The varnishes of the Italian violin by George Fry.

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It is a tremendously interesting book. It contains a lot of information about varnish making and varnish ingredients in general, and it is truly scientific from the point of view of describing chemical experiments from which Fry draws some conclusions.

Unfortunately, his premise is based on a blind belief that the basis of Italian varnishes is nitrified colophony. The varnishes derived from this are totally useless - they absolutely never harden. I have made most of his recipes myself, and applied them to instruments. All eventually had to be stripped. Every characteristic of Italian varnish which he describes he claims to be present in his recipes. The one practical problem is that the varnishes don't dry. On the other hand, all the characteristics he claims for his varnish recipes are also apply to pine-resin/linseed oil varnishes, with the exception that these do in fact dry - very quickly, in fact (with the assistance of UV and heat).

One interesting episode in the book describes, almost in passing, the formation of beta-pine terpene resin during the course of one of his experiments.

Beta-pinene terpene resin is derived from oxidized turpentine (gum spirits). It is therefore a pine resin (abietic acid), but unlike colophony it is pH-neutral. There seems to be s strong concensus that the old Italian varnishes contained mainly pine resin and linseed oil. Beta-pinene terpene resin only needs to be cooked with linseed oil to produce a very fine varnish, whereas colophony has to be treated first to render it pH-neutral.

The book is not expensive. I have no problem recommending that you buy and read it, but the varnishes don't work. That does not mean that the book isn't very interesting and informative.

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Hi Jacob, GM22,

Jacob, I completely agree and concur with your experience with Fry varnish.

GM22, I would recommend Bill Fulton's book as a more useful, practical manual for varnsih making.

I've also published a simple recipe for making an 'authentic' oil varnish on M'net. If you want to try it, let me know since I have made some small changes to the recipe.

Oded Kishony

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What I like about the Fry book is that it tells one what chemical reactions are taking place during his experiments - it is scientifically much more detailed than Fulton's book, if one likes that sort of thing.

As far as the latter is concerned, it is more "practical" than Fry's book, although it contains chapters on varnish recipes which he subsequently turned away from himself, and which to me look to be of little use. The terpene-resin varnish recipe is obviously very useful, as are some of the chapters on varnishing methods such as glazing, using emulsions, etc. It is helpful to keep track when each chapter was written (the book is in fact a collection of artcles spanning 17 years), because, as I've mentioned, he dumped some of his own ideas during a process which, as far as varnish recipes go, culminated with the terpene-resin recipe.

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  • 7 years later...
  • 3 weeks later...

As far as I understand there are two approaches to make a linseed oil varnish. Please correct me if I am wrong.

There is the varnish where some resin is cooked in linseed oil at high temperature. This is the Fulton type, and seems to be what everyone uses now, in some form or another.

The Fry approach dissolves rosin (which is a resin) first at high pH, i.e. under basic conditions, in its original form using lye, followed by the precipitation of a salt (e.g. with alum). Michelman describes this process in great detail, and takes a somewhat scientific approach, using simple stoichiometric measurements. He clearly describes the chemistry of the reaction of rosin with various salts. This is the most scientific approach I have seen.

Unfortunately he skips the chemistry of linseed oil reacting with the rosinate, because his recipe lacks this step. This is why these varnishes can't work, because they lack the reaction of the oil with the rosin, which seems chemically not well understood. Most interestingly, the actual polymerisation happens light induced (I.e. as a photopolymerisation) afterwards on the wood. I could not find any article looking at the chemistry of the monomers and the polymers, nobody seems to know what the chemical compounds are.

Please correct me if I am wrong. I would be interested in any publication that describes the chemistry of these varnishes. To make violin varnishes all this is not needed. But it is a missing piece of information to understand what these old Italian varnishes are.

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