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Everything posted by tango

  1. hi david I don´t remember well but it was some like this I made a Lake pigment mixing quebracho sanding dust in a jar with "carbonato de calcio" wait for the time needed then added alum . Waited for decant and siphon clear water. I repeted that several times. Filtered that and let dry and so obtained the lake pigment. I made two. One of pernambuco and one of quebracho.
  2. Hi Michael I made a lake from the dust of sanding of quebracho. I went to a carpentry and bought that
  3. Ķ

    Hi David
    I am trying my first violoncello. 
    I like this set up for glueing plates because have few elements and well thought.
    Do you use that nowadays?


  4. Hi I am understanding a little joining replies. As I insisted grinding the color was getting some dark. I guess it was due to the "quebracho lake" (tanins) not the cochineal because I tried a couple of test and cochineal didn´t change during the grind with muller. I will pay attention to the medium used in the grinding process (Turpentine, oil or varnish) Thanks all for your help Tango
  5. Hi Two weeks ago was the first time I grind natural pigments. Previously I mixed some oil tubes colours with some synthetic powder pigments using a muller over a glass. This last time I grinded cochineal powder from Kremer and a lake, made by me, from a tree called "Quebracho" (Schinopsis balansae), very rich in tanins. I never noticed any change in color grinding sintetic pigments like Quinquasia Gold or others but with this two natural ones I saw a change in color as I insisted grinding. May be that natural powder brake into pieces and free some hue? I grind with some drops of oil, a little of turpentine and finally a little of oil varnish. Then mix all with varnish. Thanks in advance for opinions Tango
  6. Hi Violadeamore. Jezzupe. I guess the power plane vibrate so much. It would be ok for the first aproach . Isn´t it? Michael. I thought I was the only one that chalked the back centre joint. Always work a lot between curled maple becauuse a very little light is there (without clamps) David. I found an old (2008) photo of your gluing system for cello´s back using glued wedges. I like that. Thanks all for advices an information Tango
  7. Hi all After two years of postponement I began a cello. At the present time I only made 10 violins and 3 violas. Some top plates were rubbed and some clampled as all my back plates being this backs the most difficult task. 1)Is there any trick for planning centre joint in the case of a cello? 2)Somebody used a shooting board for cellos back? 3)Is any method preferred to other? For the moment I am thinking to work as always but I am a little affraid Regards Tango
  8. Ok. Thanks all for replies Tango
  9. Hi Temp in the top of the cabinet is 18/22 C°. The cabinet is 120cm x 80 cm. We are in Winter in Buenos Aires. I guess the stuff to be aware is the temp, isn´t it?
  10. Hi How close to the UV light tube must stand the violin in a UV box ? (Black light , 36w and 120cm long) Tango
  11. tango

    Yellow for ground

    Hi. Sorry the long time from my first post. Finally I did not add shellac with turmeric. I used an uv box , made on last november, for darkening some. I am happy with results. Thanks all for advises. Regards Tango
  12. Hi Three years ago I made diluted turmeric in alcohol. Then filtered that and used the yellow alcohol to make shellac. Unlike the turmeric only diluted in alcohol without shellac that dissapeared soon. This resulted a nice yellow ground, the best yellow I made and lightfast. I saved a sample. It is not a "desired golden yellow" but is the only acceptable yellow for ground I was able to make. Because I seal the wood with oil varnish and plaster of Paris I was thinking about transfer the turmeric from alcohol to oil. May be boiling the alcohol with the oil until the alcohol is evaporated completely ? I know I can coat the wood after sealing with P of Paris with the yellowed shellac but I refuse because , to achieve a nice color with oil varnish needs a lot of coats and I don´t whant add to much to the wood. I am overthinking? So, the question is: Can I transfer turmeric powder in alcohol solution to linseed oil? Thanks in advance Regards Tango
  13. Hi This is mine: a 40,3 cm viola.
  14. Hi I made my test with potassium dichromate and still am alive haha. For some reason the darkening effect is little. I will apply a coat once more. May be I diluted a lot the potassium
  15. tango

    Viola rib height

    Hi Okawbow I am making a 40,3 viola of my desing. 37,8 mm rib at the bottom to 35,5 at the neck.Same archings height as you. Stop 221 mm. As time pass I doubt about meassurements but now it is too late to go back haha ! About fiteen days I expect to close the box . May be I will test before varnish (I am ansious)
  16. Hi Davide Very nice. I wish you are well
  17. Hi Viola D´amore. I beg your pardon for the delay of response. Just now I am opening Maestronet after very much days without opening this. Thank you very much for advised me, I apreciate a lot your comments. I guess you are one of the most important restorers in USA ¿Aren´t you? I guess who you are but may be better to do not discover the secret. Hoping you are well in this difficult days Best regards Tango
  18. Hi. Thanks you all for useful information. Viola D´amore. You scare me :). Y sincerely thank you for your caveats. I was thinking to use gloves and mask but now I will read more about safety. For the first stage on a white violin I was thinking to make half a litre of very diluted glue with a little spoon of Potassium Dicromate. What do you think? Of course I will try first in crap wood.
  19. Hi This is my first time. Do you seal the wood before apply dicromate? I will test in crap wood first with seal and without. Thanks in advance for any advise. Regards Tango
  20. tango

    Viola rib height

    Hi Louis As always you are very kind . Tango
  21. tango

    Viola rib height

    Hi Louis I am deciding the meassurements of a viola I will make soon. I was reading your post because you make violas with sucssess; so I have faith in your words. The past year was asking about some imformation about meassurements to make a 40,3 cm viola .Now, the mould, has blocks glued . They will be about 37 mm (when finished). Question: Are brecian´s archings prone to bring a warm sound? I don´t like violas with violin sound. Regards Tango
  22. Hi Mampara What is the powder added near the final stage? (Sorry, I speak spanish)
  23. Hi. I seal the wood with plaster of Paris miced with oil varnish. The only lycopodium I know is an homeopatic remedi