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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. Linseed oil is used to create a protective coating (traditional) on gunstocks. Coat after coat is applied in thin layers until a build is created. It has been used for a long time (since there were guns?). I do not think it has been forgotten. For example, I think it is used on those hand-made English shotguns (something I would like to own). It suffers from poor water resistance and is delicate. But, it is easily repaired. I cannot understand the point of using it on a musical instrument that is subject to wear. Mike D
  2. It has been my experience that shellac can be hardened by exposing to UV in the drying box. Anyone else made this observation? There are shellac hardeners available that will improve the wear properties. Alas, Hard Shellac can no longer be exported from Australia. But an additive to harden it can be shipped from thewoodworks.com.au Urushi lacquer is available from Japan. It is legendary for its wear and water resistance. mejiro-japan.com Some and maybe all spar varnishes contain precipitated silica which will increase the wear resistance. And they can be used on edges. They are also very water (sweat resistant?) resistant. Since the shine would be strange, they should have french polish placed on top. Maybe a thin coat or two would be enough. These are just a few ideas. I do not know of any classic violin oil-varnish recreations that are sweat resistant. My Fulton varnish fails this test, and since the Hargrave formula is very similar, I think it will fail, as well. Mike D
  3. How do we know that it is safe to use a clear film that is self-adhesive to the varnish? What if it reacts with the varnish and lifts the varnish? Has anyone run any tests on this? I think it is prudent to be very careful. It looks like Don has lost the varnish down to the ground. This is an opportunity to practice some restoration techniques. Does this varnish contain any of the cooked iron rosinate that was a recent conversation on this site? Mike D
  4. I think I would start with oil paint thinner which is similar to diesel fuel. Q-tip application. I suspect you will lose some of the varnish since it has reacted with the sweat. This problem is the reason why you want to use a particulate ground--it provides a wear-resistant layer since the particulates are hard as a rock. I know that there is a lot of confusion about whether a particulate ground exists, but it would be useful for this situation. You can reapply your varnish or use violadamore's ideal of applying urushi varnish--perhaps after applying coats of your varnish to restore the color. It would make sense to then apply a plastic , clear tape. But there is always the danger that the adhesive will also react with the varnish. Another idea is the clean the mung off and then french polish it or use your airbrush to spray shellac to get a fast build-up. Mike D
  5. Don--thanks for the reposting on Iron Rosinate--I missed it the first time it came around. Michelman was a varnish/paint chemist; why did he not cook his violin varnishes? Mike D
  6. What is the temperature that you reach when cooking? Is all the resin/rosin added as the Zn and Fe rosinate or is there some colophony added as well to the oil?. You can get a red/brown varnish from just colophony and flaxseed oil when cooked to a high enough temperature (approaching 300 C) but your color density is very dark for 3 coats--perhaps you used a layer of pigment directly on the wood ground which would darken it..
  7. Where does the red come from? Michelman had to use a lake of madder and/or alizarin to add red since iron rosinates are brown by themselves.
  8. That video of the gentleman hating the flaxseed oil on the kitchen stove is amazing. Amazing as in stupid because if the beaker breaks (which beakers do), his house will be on fire. Anyway, his temperature is in the correct range as mentioned by others who contributed to this question. The 95 C processing is not correct. Fulton published a "how to do it manual." Mike D
  9. Page 61 in "Violin Fraud" by Harvey and Shapreau contains an important contribution to faking. This is the reproduction of a letter by a famous violin forger which was written to Edward Heron-Allen in 1894. It is a detailed step by step process for faking Cremona instruments. And parts of this will help you. For example: the faker talks about making a special glove with attached horse-hair to rapidly wear certain areas of the instrument. Mike D
  10. Your middle layer of the Barlow & Woodhouse picture is a mineral layer. The EDAX data proves this to be the case. The authors mention that the region seems to be mostly devoid of varnish. Cold-mixture of oil and resin to make a varnish? Where does this come from? I looked at some FTIR data for a different cooked varnishes going from 1:1 to 1:3 oil:rosin (Echard work as I recall). It was really hard to see any difference in the FTIR responses. If this is really true, it casts double on the B&G conclusions on oil;resin ratio in the varnish. Too much "magical thinking" for me. I give up. Mike D
  11. There is a reality to varnish making that is not realized in this discussion. When you make a 1:1 or 1:1.5 resin:oil varnish, the varnish is extremely thick (almost solid) when the cooking is finished and allowed to cool down. You have to add turpentine to it to have any chance of ever coating the instrument. The amount of turpentine will determine how brushable the varnish will be. You do not need to add uncooked oil for this. Note, during the varnish making step, the oil chemically reacts with the rosin--that is why it is cooked. Personally, I add the thinned varnish to pumice for the initial coat--this is tantamount to using a thick varnish. This is so thick that it is rubbed on. You do not need a special varnish recipe for this. For Mr. Cowboy: I do not have the B & G book. According to those that have read it, the 4:1 ratio is for the varnish adjacent to the wood. So, the components have already been fully reacted (cooked) when turned into a varnish and the wood was coated. The chemistry of the varnish is a mystery for me. The process starts with the cooking meaning that some polymerization takes place during the cooking chemical reaction. This is later completed when the varnish is applied to the wood and additional polymerization takes place to set the film. It is a mystery how a scientist can analyze the film years later and then determine the resin:oil ratio. I am going to look at the Echard papers again. Mike D
  12. Here is another example of Occam's Razor: instead of inventing another varnish composition for cellos, why not use more coates of the violin varnish? Then, you will get a thicker and darker varnish. It may age differently. Mike D
  13. If you read the Nagyvary review of the B & G book, you find that it was never submitted to a peer review before being published. This is a serious problem with the B&G book. So, I do not take it very seriously. I am going to go with Occam's Razor when looking at the famous Strad varnish. What ever varnish was used adjacent to the maple wood is probably the same stuff used above the wood; why have two varnishes around the shop. We all know from personal experience that the spruce must be sealed with something. Occam's razor again--every shop had a glue pot. Glue was probably used on the spruce as well, but probably not as many coates (my surmise). The inconsistency between the Echard results and the Woodhouse results with regard to the mineral layer has never been explained. How about this for a wild idea--all the instruments Echard examined are copies by master forgers. Mike D I edited this to change White to Woodhouse--my error. This inconsistency between Echard and Woodhouse is a big deal
  14. https://www.thewoodworks.com.au/shop/consumable/shellac-hardener/hardener-to-formulate-hard-shellac-polish-detail This is a hardener for shellac. You can also put the instrument in the UV box--shellac will harden overnight. Mike D