Uncle Bob

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  1. Uncle Bob

    Stradivari's secret was a concept?

    It is clear that Antonio was a craftsman who stayed busy and had a high standard for productivity and quality. I think he quickly rejected things that did not give him good results. Working wood by hand in a shop with other workers, give you time to talk and time to reflect. Put yourself in Antonio's shoes for a moment. Consider what a great craftsman who knows, sound, materials, tools, craftsmanship and art, thinks about. Consider the craftsmen you know that come close to being as good or better than Antonio was. Think about what they have in common. What they have in common, they have in common with Antonio. Did he examine and go out of his way to figure out how others got their results? Did he listen to others and try to learn, test and expand on everything they knew? Of course he did. Did he have things he stuck to that no one could possibly talk him out of? Of course he did. Innovation, material science, alchemy, math, magic and philosophy have been part of luthery since strings were stretched and played. The violin may have been fairly recent, but he was taught by the best and the previous forms and variations were there for Antonio to study. I am sure that he knew the relevant alchemical theory. I am also sure that he put practical and reproducible results first. The clearest line between Alchemy and Science is the ability to reproduce results. Many alchemists were scientific and many scientists practiced alchemy. In Antonio's case, he was probably informed by the doctrine of signatures, but it never got in the way of his doing what he had tried and tested. He may have waited for the right phase of the moon to make pegs, but I doubt it ever got in the way of his putting together an instrument.
  2. Uncle Bob

    Stradivari's secret was a concept?

    Marin Mersenne, 8 September 1588 – 1 September 1648, had already written Harmonie universelle. In those 800 pages, apart from watching sawdust dance on wood and using Audacity to compare waves, just about every bit of physics that you can use in your modern workshop was available for a smart and skilled luthier. All Antonio had to do was walk to the naval yards, take a small measured sample of wood from each of the huge trunks lying there and measure the speed of sound in the wood by listening to the pitch. With a few days effort he could have more of the best wood than he could use in his lifetime. Add an amazing ear and great craftsmanship and you have your answer to the secret.
  3. Uncle Bob

    Merry Christmas

    Merry Xmas!
  4. Uncle Bob

    woodworm - how can I be sure it's inactive?

    Definitely go the full time on gas processing. When I was doing repairs in a lab, I had a cockroach in a vacuum system for eight hours. I didn't get it much past 10^-3 tor because the insect was out-gassing. When a professor came in and saw that I had the vaccum system working he told me to clear it because he needed to use it. I said, "It hasn't worked for three years and I am still testing to see if it stays stable. He said "You are torturing a bug. I have a use for it that will do for the test." The cockroach showed no signs of having been damaged from it's ordeal up until the moment the professor squashed it.
  5. Uncle Bob

    Flood Damaged/Moldy Instruments

    +1 on the vinegar advice. Vinegar is a great mold killer, and apart from compounds made in reaction to it, vinegar evaporates entirely. You have to be a lot more careful with bleach. I am not sure I would use hydrogen peroxide but I would use dilute hydrogen peroxide in preference to bleach.
  6. For one thing the acoustics are not what you typically face. For another, salt water. Nuno Santos Surfing with a Violin
  7. Uncle Bob

    The Purpose of Ground?

    The method I like uses milk paint. The bottom layer is low PH to dissolve the casein. Lime and/or Borax work well for that. The theory is that treated leather is acid and the base will join to it better. (Alchemists thought so at the very least) The top layer is acidic and has oil in it. When the bottom layer is nearly dry, the top layer is added. When casein is combined in and acid and a base layer with oil present, the casein will cross link and make a very tough substance that remains flexible. This recipe works well on a lot of woods. I think it looks horrid on cedar though.
  8. Uncle Bob

    The Purpose of Ground?

    Gladly. One example would be the classic violin finish with a ground. Most grounds are white in tone. After the ground is on the violin is usually a flat dusty sort of white shade and does not look all that great. Before the varnish is added the ground appears opaque and lets very little of the wood's character through. The varnish used is usually quite dark when you look at it in a bottle. After it goes on, it is thinner so it is more transparent than dark. When you add the varnish, a lot of the ground tends to disappear. There is still a light and reflective coating though it is not as evident. The varnish is more refractive than reflective. The effect is that the light comes back from the wood and has a feeling of depth as it is glimpsed through the darker and richer varnish layer. This method is used by painters. Gesso in the background and a lake on the surface gives a feeling of depth. I first learned this method while studying old methods of treating leather.
  9. Uncle Bob

    The Purpose of Ground?

