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About Mike_Danielson

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  • Birthday 10/22/42

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    Materials scientist--PhD

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  1. Recommendations for replacement frog

    I cannot figure out what quality level this bow might be from the description. $1500-200 seems very high for a hand-made frog. Since this is a new frog to an old bow, there will be a future problem with recapturing your cost since the bow will be considered in the collector market as a composite. Perhaps you should think of it it terms of being a "players bow." Howard Core is selling silver-mounted ebony violin frogs with Paris eye for as low as $200, list. With any modification like this, the pro should do it to maintain such things as weight and balance point. Mike D
  2. Thinning varnish

    You are making this too hard. Just add turpentine to the varnish and give it some time to dissolve--maybe 12 hours. Stir, check the viscosity and see if you need to add more. If the varnish is healthy, there is no need to reheat to incorporate the solvent. Check for lumps; perhaps filter. Do not add more linseed oil unless you want to change the resin/oil ratio, which I think would be a mistake unless you recook it. Do not rush this incorporation of the solvent--give it some time. There is a big difference (chemical composition) between mineral spirits and turpentine. Use turpentine. I do not see how heating on a water bath can have much on an effect on the varnish because the temperature is so low. The dangers associated are very small if you do it outside and use an electric source for heat. Let's be reasonable and low intensity about this. You can incorporate the solvent, faster, if you heat the varnish, but if you have any worries, do what I said above. Mike D
  3. Tax proposals

    It is way premature to try and outguess our congressional leaders on the new tax laws. So, do not panic yet; there is plenty of time for that later, if they really do something. My surmise is that nothing will get done this calendar year, and maybe for the entire presidency. I do like the idea of a Schedule F. I edited this to add a Mark Twain quotation: "There is no distinctly American criminal class--except Congress." Mike D
  4. Cracks in Bending Ribs

    The only think I would add is to soak the wood in water for a longer time. That is, do a soak if you are presently doing a quick, surface wet to the wood before going to the bending iron. Say 20 minute soak. Sometimes a longer soak helps with difficult wood. Mike D
  5. Beady eyes... extreme version of fisheye

    Let's think the unthinkable--the mystery solvent is contaminated with something, maybe silicone. If this happens again, use a coat of shellac to restore bite. This is my secret, but I am going to reveal it to all. I never could keep a secret. Mike D
  6. Downforce Experiment

    Just a quick reminder--you can calculate the downward force very easily knowing the string tension and the string angle relative to the bridge. It is a cosine function. Is the break angle important, the OP says it is not very important, and he ran a test rather than doing the hand waving. Mike D
  7. Rust inhibitor/prevention suggestions

    VCI paper--here is an example of what I am suggesting. https://www.amazon.com/Daubert-Cromwell-UW35MPI36x100-Corrosion-Inhibitor/dp/B00ANUNWTI Mike D
  8. Everclear alcohol

    Everclear is all I use. $16 In Oregon liquor stores for a 750 ml bottle of 190 proof (95%). Much lower water content that the stuff you buy at the hardware store. Mike D
  9. Sharpening Bridge Knives

    Bill, I am going to take your comment seriously. I would start with cold water containing a special detergent. Spartan makes a special enzyme laundry detergent that is especially useful for removing blood. You will have to make multiple applications and give it a day or so. Keeping it damp would be useful. You should be able to tease it out. This stuff worked for me when my cat left me a bloody, dead mouse on a wool carpet. I did not notice it for a week until it stunk. The Spartan product did a perfect removal. That gallon of Spartan cost about $50. Mike D
  10. Sharpening Bridge Knives

    $1200 for a Tormek grinding system--have you lost your minds? Have you forgotten what Michael Darnton was talking about a few years ago using a hand grinder? Here is a link: https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&ved=0ahUKEwj-6LGJzsHVAhXEy4MKHfznCqsQFggoMAA&url=http%3A%2F%2Fwww.darntonviolins.com%2Fviolinmagazine%2Fbook%2Ftools%20and%20sharpening.pdf&usg=AFQjCNE6SnaR5Cqh2IoMqPE3ZSfv6rlS1A The beauty of a hand grinder is that it is inexpensive and grinds slow enough that you do not overheat the steel. A few years ago, Delta made a system somewhat similar to the Tormek. You should be able to pick up for little money. Throw out the big grinding wheel and replace with a new one from McMaster-Carr. Mike D
  11. Sharpening Bridge Knives

    Brad gave some very good advice on sharpening these knives--it is so much easier if the blade can be removed from the handle. With the handle in place, the knives wobble on the holding platform. If you try to do it free-hand, you lose accuracy in controlling the shape. You really want a slight convex blade shape but that can easily come from the final sharpening on the wet-stone since stones are usually cupped. Mike D
  12. Japanese paper (washi)

    When I say I suspect something, it means that I do not have any data. Do not forget that cloth is filled with empty space because the threads are not tightly packed together while the wood fibers in paper are tightly pressed. This is probably where the strength of paper comes from. Now here is something you are going to need to think about: when you put one side of a thin piece of wood in compression, the transmitted forces cause a tensile stress on the other side--is this something you want? I would prefer something that is neutral. When we say silk is stronger than steel, it means strength per unit of density or weight. For instance, compare a bar of steel with a similar bar of silk--which would be stronger? You can see that on the basis of similar shape, the steel is stronger. I use hide glue to put the washi paper into place, and I put it on both sides of the paper. Mike D
  13. Japanese paper (washi)

    I use washi paper to reinforce vulnerable places on the cello sides, and I recommended it to others in a post a few months ago. No response to my comment. Any place where the side flattens out is vulnerable to cracking from an outside blow, and that is where I place several layers of the glue-saturated paper. I suspect it is stronger and lighter than fabric. I don't know about the density of the paper I use, but you can easily apply multiple layers. My stuff is pretty thin, and I used 3 layers. Let is dry and see if you like the improvement in strength--you can always add more layers. Mike D
  14. Varnish, quick and dirty.

    If you can make marinara sauce for your pasta, you can make varnish. Follow Hargrave's recipe. If you want to save time, add the rosin and oil at the same time and then heat it up. Plan on going near 300 C which is different from what Hargrave did. You should be able to get the right color within an hour or so; that why you want to reach a high temperature (see the Peter K-G photo). Don't worry about getting the long strings--it will take care of itself. Add turpentine after it has cooled to a safe temperature that you can add a volatile liquid. Add line or leave it out--this process is simple enough that you can easily make multiple batches as an experiment. You will know what is in your own varnish since you put it there. regards Mike D
  15. Pseudonyms

    It all gets down to credibility. Anonymous sources have no credibility. If I was the monitor of this site, there would be no anonymous members allowed to post. Mike D