Greg Sigworth

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  1. Reviewing my physics course work the speed of sound is dependent on the medium the sound is traveling through, not on the frequency of the sound. Mention was made to some differential equation which I did not look up, but I believe that is a misapplication of an equation. The sound radiating from a violin travels at the same speed regardless of the frequency. If the higher frequencies travel at a faster speed it is because at very high frequencies, above those we are concerned with, the wave length is close to the size of the air molecules in air. At that dimension the model for sound in air breaks down and the molecule size becomes a factor actually decreasing the distance the sound has to travel. But you are talking about very very high frequency sound waves.
  2. Thanks for the information. I will try it again. Turpentine has a rather low boiling point so I will be careful heating it up. The Amber colophony does not have amber in it (I believe). This is a reference to its color. It should dissolve in turpentine. I am not making a varnish, but a base ground that I can apply to the wood before I seal it and varnish. I do not want linseed oil in it as I believe that in the wood is harmful to the sound of the violin.
  3. I purchased the amber colophony also and wanted to dissolve it in turpentine. Has anyone had success doing this? Kremer's rosin oil is said to be colophony in turpentine. I did not want to have any linseed oil in it. Thank you.
  4. Great article: could someone please let me know what dG stands for. I know the names of the Guarnari family makers and del Jesu. I want to know what dG is a shortened version of. Thank you.
  5. The answer is ONE and this must be taken from the violin that has the BW lable.
  6. A very passionate subject to consider. If the goal is happiness and fulfillment then the pay back of an investment should be measured by the many years of having played the instrument and maybe someday using it to get a better instrument or maybe give it to a good friend. I am too old to move to Cremona, but if I did it would be to learn the techniques used there to make better instruments, not to jack up the price of a violin.
  7. Well hear goes and I will try to not be too wordy, though my wife says I give too much information, always! In the book The Violin Maker, Samuel Z. is being followed by the author as S.Z. makes a violin for a client. When we get to the finishing he lets the author see him apply his "sauce" as a sort of ground. I assume this portion of this book is true and not fiction. Some medium brown liquid is applied by rag, brush and finally by hand. S.Z. states that OSHA would not like this. A heat lamp is used to help "melt" the liquid and bind it to the wood. It gets quite hot and the author has to back away. S.Z. states that he (the author) is seeing what few have seen. Makes a good read, right! The author then sees a puff of smoke coming from one of the F holes, or so he said. When this step is done the violin goes back into the light box and then will have varnish applied. S.Z. also states that some things must remain secret when he is asked about the content of the sauce. Before I go further I could be wrong on the details from the book, but I recall these facts and you should read the book for yourself to check it out. And I hope I am not wrong doing this post. OSHA, heat lamp and smoke; what do these clues point to? I came across the following which seems to connect these mysterious clues. Magicians use a pasty substance called "Magic Smoke" or mystic smoke. When rubbed between the fingers the right way it gives the appearance of a puff of smoke. As S.Z. rubbed his fingers over the violin with the heat would drive off the liquid which I believe is some turpentine and then this fake smoke could appear. Magic smoke is made of turpentine, rosin or colophony and possibly some waxes. I actually bought some of the Mystic Smoke and thinned it down with turpentine and it could then be applied with a brush. I am going to pruchase some of Kremer's thick rosin oil and experiment with it, possibly add some mastic to it and then apply it as a ground sealer. Has anyone used rosin oil with other items added as a ground coat? The MSDS for their rosin oil stated care should be usedto keep it off of skin, OSHA?
  8. A possible difference between egg white and hide glue would be that the dried egg white will not come back to life when wet; while the glue becomes liquid again. I was led to believe dried egg white is a barrier to water. My first few violins I cracked an egg and applied the egg white on with a brush, didn't even whip it first. A light sanding after the first coat and then another light coat. I may return to this sealer again. I guess I am looking for the perfect ground and the simplicity of egg white seems to be too easy to be that good, but it worked quite well and prevented the oil varnish from penetrating the wood.
  9. Question: What is the reason or advantage of using a CNC machine? There is something inside me that says,"I can make violins faster and then make more money." The cottage violins of the 19th century had this reasoning as a driving force behind their production, and modern China is another example. In industry this also becomes a goal that effects everything else. To put it bluntly, making good violins no longer becomes the main purpose. It is replaced by the desire to make money. Ford motor Co. isn't in the business to make cars; but to make money. Better or faster? A CNC approach could let someone make many plates faster and in an experimental situation this could be good; testing out a new idea. But in life these two goals: make a better violin vs make more violins for money are not friendly to one another. True, you men and women (caught myself on that) who make a living with this craft have a tough road ahead. The faster philosophy usually becomes a company or loose organization and the money motive them steam rolls all else. Well, what killed the Golden Era violins? Maybe the bean counters who said, "Lets make them faster with a CNC machine." A one man operation may be able to keep from from being lost to the "dark side". I am fortunate that I have been infected with this disease of violin making and do not need to survive on its income. When I carve the scroll by hand I am tempted to buy a CNC part; but it is the discipline and experience of that work which elevates the rest of the instrument to be better.
