Jump to content
Maestronet Forums

robertdo

Members
  • Posts

    2737
  • Joined

  • Last visited

Posts posted by robertdo

  1. I think that authors give away their copyrights to the publisher for a certain amount of time. So I would think that even in case of death of the author, the publisher has latitude to give permission for pictures reproductions

  2. this "dark colophony" is not really that much darker than the usual colophony.

    Cooking inside a wood stove could indeed be a (funny) way to cook rosin. But to honest, reading this thread makes me feel like people are dealing with atomic bombs. I mean when you melt 30g of rosin at 100-200C on a large container on top of a heating plate in your garden, what kind of cataclysm can you expect? We are not talking about kilos of rosin cooked at 500C inside a non ventilated area with tens of kids running around.

  3. Looking back through my photos, it appears I lost all the colour when mixing with the alum. (Maybe someone sold me flour on ebay...)

     

    This is my filtered madder water

    https://www.dropbox.com/s/bsus5v68okeaat1/IMG_5557.jpg

     

    Mixing the alum solution

    https://www.dropbox.com/s/d795gedczxqvb02/IMG_5564.jpg

     

    The precipitating pigment

    https://www.dropbox.com/s/5557ctjbwd954kq/IMG_5565.JPG

     

    which turned to a beige slurry, rather than a nice red one

    https://www.dropbox.com/s/as5jlan360ge0q6/IMG_5567.jpg

    So how is your madder lake making going? Did you try again?

  4. I mus stay that the first picture doesn't show the right colour at all. It should be much much redder, a real deep red. It's strange because the picture you showed earlier in the thread seemed red. the problem comes from the lye solution I would say.

    Also after filtration there should be no particules left in the madder/lye solution. It seems that you still have a lot of debris.

  5. the strange thing is that once the madder alizarin is dissolved in the lye solution it becomes very red due to the basic pH (and it looks like it's really red on your picture). Precipitation with alum should not change the pH enough to lose this color. Do you remember if the color was still red when you added the alum? Did the color fade afterward?

  6. the colour looks right in the lye solution. After precipitation in presence of alum it should stay that red.

    Yes, 10g in the volume of varnish for 1 violin is too much. I can't give you a number but the best way is to experiment.

    What was the molarity of your sodium hydroxide solution?

  7. when you soak your madder roots in the lye solution it should immediately turn purple red. If it was not coloured at that time then there was already some problem with the lye solution most likely.

    you don't add 10 g of madder lake to varnish 1 violin... :)

  8. Morning Roger

     

    Now why on earth would I want to do that, concidering all the kind and open minded answers I got to a simple question :rolleyes:

    Anyway, if it's allowed to ask a little bit more, it is still a forum i guess. Is the answer that James gave the only clue to why the purfling was inserted after the soundbox was closed?

     

    Again, I'm not questioning the evidence only trying to kindly ask.

    Even if it was the only clue, what would be the other logical explanation for the pin to be consistently cut in half by the purfling?

  9. I know why. Its because on my MN profile I gave my age as 104 years.

    Strange.  At the age of 104 I would have thought people would receive adverts for coffins, soul sale or insurance against vampire hunters... :)

    Believe it or not once I was in a plane and read one of these books they usually provide in the seat back. Inside one of these books I saw a very serious advert for an insurance company selling insurances against werewolves!

  10. When I made some 1704 varnish the resulting color was very red/burgundy and this only comes from the seedlack used in the recipe since all the rest is colorless. So indeed you can get color out of the seedlac. But I seem to remember trying to melt shellac into oil to make some colored oil varnish and the shellac never got into the oil. So I as under the impression it was insoluble in oil?

  11. I would be surprised indeed to learn that the color "amber" always relates to the resin amber. this can't be since the color is nothing special and amber resin comes in many different shades. You can most likely cook colophony to get many different shades of golden yellow, amber or brown.

    Remembering discussions we had here about varnish, the main argument for the presence of some amber varnish was that the "ground" of Cremonese varnish seemed to be much harder and resistant to wear and solvants that the average sap varnish. Given that amber varnish has this reputation of being very resistant (and given that the ground is usually described as golden yellow) the presence of amber was a possibility. Hard data for this presence however is very scarce or even non existant.

×
×
  • Create New...