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About Mike_Danielson

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  • Birthday 10/22/1942

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    Materials scientist--PhD

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  1. Mike_Danielson

    Odd Cracked Pegbox Repair - Recommendations?

    I would not do the CF repair. Ream out the hole and bush with either a kraft paper bushing or wood bushing, depending on much the hole needs to be reduced in diameter. Then use the smallest diameter planetary peg (mechanical peg) for that location. Maybe do all 4 pegs. The bushing will give the repair enough strength since the mechanical pegs do not jam into the hole very hard. Mike D
  2. Mike_Danielson

    Why does my wolf note move?

    The cello wolf is a popular subject on this site. G is an unfortunate wolf because of the open string and harmonics. You can make a capo with a piece of string tied around the neck. Bow the note and feel the top with the left hand. You will find it located (usually) below the f-hole (bassbar side). You can shift the note by using a wolf eliminator that is attached to the afterlength. It would not hurt to have a luthier take a look at it. Changing the afterlength will probably have an effect. Soundpost less so. String change will shift it. Mike D
  3. Mike_Danielson

    Vernice bianca vs plaster ground

    Just a thought: if you want to keep future woodworm or other bugs away, do not put food on the wood. Mike D
  4. Mike_Danielson

    Lake, Rosinate, lightfast?

    If you want historic recipes, then read the work of Mrs. Merrifield. The recipes leave a lot unsaid but their simplicity should be listened to. Roger Hargraves's work is very similar to what Mrs. Merrifield reported, he just needed to use a higher temperature to develop the color, faster. It has to be simple or they could not have done it 300 years ago. Do not screw it up. Mike D
  5. Mike_Danielson

    The ground ( sealing) of the great masters - which was it ?

    Danube fiddler--most of your questions will be answered if you read Bruce Tai's Review of Stradivari's Varnish. I am surprised that no one mentioned it. Be more suspicious of G/B's book and Echard. A great problem of G/B's book is to suggest the idea that the initial varnish is a very lean oil varnish. Read Nagyvary's comments--he is the guy that would know the reliability of the analytical method that leads to this conclusion--and he is suspicious of this conclusion. Your guiding rule should be simplicity. If is complicated, they did not do it. Mike D
  6. Mike_Danielson

    Varnish melting point and repair options

    This is too bad. Pictures would help. Here are several suggestions: 1. Take it to a luthier who will strip and revarnish. 2. Take fittings off and use spray paint to paint it blue. Put stuff back on and play. 3. Do nothing. It becomes a conversation point. Mike D
  7. Mike_Danielson

    The ground ( sealing) of the great masters - which was it ?

    For those that cannot see the advertisement, I pasted a page from a 1900 Strad magazine. It was an Ad for Whitelaw's amber oil varnish that promised that it was "identical to the best Cremona varnishes." I had no idea that there would be a problem that would prevent some people from seeing the ad. The New York Public Library had copied all these old Strads (which are available on-line), and I made a copy of the Ad and pasted it into Maestronet from a Pdf file. Anyway, you can see that the varnish issue has never gone away. There has been plenty of pontification over this issue in the last 118 years. Mike D
  8. Mike_Danielson

    The ground ( sealing) of the great masters - which was it ?

    This might be of interest from a 1900 Strad magazine. Wonder how that Whitlaw varnish worked out over time--but it is the finest varnish in the world. I bet there is a lesson in this. Mike D
  9. Mike_Danielson

    High resin content varnish

    Michael, how do we know that two different varnishes were used? Is there any data in the literature that points this out? Isn't it possible that just one varnish was used, with and without coloring stuff added. Nagyvary says that it is likely that the famous instruments have been french polished many times (over 20 in his quote). That would insure that the outer coat would be a clear, low color of shellac. But depending upon how much alcohol was used and the propensity for the oil varnishes to dissolve in alcohol, the outer layers could be a blend of original oil varnish and shellac. Mike D
  10. Mike_Danielson

    High resin content varnish

    The only decent review of the Brandmair & Greiner (in a scientific sense) was carried out by Nagyvary. And he was very skeptical about the "lean" oil varnish that the authors discovered--saying that the FTIR method was not capable of making this analysis, accurately. With that in mind, I would not put any effort into this lean varnish idea. Rather, I would fall back on the idea of "keeping it simple." That is, the masters used one varnish for the entire work, but they probably added stuff to it (coloring agents) to get the right color or thin layers that were incorporated into the varnish. Nagyvary also mentions that there is a lot of particulates or solids in the varnish (10% in some of the violins)--that sounds like a lot to me. They could have been put into the varnish or directly applied to the varnish coat with a thin coat applied over it--this latter suggestion repeated again and again. I would err on the side of simplicity. Mike D
  11. Mike_Danielson

    Bench lights

    But it directs to another model with the same 45 " arm length. A call to McMaster-Carr might be necessary. This arm length is very useful Mike D
  12. Mike_Danielson

    loss of value in bow after spline

    Edi, does the width of the spline scale with the strength? In other words, if the spline was 1 mm wide would it have 1/2 the strength of a 2 mm wide spline? Edi is correct that there would be a neutral axis when the stress goes from tensile to compressive as you would move away from the tip. The force of the tightened hair is the driving force for this behavior. It would make sense to use less hair in a compromised bow in order to lessen the tensile stress. I think applying fracture mechanics to the problem would also be useful. It is important to prevent a starter crack (notch) from ever forming. The spline sits at just the place you need (maximum stress point of the tip) to prevent that notch from forming. The problem with just a glue repair is if the glue yields at the point of maximum stress, the starter notch will form, and would eventually lead to failure (crack growth and the original glue joint fails). Mike D
  13. Mike_Danielson

    Bench lights

    https://www.mcmaster.com/#1523k22/=1cp27zy This is the one you should replace the Luxo with--it has a 45 inch long swing arm--takes regular light bulbs. $135. I have two of them Mike D
  14. Mike_Danielson

    Pegbox crack

    Let me make different suggestion--use a planetary gear peg since they do not have to be jammed into the pegbox. First glue the crack closed, then ream out hole and insert brown paper spiral bushing, and then ream back to where the gear peg will gently fit. Mike D
  15. Mike_Danielson

    loss of value in bow after spline

    Several years ago, I saw a broken Hill cello bow (silver plate on the tip) for sale on ebay. I cannot remember if it was stamped W.E Hill & Sons or one level below that. It had been repaired with a fairly wide spline (not certain if it was pernambucco), but it had broken a second time through the spline, and it was offered in this broken condition. The spline did not hold the original fracture, closed. I bid on it but lost because it went for about $450, well above what I was willing to pay--I was willing to go to $150. I wanted that bow to see if I could determine why the earlier repair failed--obviously, I thought I could fix it. Was failure due to the use of hide glue rather than new glues? Was it a pernambuco spline which is more difficult to make a good glue joint over say maple or cherry wood splines? The grain of the spline was inserted at the 45 degree angle. I lost track of that bow. There was an opportunity to learn something from this failure. Anyone know if it was repaired? Mike D