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Michael_Molnar

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Everything posted by Michael_Molnar

  1. And let me add that formaldehyde was applied by spray or brush. It was a surface treatment developed, IIRC, in the late 19th century by paint artists in their effort to minimize moisture issues. My post was meant to draw a parallel between luthiers and paint artists. I did not mean to suggest that the Cremonese were using formaldehyde. I was pointing to the apparent switch from hide glue to casein as an issue of reducing moisture effects. The paint artists felt that casein still wasn’t good enough. Sorry for the confusion.
  2. Degrades it which is why I wouldn’t use it. It is also carcinogenic. But Mayer wasn’t talking about glue. It was about casein sizing.
  3. Funny you should mention proteins. I happen to be reading “A Perfect Ground: Preparatory Layers for Oil Paintings 1550-1900” by Maartje Stols-Wilcox (2017). It appears that artists were switching protein mediums to get a ground that was resistant to moisture. Reading this, I feel that Stradivari’s switching is related to this search. Although casein turned out better than hide glue, it still needed treatment with formaldehyde according to Ralph Mayer “The Artist’s Handbook of Materials and Techniques “ (1991 ed.)
  4. As I said, romantic hype. Thanks for making my point.
  5. I suspect that the secret is largely romantic hype.
  6. I have two theories explaining Echard’s detection of linseed oil in the ground. The first is that he is detecting a thin emulsion of linseed oil and an organic medium used as a wood primer. The second is that his method of detecting linseed oil is being confused by an organic medium that interferes with forming the spectral profile he uses. I am waiting for confirmation of his detection by another research group using a different method if possible. As for particulates in the ground, they are there in Cremonese violins because that was the standard artistic method of the day. I agree with Joe that they are not needed to get a great looking instrument. As I said before, are you trying to reproduce an historically accurate mock-up or a great looking instrument, perhaps better than Strad?
  7. And I like the hollowed out Swiss style pegs. I liked Pernambuco pegs too until I needed to take out a mortgage to buy them.
  8. I bought this years ago from Dov Schmidt when it first became available. Still works.
  9. There is nothing “casual” about using Fusion360. It is formidable.
  10. FWIW, a dry pigment’s color (hue) is different in a medium. I think that’s obvious, but you never can presume everyone understands that.
  11. Barry, Google around for CNC and CAD discussion groups like I do. There are many CADCAM programs with less complexity than Fusion360. You must research this before investing time and money. Good luck.
  12. Well said, Mike. Yesterday I wrote a long opinion on this very issue of using fugitive materials. I was even recommending modern substitutes but realized that no one is interested. (Notice how my previous post’s question about using modern pigments was largely met with crickets.) I understand that most makers think that new pigments cannot match the original colors. Not true. So, I deleted it and moved on.
  13. Yes, but you need to widen your exploration.
  14. I suspect the reason is that the oil is acidic. This is linseed oil? It can be very acid. Look at the information on the Natural Pigments website.
  15. Yes, refractive index can be a red herring especially in the case of thin films which is what we are dealing with. The same can be said about clarity of the ground. And yes, flame contrast depends on how much colorant is absorbed. The mineral fillers are totally unnecessary for appearances. I now wonder whether the fillers were added for acoustical reasons as @Roger Hargrave suggested. The appearance of spruce is not as straight forward as one might think. More on that some other time in a serious thread without the clown car antics. I am still studying @John Harte’s references. Lots to think about.
  16. Kaolinite (Kaolin) is good stuff. It works nicely as a filler and as a surface finisher. I remember learning about the latter in @joerobson’s varnish course.
  17. Yes, I downloaded those papers (good recommendations from John Harte) and am poorer by about a $100 IIRC. The Claudia Invernizzi, et al. paper is very good. The violin of interest for me is Strad’s Cremonese, a Golden Period violin. I’m still studying these papers. Why do some people consistently torpedo threads just when they are getting good? Just asking for a friend.
  18. Joe, I was replying and referring to ctanzio’s list that included mercury, lead, etc. My point is that one detection does not mean it was used extensively. You brought up a interesting point that sounds like you support a model with gypsum.
  19. I was looking for references, but thanks anyhow. Listing detections gives the erroneous implication that ALL or MANY instruments had these. That is not true. The maker and date must be attributed as well. Don’t forget that fiddling is human nature (pun). Your last sentence is my mantra.
  20. Knew you would come through with the facts. Thanks a million.
  21. Can someone save me some time and list the research references that found PoP? Thanks
  22. It’s been many years since I fiddled (pun) with cochineal. IIRC, the metal lake ion can shift the color. In any case, try aluminum salts for carmine. Also, read Michelman. I think the pH of the bath that links the metal ion is also important. Did you search thru old posts here on MN?
  23. I’ll miss doing business with you.
  24. Clear colorless varnish to seal the ground. It shows up under UV.
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