tango

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Posts posted by tango


  1. 12 hours ago, Davide Sora said:

    Nothing wrong with that, but turpentine appears to shorten the open time for application, while also reducing the possibility of self-homogenization of the colored layer. Then it is toxic, not good if you apply it with your fingers without gloves and for your lungs too. Adding linseed oil in place of the turpentine improves these aspects a lot, with the risk of developing some craquelures. But this should be a peculiar feature of oil varnishes, isn't it? So maybe it might not be seen as a drawback.

    Warming up the varnish make easy to apply with fingers like if we were thinning it with a solvent , isn´it? I saw that it dry quikiest but I don´t know if I may ruin the varnish. 


  2. On 1/5/2016 at 12:57 PM, Davide Sora said:

    Thanks for reporting your thoughts, the book is really worth acquiring for me too.

    I particularly like the predilection of Padding for varnish without solvent and its application technique that I am currently trying and that works incredibly well especially for colored layers, almost miraculous for even paint application.

    Hi Davide
    What's wrong in thinning varnish with turpentine to applying a thin coat?

    The only problem I found was one brand of turpentine bought in a chemical store but now I use Winsor & Newton. I made tests over a glass and W & N left minus tacky the surface when dry.

    I use Hidersine oil varnish. The only one I can achieve here. Sometime I use my varnish but I am a little affraid <_<


  3. On 5/17/2019 at 7:31 PM, tango said:

    Hi all
    Finally I bought two black light tubes : 36w and 120cm long. Special offer.
    Not available 80cm as I wanted.
    I will copy Davide Sora but a little longer. I want to make a cello, so I guess this 120cm tubes may be useful
    Now , reading Joe, I think about distance between tubes and varnish and doubt if it was well.I must test .
    Thanks for all advices
    Regards
    Tango

    Hi

    I have a good results with this set up.

     


  4. 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.


  5. On 7/28/2020 at 12:53 PM, Michael_Molnar said:

    The tannin from quebracho is not a lake, namely a pigment particle. It is a dye that becomes attached to cellulose with a mordant. Grinding quebracho will achieve nothing. I think quebracho is the loveliest tannin. I recall @Johnmasters calling attention to this several years ago in a thread. Cochineal, however, is a made into a lake. Good mulling is needed to totally wet the particles with oil.

    Hi Michael
    I made a lake from the dust of sanding of quebracho.
    I went to a carpentry and bought that :) 


  6. 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


  7. 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


  8. Hi

    Violadeamore. :D:D:D
     

    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


  9. 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 :unsure:

    Regards

    Tango


  10. 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


  11. 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


  12. 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)


  13. On 2/29/2020 at 9:12 PM, Violadamore said:

    I'd advise dissolving the dichromate in a small amount of water first, then mix the two solutions outside, down wind, and away from structures, until you know what it will do.   Shouldn't be a problem done with dilute solutions,, but the glue will oxidize, and adding the concentrated dry chemical to it could cause explosive splattering from rapid oxidation at the surface contact.  My major worry was that someone would innocently mix some +6 or +7 oxidizer with volatile varnish components and create a fireball.

    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? B)

    I guess who you are but may be better to do not discover the secret. :D
    Hoping you are well in this difficult days
    Best regards
    Tango


  14. 15 hours ago, Violadamore said:

    This sounds good to me.  I just wanted to make sure that everybody out there reading this realized that the potassium dichromate is poisonous, and a powerful oxidizer that has to be treated with care.  :)

    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.