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Greg Sigworth

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Everything posted by Greg Sigworth

  1. Thanks for explaining this, I would have thought sawdust was OK.
  2. I was going to say I had two and then ask if that counted, but before I could IMHO piped up and said to have five including a bull. How can I compete with that. I guess I should be glad Saradivari at least used letters. What would we be saying if he just identified it as #2?
  3. An additional thought: shock loading can also cause a stress raiser to become active and cause a crack. Also, Is there a possibility the crack was there before you worked on the plate but not seen. Being able to put the sap pockets cracks in the F holes was really creative!
  4. Just a question. The ends of the sap pockets appear to have acted as a stress raiser resulting in the cracks. Was there any stress put on the plate when gluing the two halves which provided the stress for the cracks to progress? Did you clamp the two halves together to eliminate a gap in the middle region of the glued seam? This would have put the f hole regions in tension in a longitudinal direction after the clamps were removed.
  5. I bought in to Hutchins tap tone ideas and the octave separation on the 1st, 2nd and 5th eigenmodes for the unassembled plates. She suggested using tuning varnish applied to the plates and then being removed before assembly. A lot of extra work. For my first five violins I actually varnished the plates and fully tested and graduated them, then assembled the body and varnished the rest of the violin. For me now the eigenmode patterns are of value only showing me that my graduations are close to where they should be. If the shape is off I need to fix something. But the frequency value is only of value for future reference. I kept records of frequencies on all plates in the white and then after each coat applied. As a general rule the frequencies went up, the varnish added stiffness to the plates. I used fulton varnish and a UV light chamber and this was applies after a sealer applied, sometimes just egg white. To predict the frequency effect of varnish there are too many variables such as the ground and sealer used, what kind of varnish, how it is applied etc. I keep record of eigenmode frequencies and patterns, but there real value is not that of a target but rather that of an indication if I have made some mistake or need to make a correction. I just went back to my notes and checked some of this. I used the same varnish on these violins but the frequency change followed the same pattern in a qualitative sense but could not be exactly predicted. Frequencies on the 2nd and 5th mode generally went up after each coat (up to six coats) with maybe a total increase of five to ten CPS. The effect of varnish seemed to decrease with the later coats applied. I now assemble the violins in the white and varnish after assembly; exception being any work on the inside.
  6. Mozart: Eine Kleine Nacht quartet music and Tchaikovsky Violin Concerto in D: and especially with the second I wonder which would be greater; to be able to play like that (in this case Itzhac Perlman) or to make a violin that would sound that good when played by someone like him. I wish I had more time to grow this list and work on violins.
  7. I worked for and with a master sheet rock finisher for a while. He could apply and shape the surface with his tools and he was done; no sanding necessary. Those who can not do that have to sand and sand till they make a mountain of dust. The tool marks of the masters as Amati testify to the fact that they could shape the surface of the wood perfectly with their knives and gouges, etc. They had no need to do more than that. Their tool marks are a great testimony to their skill. I guess Guarnari was so skilled that he could use gouges to do the edge work on the plates and then be done, with only a few tool marks left to testify to the process and that he did not have to scrape or somehow finish what his hand could not do. The tool marks of these men testify to their skill. That is why they are beautiful.
  8. In the world of metals, protecting the metal from oxygen is done in a number of ways. The temperature is at a lot higher degree than for torrefied wood. Inert gases are not necessary and they are expensive. Nitrogen would work very well. You could first create a vacuum to remove internal oxygen from the wood and then back-fill the chamber with nitrogen and then raise the temperature.
  9. I have wondered why resonance valleys exist. There are very many of them, as many as there are peaks. Could they be (or at least some of them) exactly that, resonance peaks. They are valleys because they are non-sound generating modes of vibration? They are resonance vibrations that generally do not cause plate motion normal to the plane of the plate. They suck up energy but do not produce sound. Well that is an idea as to what they, or some of them, might be. I have read that there are some body mode vibrations that do not produce sound. I believe the A1 air mode is one of these.
  10. Practice using your tools on scrap pieces of wood, but for the violin use wood intended for violins. It works differently under the tools because of the grain orientation and specific types of wood. For the time you will spend the money spent will be very small. My first violin came out quite nice and is still in use. If you succeed you will wish you had used proper wood. The back, neck-scroll, ribs need not to be expensive wood and plain wood may be easier to work with. Get some with a hint of figure in it and you will see the beauty possible. The table or top is more important and could be a better piece of wood, but need not be real expensive. When you finish you will want to hear it! Then the wood (especially the top) becomes very important. Sooner or later you will destroy a piece of wood. If you spend some money you will work more carefully and slower. Resist the temptation to throw it away because you have thought it was ruined. Finish it; you will be amazed how well it turned out. I think I have thought this at least once for every violin I have made; they all turned out quite nice. Only God can made something perfect. And when you are finished you will want to hear it. Then the wood becomes very important. Let us know how it goes.
  11. That often happens when you go down the rabbit hole.
  12. This violin may have a very good sound and you could destroy that fooling around with a new bass bar. I would not gamble on making it sound better. Fix it, put it together and let the owner play it. That bass bar and table have probably had over 100 years to get used to each other. When you get done please let us look at it.
