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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. I would give up on this one. The OP has given us almost no information. We know it is a Shadow transducer but not the model--some have a preamp and some do not. Shadows have different transducer mountings. No info on the make of cello. No pictures of the setup. Mike D
  2. I do not think piezo-electric transducers have a significant frequency dependence to the response--so, it cannot be that. But this seems like a transducer problem: Take a look at the placement of the transducer--make sure it is located per the manufacturer's instructions (and that it is the correct transducer for this application). If this is a cheap electric cello, the problem may be a badly designed transducer. Sorry, my crystal ball is still being worked on. Mike D
  3. I enjoy watching Jacob poke at the members of MN. And it always get a response which is probably gratifying. Reminds me (a little) of Pres Trump and the U.S. press. Trump is always playing with them, and the pundits always fall for it on talk TV. Mike D
  4. Behlen makes a series of B370 'touch-up powders' which are claimed to be soluble in oil-based and shellac-based mediums. There are some nice, practical browns in the collection as well as burnt umber and burnt sienna. I have not tried them; so, I am just passing this on. They are not very expensive Mike D
  5. I have looked the paper over a couple of times. It is a useful review of scientific and anecdotal work on bridge tuning. I am convinced that bridge tuning has an effect on an instruments sound. What is missing is the conclusion. How do you adjust a bridge to solve or improve instrumental problems? I do not see any mention of "The Little Red Books" from the Chimney's Workshop which have some guidelines for bridge tuning. Mike D
  6. There is no question that Professor Hesse' device works, and they are still available. The unit is glued into place on the inside of the instrument. The problem with it is two fold: (1) the location of the wolf resonance can change with time, season, humidity, but the resonator is fixed in one place, and (2) it can dampened the sound too much. I think it is safe to say that you always lose something in the cello response when any of the wolf eliminators is used. The Krentz is the latest of these devices, but my research indicates that any collection of weights (multiple magnets) that weighs 35 grams will work as well as the Krentz--the air resonator in the device does not do anything. In most cases, the simplest is the best--namely, a weight placed on the C or G string afterlength. Mike D
  7. This is not a sound post issue. Put the brass thingy on the G-string afterlength, move it close to the bridge (experiment), and get the wolf on the G-string under control. It is likely that the D-string wolf will disappear. Mike D
  8. I am impressed by the repair, particularly by the way the inner piece of new wood locks into the original bow-tip. Very intelligent repair. Mike D
  9. I assume that the OP does not have the piece that is broken out because the easiest repair would be to glue it back into place. I would square the break and make a square plug to fit. This can be done by hand using the old fashioned chalk technique though a mill would make the work faster and more accurate. I would use G-2 epoxy for this over CA glue or hide glue (with formaldehyde), and then remove the excess wood after drying. I would give it a few days of sunlight to darken the wood, and then start the coloring process to make it invisible. I did not think hide glue would work with an oily wood, and that the treatment with formaldehyde or glutaraldehyde would solve the problem of an oily wood. This is new to me. I did a literature search but did not find references dealing with glue strength, oily wood, and the aldehyde treatment. Mike D
  10. I was about to solve this problem for the OP when the batteries went dead in my crystal ball. In reality, we cannot solve this problem over the internet--you have to take it to someone who has the background because there are multiple causes for this.. The easiest and most practical fix is to find another violin. My experience is that reworked instruments never sound as good as one that was built correctly, the first time--that is the problem with taking instruments you purchased in the white and reworking them Mike D
  11. Do not believe that you can sharpen using this wheel without much heat. The boron nitride is a very thin coating on the wheel surface, and it will soon load up with ground particles from your tool. Now it is tool steel grinding on your tool. Heat will result. How do you clean this wheel so that there is a fresh grinding surface? This is easy to do with a traditional ceramic wheel either by fast wear or by the ability to renew the surface with a diamond shaper. HSS is a special tools steel that can take higher temperatures than traditional carbon steel. It was developed for lathe cutting tools; not wood cutting tools. These grinder wheels were developed for HSS. This sounds like another great idea that falls flat on it face. Mike D
  12. Years ago, I purchased a lot of Pfeil tools from Fine Woodworking--mostly, they were too soft, and I sold them on ebay. This is most likely a manufacturing issue in the head treatment shop since it is unlikely that Pfeil makes its' own steel. More recently, Pfeil steel knife blanks have worked OK for me. If you are going to intelligently comment on the best steel, it is vital to know what the steel is (composition). It is extremely difficult to sharpen thin steel blades without accidentally softening them from overheating, and then you blame the manufacturer for an error you made. Thin blades must be sharpens either very very slowly using say a hand rotated grind stone or ground under water. This issue of the best steel never goes away. The old steel gouges that everyone loves (and sell like hotcakes on ebay) were most likely O-1 steel. Mike D
  13. As an American, I always reach for a handgun, and I shoot the peg out. I recommend .22 caliber for this application. On the other hand, if the OP had done a tiny amount of research, he would find lots of useful advice on this problem Mike D
  14. I have noticed the same thing. I would cut a small disk of kitchen wax paper and place under the top magnet. The wax paper is slippery and will also separate the padding material from the varnish. I do not know if the padding material is reacting with the varnish or this is wear due to the top moving up and down and the magnet slightly moving with the motion. French polish will probably restore the luster. Mike D
  15. Do not make this too difficult. You can buy blue steel shim stock at McMaster-Carr which makes good scrapers. They also sell tool steel (O1, A2, etc) in a wide variety of widths and thickness for blade making. You do not need those new and exotic particle metallurgy steels for this work. Spend your time and money on making instruments or repair. Mike D