already made varnishes, but surely I bring much more respect for those who make their own varnishes by themselves. I think that the understanding of the materials obtained in this way is unequaled, buying them already made saves time but we lose a lot of knowledge (and fun).
  6. Davide Sora

    RIP Maestro Francesco Bissolotti.

    I remember his significant presence at the school in antagonism with Morassi, the other leading figure of the time, who also passed away last year. With their passing definitively closes an era for Cremonese violin making, I hope that the students will be able to overcome the masters. I had met "Bisso" just in September, my last goodbye. RIP
  7. Davide Sora

    Swedish scroll gouge set

    Most likely, but having no interest in making copies my priorities are not exactly to equal Testore in terms of workmanship quality. Someone could scream heresy, but I think that the tools we decide to use will influence the style of our work and everyone can make the choices that he thinks most appropriate, I do not see it as a challenge of skill to be able to use as few tools as possible.
  8. Davide Sora

    The importance of varnish

    I have all respect for Greiner as a violin maker, what I meant to say is that he is not a scientist but just a maker and is not bound in his statements to scientific rigor as instead Brandmair must be.
  9. Davide Sora

    The importance of varnish

    Brandmair does, Greiner is just a violin maker....
  10. Davide Sora

    Swedish scroll gouge set

    Good luck!!!
  11. Davide Sora

    Swedish scroll gouge set

    Unfortunately I do not know a better system to establish the accurate radius of a gouge if not drawing a circle and physically overlapping the gouge, but to do this you should have already bought it or at least go to the store to be able to examine it. In this case you will have to endure the glances of the employees who will look at you like a strange person....
  12. Davide Sora

    The importance of varnish

    There are good chances that at the time of Stradivari the winters here in Cremona were more similar to those of your home, given the problem of global warming As for the book by Brandmair and Grainer I think it's worth the price only for the fantastic photographs and astonishing macro details it contains, the rest is certainly interesting but surely interpretable and not conclusive, admitted that this will never be possible, in any case the best physical description of the Cremonese varnish I have ever read. The high cost I think is given more than anything else by the quality of the photos, like all other books on violins with high quality real size pictures.
  13. Davide Sora

    Thought you might like this article

    In the article have certainly exaggerated, but I must say that it is true that the noise of traffic, especially the accelerations of the engines of cars and motorcycles is perfectly audible inside the auditorium (I can confirm this by direct experience), a serious and annoing problem that forces to close the surrounding streets to vehicular traffic also during the concerts. People like Maxim Vengerov or Shlomo Mintz do not take it well if they get bothered by the clatter of a scooter in some very expressive pianissimo.....