Modified 1/2021
Page G_09
..Fuller's Earth used as Violin Varnish Ground....( 2017)
..Varnish makers and researchers alike have attempted to understand how the Golden Age violin makers varnished their instruments to produce that Sound.
..The tone of these desirable instruments had the characteristic of dampening the overtones above about 2,300 HZ; thus giving a quieter and purer / more pleasing violin tone.
..As part of their research, they have analyzed small samples of the varnish ground layers of these violins and determined the chemical composition thereof. {See the Journal of the Violin Society of America 'VSA' papers, various volumes...}
...The very interesting thing is that these type of element groupings are just what Fuller's Earth contain.....
Fuller's Earth
Alternate Names: Bleaching clay
Oxide... Analysis... Formula...
CaO... 2.00%... 0.209
MgO... 5.00%... 0.728
K2O... 1.00%... 0.062
Al2O3... 10.00%... 0.576
SiO2... 65.00...% 6.349
Fe2O3... 4.00%... 0.147
LOI... 10.00...
Oxide Weight... 510.76
Formula Weight... 567.51
..Here is an summary analysis from an Internet site.
..Notice the strong similarities to the above graphical analysis of varnish ground!
..The winner of the varnish ground sample tests is:
..
- The outside surfaces of the plates and ribs are: Hematite Burnished twice; then Dutch Rushed twice; then:
- A combination of: the varnish ground of (4) grams of Fuller's Earth mixed with enough varnish to make the first two coats of varnish (ground) for the violin.
..I have found it convenient to mix in the coloring with these first two ground coats.
..Brush these on evenly. They dry fast and can probably be applied the same day.
..This is followed with another two coats of clear (or colored) varnish (one day drying in a UV box between coats) to complete the varnishing.
..
..The result is a rich, mature varnish that reduces the loudness of much of the unwanted overtones (above about 2,300 HZ).
..Unless I am mistaken, this might be very close to the traditional method used by the best Cremona violin makers of the 1600 and 1700's.
..
(c) 2020 David Langsather
...Most of this 'research' took place in the fall of 2016. It began when my wife, who was reading a novel about Sherlock Holmes, asked me: 'what is Fuller's Earth?"
..In the story an engineer was lured to a desolate location by the cover story of attempting to mine this mineral from under a neighbors property without his knowledge. My wife figured it must have particular value but did not know what it was... I looked it up in my Engineering handbook of materials and when I read the typical chemical analysis of Fuller's Earth, I was immediately reminded of the violin research articles on the topic of varnish ground ingredients {in the : Journal of the Violin Society of America 'VSA' papers} and looked them up again. I was so surprised how very similar they were!
..It made perfect sense to me that craftsman of the 16th and 17th centuries would probably have used locally available natural materials in their violin making.
..I devised a series of violin plate wood samples covering the possible combinations of use, ordered samples and then made and evaluated the samples; both by ear and by sound analyzer.