    As far as I can tell, there are several reasons for a ground but only a few good ones. Preservation, sound, appearance and strength are the only good reasons I can come up with. Two of the bad reasons, mystique and marketing may win over the good ones. Preservation: Putting something like borax on the instrument may help. Sound: Preventing the pores of the wood from filling could make for a better sound. It is possible that some ingredient such as borax might make the transfer of sound from wood to air, work better. Since the ground is covered, this would be more likely with a distressed finish than a polished one. Appearance: The classic way to give an illusion of depth to a finish in wood or leather is to first coat with a bright or even somewhat white layer and then cover that with a transparent but darker layer. The materials used in most grounds would seem to support this as a motive. Strength: There are formulas that are said to strengthen wood. The formulas I have seen thus far don't look like things I would do to a violin. If the formula worked and continue working over time, it would still probably lower the speed of sound by adding mass.
  10. Uncle Bob

    Colophony shelf life

    Apart from having the secret to immortality, you would have extremely low and slow cooked colophony.
  11. Uncle Bob

    What kind of wood is this

    I think it is ash, but it could be oak. I would need to see cleanly cut end grain, that has been blown out to remove dust, to be more certain. Ash would be more evenly grained. White oak would have groups of pores that are filled. Red oak would have groups of open pores. Most folk go by color but then most folk think a drying oil is an oil that damages your skin. As far as hardness goes, this is only a vague help. Ash is normally between red and white oak for hardness, but it can vary hardness quite a bit.The hardest ash I have worked was harder than any oak that I have worked. Oak is weird too, it crossbreeds freely and a lot of woods will have ten or so varieties mixed in. We say red and white and think that defines oak, but there are huge variations in Quercus. We typically identify an oak by it's leaves when living and by it's wood when dead. Even the range of qualities that identify red and white are not always clear. My general guess is that it is ash and not hickory. I would not bet any money on my guess though. The scent could have been caused by treatment with turpentine, so again, this is not enough data. Appearance of resin might give a bit more data.
  12. Uncle Bob

    Pseudonyms

    Shortly after my joining there was an event where a few members of Maestronet were being attacked. I took the opportunity to change my identification and conceal my identity. Luthery is a hobby to me, my reputation in the field is unimportant. My ear is good, better than most, but not good enough for me to ever become a great maker. I have good relative pitch and my ear does not lie to me as much as it does to most. Sadly, my ear it is not golden. Sadly an ear good enough to be a great maker is a rare thing. I should probably switch to making banjos. I enjoy sharing my thoughts, but my thoughts should be respected or despised on their own merit or lack of merit. Out of respect for the amazing members of this forum, I try to give my best observations. I would rather that my good ideas spread and outlive me, than have my name remembered. Anything that I say that is true, is simply a reflection of the universe and I cannot claim to own. Anything I say that is false is sadly mine. For me, there is no advantage to use my name and tell who I am. In general though, I respect those on the forums who identify themselves, more than the cowards that make up the group I belong to.
  13. Uncle Bob

    Wood swimming

    Show this to anyone that says that end grain isn't pretty. Then show it to anyone who says you can't put a nice surface on end grain. Thank you for sharing!
  14. Uncle Bob

    The current "Golden Age" of making

    Thank you. I love it when someone explains something I have noticed but not really understood.
  15. Uncle Bob

    The current "Golden Age" of making

    While disagreeing with you, I agree with all of your points. Sound is subjective and if a craftsman is good enough to aim and get the sound he is looking for, he will be able to make an instrument that probably sounds (to his ear) better than an instrument made by Antonio. A good luthier may have good reason to think that his instruments are the best made. I might not agree, but I don't buy a lot of instruments. The sacrifice of structure for sound is another big question and while I personally think we should aim for making instruments that will hold up to the test of time, that may not be as important a criteria to some musicians. Mandolin players for example are not giving up their mandolins. Mandolins have so much string tension, that their potential lifespan is substantially shorter than most violins. As we sacrifice one quality for another, and look for something to give so we can tweak an instrument a bit more, lifespan may be one of the easiest things to sacrifice. The charismatic personalities with their odd ideas make us question ourselves. They make us look and test things that we might ignore otherwise. I think these folk add something, even after we decide that sticking a plate in a violin or shaping ribs oddly or smearing something different on carefully damaged wood is not really helping us. I personally think that the first part of the quest for making a better violin is to become an outstanding woodworker and an outstanding designer. We have quite a few of those around. That combined with the sharing of data that we have happening today, in my opinion, makes this a golden age.