Davide Sora

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About Davide Sora

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  • Birthday 01/07/1964

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    Cremona, Italy
  • Interests
    Violin making

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  1. Davide Sora


    I have never tried, but I would be worried about ruining the sharpening of my tools due to the pumice abrasiveness. Is it not so?
  2. Me too. I use it dissolved in turpentine essence together with other resins as ground sealer coat. it dissolves well in the essence of turpentine, but perhaps there may be a limit related to the quantity. I really don't know and I'm just speculating, however I didn't have any particular problems.
  3. I also keep glue in the refrigerator after it has been dissolved the first time, it works really well.
  4. With synthetic glues my main concern would be the excessive waterproofing effect that could reveal itself just when the ground or the varnish is applied...too late In addition to eternal damnation for the betrayal of traditions, of course...
  5. I am one of those who use the glue re-heated at least once or more for purflings, but more than for a precise choice, to avoid wasting it (I would not use it for structural gluings anymore). I also use it at 70°/72° to slow down the gel time. But I think the most important thing is to know the expansion of your materials when glued and understand how much to make the channel wider than the purflings. I use poplar for white and pear for black, which ensure a good swelling (especially poplar) and I need a channel a tenth wider than the purfling to get perfect seams without to much pressure on the sides of the channel. My purflings go in and out of the channel very easily just using the fingers, without giving any sensation of resistance (if pulled in and out gently and correctly). I also use a lot of glue passed over the purfling as well as the glue in the channel, and despite I inlay the purfling with the fluting channel already made I have never had problems from excessive absorption.
  6. I think the difference lies in the acidity of the resin, as that of Fulton should be neutral (something similar to larch resin), while the cooked rosin may be slightly acidic. Perhaps cooking reduces acidity, but it is difficult to know how much. It should be measured every time with a laboratory test, hardly anyone does (probably no one). Neutral resins should not give problems of craquelures because they are more stable, while acidic resins could give. I made Fulton resin without any exothermic reaction problem, but my turpentine had oxidized naturally in about 20 years, I don't think there was any trace of peroxides left. But I did not make a varnish with it, I used it in percentages in the ground together with other rosin. It seems to me that it has a really nice refraction on the wood, I would have been sorry not to use it in some way, after all those nasty fumes.
  7. I didn't know you were a Dungeon & Dragons fan
  8. Davide Sora


    And use epoxy to fill the gaps... I'm just kidding, many don't use chalk to adapt the bassbar, it can be done. But I feel more comfortable using it and I think it speeds up the fitting.
  9. You need a very light accelerometer for that kind of measurements, perhaps more than one, I don't think you can make reliable measurements with something cheap, and I'm not even sure that it's possible to make them reliably in any case. What would you like to get from these measurements?
  10. Davide Sora


    Red chalk is another option for better mark visibility. I do not like colored chalks because they make a mess when the fine dust penetrate the wood and it is quite impossible to avoid it completely as far as I am concerned, but I have not studied the problem much as I am very comfortable with the white one of which I have a supply that I think will last me forever and I will pass on to posterity
  11. Davide Sora


    The good old blackboard chalk works perfectly for fitting the bassbar, that's what I use.
  12. I would say that straighter would be less stiff transversally, but stiffer longitudinally. But as Don Noon would say, the situation is more complex, it is difficult to separate things analytically, and this is probably an oversimplification. Tonal consequences? It depends on how these stiffnesses combine with everything else, even more complex...
  13. It seems to me that the higher level curves are too angled when they cross the central fifth between the C. I would prefer a more straight course, a bit more as seen in this image (not my arching, just a picture found on the web to give an idea, I don't know what the numbers mean) :
  14. You can always ask at the Academia Cremonensis, they also do personalized courses I think