  10. Went back and looked at the pictures. That is one demented violin. Who ever made or worked on it sure used good glue and deserves credit for it still being together with all that present strain. Its history would be interesting. Went through a couple world wars maybe? Reminds me of the adage, "There was a crooked man who lived in a crooked house". Thanks for the pictures.
  11. Just following the comments on this subject. I find that knife sharpening is a skill set which can be difficult to acquire and I am on the learning curve myself. But I do have a backround in metallurgy and heat treating which is helpful in selecting the right steel. The content of the steel is important as it sets the limits the steel can attain to, but the heat treatment is all important and can make the difference between a piece of crap steel and something that is just wonderful. M2 steel has great potential but the heat treatment is difficult and needs a high temperature for both the pre-quench and temper treatments. Powder metal can be any type of steel, even M2. It simply refers to the method of manufacturing. Metal powder is compacted under high pressure and sintered to make the steel avoiding the segregation of alloy content that normal solidification causes; it is very uniform in content. I have seen very good steel make crap cutting tools because the Chinese forgot to heat treat it properly. Find out what your steel is and from the internet you can see the time and temperature needed to heat treat it properly. Problem is you need a protective atmosphere at higher temperatures. If you are a do it yourself person one thing you can do is double temper your steel. Simply do the temper twice and this, especially for some of the exotic steels, will take some of the brittleness out of the edge. As long as the temperature is controlled it will not hurt the steel and can only help.
  12. Carbide steels make good burnishers. Tungsten, chrome, or other elements like moly will form carbides with the carbon and they act like little hard pebbles in the steel, they are very hard and will not wear away. Those steels will sometimes produce hardness in the low 70's RC. They will turn an edge and never wear away or wear off. A very good way to test metal like this is to take an old file and drag the corner of the file on the steel. If the file just bounces over the steel it is very hard and would make a good burnisher. Mill files can be used this way to quickly check the hardness of another steel. Files are usually around 60 HRC.
  13. If you want a scraper which has a curved burr edge produced from a burnisher, fully hardened tool steel will not work well. Spring steel like the kind in car rear leaf springs will be about the right hardness RC 35-45. The RC value of steel is a measure of its ability to resist plastic deformation which has to happen when making the burr edge of a scraper. Fully hardened un-tempered carbon steel is going to about RC 62-64, impossible to deform and very brittle. If the steel is too soft, like coat hanger steel, it will not hold an edge or burr for any length of time. Any full hardened steel will be softened if tempered at a high enough temperature. It can be brought down to the desired hardness. The maximum hardness of any steel is determined by the carbon content of the steel, all the other elements in steel effect the ease with which is can be hardened and other things like corrosion resistance. . The actual structure of the steel is as much a function of the heat treatment as it is the material content. If you find a piece of steel which works well, it has the right carbon content and heat treatment to do what you want; find more of it and use it. Well, this is another whole area of knowledge. The temperature to temper steel to get a given hardness is different for different steels. If you have plain carbon steel and want to soften it a bit put it in your wife's oven at 400 F if she will let you for one hour. Steel should be at temperature for at least one hour to temper.
  14. Don: If it is still for sale I will buy all the glue and the bridges as you stated. I can be reached at GOSigworth@aol.com. I would be glad to send you a check at the address you give me and you can ship after the check clears. Greg Sigworth
  15. On my first violin I made patterns from thin aluminium sheet and I still have these. They were the front plate and longitudinal and transverse patterns and the neck and scroll pattern. No mater how you make these you still have to get down to the line you want to end at. I put the original paper pattern over the metal, used a heavy needle to transfer the line to the plate with pin pricks every 1/8" or less when needed on sharp curves. Then with a good sharp utility knife I connected the dots with a good scribed line between them. Go slow on this. This could have multiple passes. The metal when worked between the two hands easily fatigues quickly and splits on the scribed line. This results in a very good accurate pattern. A wood block with good sandpaper is used to smooth the edge. Any roughness or deviation from the desired shape is no greater than half the width of a fine pencil line. Also, if your first attempt fails just get another piece of metal. No scissors or cutting with bent over edges, no saws to use. This takes a little bit of time but is simple and worked for me. I still have some of these original patterns. They were simple to make and very accurate.