  13. Joining plates is a skill set I am still working on becoming better. But I have decided to "rub" my plates together and then with no clamps or external forces let the seam dry. This has been a bit scary at times but so far works well. Why do this? I have a somewhat unproven idea that violins sound better after they are played because internal stress and strain gets worked out and relax as the violin is played. If this is true why build into the plates the bending strain resulting from clamps forcing two surfaces together? So, I plane the plates as flat as I can and join the two halves without any extra force applied thru clamping. Is this important, does this make sense?
  14. I did not read all the responses, but I tried to do this with shrimp shells in the 80's and the shells were indestructible to a boiling concentrated lye solution. I wrote to Nagyvary about this and in his response he said I was very naive to think that he would easily give out such information. Then I had to find some place to throw away the large bag of shrimp shells I acquired from a restaurant. I haven't pursued this theory since.
  15. I have come across this idea many times when I read anything relating to violins, usually in some pamphlet written claiming to have found the secret to great violins. W. W. Oaks A Review of Ancient and Modern Violin Making is typical. I have no personal experience to prove or disprove. The claim is that violins in the white often have a very good sound which is lost in the finishing process. This may just be one of those ideas that is passed along until it is assumed to be true. Any one have experience in this? If it is true, then what is the acoustic importance of the ground layer? The previous assumption leads to the conclusion that finishes on the violin are harmful to the sound and should limit as much as possible this effect; and it seems to make sense that this is true to some degree. In contrast to this view it seems that the ground may actually improve the sound of the instrument or be very important to it somehow. So, do violins in the white actually have this better sound. Or is this idea just another false idea we consider as true.
  16. I would like to make one violin like this. The reds I use seem to all faint when in the UV box.
  17. I was walking in a mall about 15 years ago with my wife and saw a wheat penny on the floor. When I picked it up it was not in good shape but it was a 1909 VDB S penny. What are the chances of that? Probably best to leave the penny or whatever in the violin.
  18. I would be tempted to take the dime out and see how old it is. The dime might be worth more than the violin!
  19. Beautiful violin. Your varnishing skills are probably a lot more experienced than mine. Having said that, this might help you. In the final step, which is where you are now, if you use pumice and a soft felt cloth you will reach down into the recessed areas and they will have the same patina as the higher areas. Then, you can repeat the process with rottenstone which will give a more polished surface. I use water with the pumice and then with the rottenstone many use oil; I have used water and oil. Sand paper is a flat surface even though it flexes. It will not reach into the lower areas without taking too much off of the higher areas. The pumice/rottenstone with a very clean felt pad reaches both layers without taking too much off of the high areas. Joe Robson has written on this last step in The Best of Trade Secrets #1. He uses a rubbing pad made from an old t-shirt material. I believe he uses a cotton pad dipped in linseed oil for the rottenstone. He then uses a flower dusting to remove excess oil. I would recommend following his process. I am fairly new still in finishing violins and he is way on the other end of the spectrum. Nice violin.
  20. Which gives more structural support to the downward forces of the two bridge feet, the bass bar or the sound post? Is there more support needed under the "e" string or under the "g" string? Maybe there is a structural reason for the current setup.
  21. Thank you: I hope to watch them all. We will see how brave I am.
  22. Thank you for the response. One question, when do you do the purfling, before or after closing the box? Thank you.
  23. The more I think about this, I think one area where I need help is in the transferring of the garland outline unto the plate. How should I mark the plate; with a scribed line or with a pencil? I think my problems may be from not doing this accurately and carefully.
  24. Thank you for the response: Virtually everything I know or am learning about this skill comes from what other makers tell me or write about. I guess I use an open box method. After transferring the garland outline to the plate with the garland still on the mold with an overhang added, using a small washer running along the ribs contacting the plate; then I work the plate down to the line trying not to add because of the line. I glue the back plate first to the garland (now off the mold) trying to make it fit well. I have locating holes and pins in both end blocks and plate to line it up as it was in the mold. Then I loosen a few clamps and glue, then work around doing this. I do the corner blocks first, then C bouts, then end blocks and remaining bouts. It is getting better but still areas of difference in overhang. I do the purfling on the separate plates before joining the box so I do not have any room to reshape the plates. Is there a better way to do this? Thank you.
  25. I was able to easily remove the rib garland from the inside mold with all linings on top and back plates. Hargrave wrote that possibly the mortise of the C bout lining was possibly to give the added strength so this area could be slightly straightened and the garland removed. I followed Johnson, Courtnall's corner block inside corner shape which helps in getting the garland off. The garland came off easily after carefully breaking the corner and end blocks free. Putting all the linings on before mold removal helps me to get a better control on the overhang being uniform. The other holes in the blocks are to put a temporary plate on the garland when off the mold. As I get better at this I may not need this other "crutch". It was really neat to do something that was possibly the way the great Cremona makers did it. This may be well known to modern makers. I hope it also works for this violin as it did for the last one. I still struggle with a uniform overhang in the assembled corpus but it is getting better. Any help in that area would be appreciated.
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