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About Johnmasters

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  • Birthday 05/08/1944

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    Physics of violins
    Finite element analysis for eigenmodes, stresses, whatnot

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  1. The pure oilcolors are too soft to varnish over. There is a danger of a film of varnish coming off and taking half of the oilcolor coat.
  2. Yes, that would favor the low frequencies. I would guess that a stronger bassbar would do help out. Perhaps look inside the endpin hole and see if the bar looks low or too thin. That an perhaps the post is too far back. But that would not be my first guess.
  3. To get into the spirit of copying del Gesu, why not do what he did?? Wouldn't that be to draw some patterns and make a violin carefully as well as you could if you are young ? When you are older and feeling bad or hardup for money, make them more quickly as well as you can, but don't agonize over super-precision. As you speed up your work even faster, perhaps you will get the "spirit" of what del Gesu did later on.
  4. You can use a brush in bowl to make emulsions. What is wanted is a lot of shear involved. Brushes are fine for this, and you can use the same brush and bowel to apply if you want to try brushing emulsiond. I point out once more that you must mix beyond the point of inversion if you want to go from water-in-oil (w/0) to o/w. These are completely different. The emulsion becomes quite thick just before inversion, like a Dairy Queen ice cream.
  5. I have a short 1/2" diameter mill that is a couple inches long. Made of tungsten carbide. It never galls or even gets marks from using as a burnisher. I lubricate with a dry bar of soap, which I think works a little bit better than parrafine. They are not expensive, but not free. Worth a small price for a tool which will last forever. And it has a mirror finish which encourages me that it will make a smooth burr.
  6. Thanks Michael... That seems very possible. Also could be filtering when editing a master recording. Personally, I like things raw and closely mich-ed. "toolmarks for the ear." I did not know that about JB, but I think Julia Fischer has one (or one of the other 'ladies') and I like it just fine.
  7. I have mentioned it before, but it is worth repeating. Scientific American magazine had an article many years ago about a very old trumpet which had been hammered out on a wooden mandrel. It had lots of irregularites and dents. Players found that the tone was "more flexible" then with a modern trumpet. Maybe violin makers try to be too precise (????)
  8. Just as I thought. The lower frequency of roll-off in a much-played violin is due in part from "wearing out" or overplaying a violin. Today, I hear a lot of "viola-like" sound in the lower registers of many players. I don't recall this in old LP's from the 50's and 60's. Do you believe that this has occurred? (the overplaying of the famous old instruments) I have heard that guitars wear out, but I don't know if the players feel this. The telephone was originally intended to roll-off at 8000Hz so that they could stack signals (using hetrodyning) for efficient transmission. This was also the bandwidth for AM radio. (8k either side of the carrier) And I have the old Heifetz "tin-horn" recordings also. The tone is clearly not only easy to hear, it sounds like Heifetz. So all the noise in anything over 9 or 10000Hz is likely to be just noise. My own ears are severly rolled-off over 8000Hz.
  9. I agree with Don. The idea is to remove wood which is not part of the final result.
  10. Hahaha .... all of this objection to "copying. faking, forging, shamming etc is very ironic. Most writers here are concerned to simulate wear, copy toolmarks of old instruments, etc sounds a lot like forgery to me. I simply want to make my own instruments and make them look new. I DO shade varnish a little for interest, not to simulate wear. I wrote a couple of comments about roughing on the "Saving the joints" thread.
  11. Yes, I understood this well. I just took it as an oportunity to add something to the CNC debate. I know there is another thread with a debate. But the main reason I made my CNC WAS to eliminate muscle work. You are faster, of course, because my router cutter moves slowly and I cannot "hog" the wood. But I CAN set up a cut (.1 inch max) and then read the news in another window or brouse the internet. So, eliminating joint stress in roughing DID seem relevant. My attitude toward CNC is not the same as I have read in other threads. I think it is closer to this thread perhaps.
  12. David, I will make a case for CNC. I do not use mine to carve a full plate. It was designed along with my own software to simply make cross-cuts of curtate cycloids. I finish edges seperately and have to light-plane away toolmarks from the CNC cutter. It gives a close roughing which I finish with my hands and other tools. I had found that the purfling channel in maple was really taking a toll on my wrists. I cut this minus the corner miters with a type of pattern-following system rather than a jig-held dremel or similar. The edges and smoothing are done by hand. In other words, people that are unfamiliar with CNC think the idea is to "Do All the Work" miss the point that the best application might be roughing out. It is silly to think that the idea is to make a complete plate, at least in my opinion. And I did not need to make complicated Cad-Cam drawings. For me, the roughing (which could also be done by an apprentice) already can map out an arch and relieve one's joints from much stress. (I am not a body-builder as you seem to be.) I can also get a rough inside carving which I don't think is "cheating" in any way. All final surfaces are done by hand tools. Finally, I have the ability to make the rough shapes stray away from actual curtate cycloids. This gives flexibility to the method (in making a roughed-out plate.) The shape is in mathematical form.