David A.T.

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Everything posted by David A.T.

  1. I will try to make 2 rosin. One red with cochineal and one yellow with turmeric. 1st step is the Rosin dissolved in water and 1%KOH I use quantity for 1.5 liter. Now I need to wait few days. I wonder about the quantity of pigments and if I need to extract them with alcohol or to put them direct in the liquid. I intend to precipitate the red with Zn, and the yellow with Al and Fe.
  2. The seller present it as an original. Auction ends soon. https://www.ebay.com/itm/193923893600 I am doubtfull and think it is copy. What do you think?
  3. I did not update for long. I am at the varnishing steps. It still requires some layers, polishing, mounting... Just to share an overview. (Warning : It is amateur work) As we can see, my red varnish is a complete failure. But at least the wood is nice. David.
  4. I just received a red italian oil varnish from Joha/Hammerl. I tried to mix a bit with a part of my varnish. Both are oil based and look like to have same viscosity. When mixed it turned to a paste. Probably it is a proof that I had too many minerals in my varnish. David.
  5. I would be happy to restart the process and post here. But my instrument is just finished. As fresh varnish is required just before application I wonder if it makes sense to prepare it now. I need several month to make an instrument
  6. I think about an other différence. My varnish is still 'usable'. I dont need to prepare a new one while you say it require fresh one for each coat. It is still very fluide. I remenber I added few drops of Aspic before applying it.
  7. Thanks for your video. Your recipe resist to the main player environnemental factors. My varnish looks much more soft (2 weeks aged though) and much less colored despite I used a lot of madder. JM described in his book a red color varnish without use of the iron.
  8. May I ask you if my pink dried rosinate on the above pic looks as it should look? Are the small white particles all around the salts to remove? I may restart some processes with other colors
  9. I tried to find Who was Dietré, but did not found. I am not sure about the 'choix 0' which could refer to the wood/ violin quality. I dont think it is a name.
  10. Hello, First I thank you all for considering seriously my question. The receip follow the book proportion, except for the madder for which I increased the weigth of madder root x5 to produce the madder concentrate. Ground was a thin layer of potassium silicate + calcium sulfate (applied where I found minors scratches). Then few drop of cooked linseed oil that I bought ready made. the oil has a little red color . then the rosin was prepared with 2 receipt, 1st with Alun to get a Yellow varnish, 2nd with Zn (and little Fe) and Madder to get the Red varnish. I f
  11. Jean Dietré choix 0 au Nicolas Rue Croix Lyon 1902 Hello, this is what I read.
  12. Hello Maestronet Experts, I finished one coat of linseedoil/rosin/Zn/Al/Madder self made varnish 2 weeks ago. It is 'inspired' by J Michelman recreations. Varnish is still 'sticky' when the hand is left few seconds on the instrument. It looks dry when touched very fast. It is probably the last coat I will do. While cleaning the neck fingerboard surface one drop of water went on varnish surface and seems to have removed the last layer after few seconds. Is it normal that varnish is so weak? Any clue about what was missing in the varnish? (Maybe Just need to wait more Drying time
  13. The museum bought recently An Amati Cello. The JBV Octobass is also interesting to see. Many things are interesting in fact, and sometimes there are nice events.
  14. When looking at The Saveuse. How can we explain that several (8)pieces of wood (not similar grain) were used by Stradivarius while he had the Dolomites and Alpen very close? Probably it was easy to get at that time what we call today a 2-piece C-class plate but he did not made this choice.
  15. here is how I do. The plates are first flattenned to try to get the lowest defect as possible - it is very long to do, in particular for mapple. then I use 2 flat piece of wood (the bottom one is hard wood) , and the low angle plane at 90°. I alternate 180° each pass through. nothing clamped, just free hand. to alternate 180° let compensate the twisting due to shooting board imperfection. even a 0.1 mm on the shooting board will create a gap. slowly done .very fine piece of wood should get out the plane I don't know how to correct the issue you had. But I had same issuer in the
  16. Exact. That's clear. It is time consuming. To flatten the cello parts before and after is a very big amount of (annoying) time.
  17. Shooting board should be enough. On my last boards I had no Gap without clamp. It was a cello. Main factor is probably how to use the shooting board. I also don t use clamps during shooting, to keep everything free and avoid the twisting. Twist avoidance is key. The twist comes from perpendicularity defect( table flatness, board flatness and plane angle). Even a very fine defect will create a twist. If you use well the shooting board you can compensate : finishing with the smalest plane thickness as possible, then alternate 180deg each shooting. Below some pictures after shooting board. F
  18. I let 3 on my current project. (3 remaining, with channel 2.5)..But I am not an Expert. If you don't get other answer, I can check later today in my notes the information sources