Stradivari Varnish oil/resin ratio


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17 hours ago, JacksonMaberry said:

Varnishing with a good spirit varnish or a good essence varnish appears to do precisely the same, given the quantity of excellent violins that use these methods. I don't disagree with your observations, but the effects are subtle when good practices are followed and extreme (in the negative) when any kind of finish is overapplied.

I don't mean to suggest that white violins are more tonally optimal, sorry. But I get my hackles up when varnish is spoken of as a major beneficial tonal/timbral component, as it frequently is in pulpy newspaper articles and unfortunately occasionally in trade periodicals. It is not.

spirit varnish does not sound like oil varnish

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This is an altogether interesting thread.  Thanks to those who have provided in depth research.  What I see hear largely agrees with what I have learned from turn of the century varnish making texts and 30+ years of varnish making.

As I have said many times I am a cook not a chemist.  I read and for the most part understand the chemistry involved with varnish making.  However a list of materials is not a varnish recipe.  A varnish recipe may or may not lead to a useful and repeatable varnish.  The varnish made may or may not have the characteristics you desire.

Obviously varnish making is interesting and in certain cases addicting.....

I offer one piece of advice:  if you want to explore this process, choose a resin and stick to it.  A particular resin will produce differing outcomes according to how it is pre-prepared [or not] and how it is combined with the other elements of the varnish.

My choice is the American Slash Pine in both raw and colophony forms.  Through a long and other story I have acquired the resin purchased by Louis Condax [CONDAX, Louis M. Born 1897, died 1971 Rochester, New York USA. Research chemist for Eastman-Kodak. Amateur violin maker from c.1920. Later worked with Simone Sacconi on analysis of classical Italian varnish. 40 instruments completed  ] for his experiments.  Otherwise I use raw pine resin.  I am familiar with the chemical and physical make up of the resin and have thrown away tons of varnish learning to use it to my specific intents.

on we go,

Joe

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On 8/21/2020 at 1:39 AM, uguntde said:

Oxygen dried linseed oil would keep some double bonds which are required for fluorescence.

Fresh oil doesn’t fluoresce. The aging process develops fluorescence. So, it must not be simply a process of retaining certain bonds, but developing others that either fluoresce or no longer prohibit fluorescence. 

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On 8/17/2020 at 10:05 PM, John Harte said:

There could well be.  What Echard has noted in various papers might support this.  BB's findings possibly suggest that there may be a little more involved.  This remains an area where the jury is still out.

Thanks John.

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On 8/17/2020 at 4:10 PM, David Burgess said:

In general, I am willing to offer highly experienced counterpoint to myths of any kind. But in this particular case, it is targeted to shellac myths.

Some people highly appreciate stuff like that, and others don't.

I probably could find what I'm looking for tonally by mixing various ingredients with shellac.

I believe the varnish should go from softer ground to gradually harder layers.

 

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On 8/22/2020 at 5:57 PM, Michael_Molnar said:

Fresh oil doesn’t fluoresce. The aging process develops fluorescence. So, it must not be simply a process of retaining certain bonds, but developing others that either fluoresce or no longer prohibit fluorescence. 

You must be wrong according to Sherlock Holmes who traced a crime by using fluorescing linseed oil. https://bcachemistry.wordpress.com/tag/sherlock/ ;)

My assumption is that abetic acid esterifies with the glycerole from linseed oil, and this is what happens when we cook varnish. This process alone is known to make a varnish (see lipid reactions lecture).

The fatty acids in lineseed oil then get polymerised when varnish dries as explained in the Sherlock article. There may also be other sorts of reactions which are UV light rather than oxygen induced cross linking (after all violin varnish dries under UV light).

Whether the abietic acid glycerol ester cross links with fatty acids I am not sure. There are articles claming that they undergo Diels Alder reactions (although with phtalic anhydride), but also with Tung Oil (Guozhang Ma article). Diels Alder reactions require UV light.

The fluorescence arises probably from free fatty acids embedded in the varnish and there are good reasons to believe that this looks different when they are immobilised in a solid.

Some of the source of my wisom is attached, but I have collected lots more articles which I can make available should anyone be interested.

Biobased-Thermosets_link.pdf 07 Lipid reactions.pdf optimizing-catalytic-drying-of-paints-and-varnishes-case-study-at-smalto.pdf Ma_et_al-2013-Journal_of_Applied_Polymer_Science.pdf

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I forgot that Sherlock Holmes was a research source. :)
 

Yes, there are a number of papers that come up with googling. They explain how aged linseed oil eventually fluoresces. Old dried  linseed oil glows and looks opaque under UV. Recently, I was rereading B&G and noted that Greiner p.29 said that the fluorescence takes a few years to develop fully.  Varnish, however,  glows on day 1 and remains strong for centuries.

Do not confuse linseed oil with varnish. The fluorescence of varnish, new or old, is mostly due to rosin (colophony). 

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38 minutes ago, Michael_Molnar said:

I forgot that Sherlock Holmes was a research source. :)
 

Yes, there are a number of papers that come up with googling. They explain how aged linseed oil eventually fluoresces. Old dried  linseed oil glows and looks opaque under UV. Recently, I was rereading B&G and noted that Greiner p.29 said that the fluorescence takes a few years to develop fully.  Varnish, however,  glows on day 1 and remains strong for centuries.

Do not confuse linseed oil with varnish. The fluorescence of varnish, new or old, is mostly due to rosin (colophony). 

Partially true, yes, although the fluorescence of oil varnish DOES get much more intense over time. 

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On 8/27/2020 at 6:22 AM, pbelin said:

My freshly applied varnish is strongly fluorescent white, and upon drying it becomes duller and goes towards an orange fluorescence. Can anyone explain that? 

I'd put money on sospiri or uguntde having the theory.

My guess is an ingredient from the tube may have something to do with it.  Mine goes darker with some sheen loss - hope it stays where it's at.

edit - I use a quart glass jar for holding spirits of turpentine so that it can air out before use for varnish making - I notice the dried out residue on the inside of the jar has the same dullness/sheen that I think I notice on a few of my later violins - [recipe change].

It is a sheen that is glossier than a semi-gloss from the hardware store but not as luminescent as a violin by Mr. Ouvry that I have. 

Then there's always the possibility of linseed oil changing everything like Ugun explained above. 

Fluorescence?  I'm not familiar with what I should know about it- haven't reached my level of incompetence yet.

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4 hours ago, Michael_Molnar said:

I’ll hazard a guess that you are seeing the solvent dominating the fluorescence at the start. As it evaporates or dissipates the roasted rosin is left to fluoresce. I’d need to do some simple tests to evaluate that hypothesis. 

Fully agree

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