Iron Rosinate

[Christopher Jacoby]

Sospiri, if you're not cooking anything, you're not ever going to understand what varnish does sound good, and why. 

and I stand by my assertion that what the wood gets, and how, before the pores are sealed off, more or less, is what determines sound MORE than subsequent layers. The rest is fun. Thickness of varnish determines sound far more than materials, and shellac ain't bad for sound. Lacs can also be handled a hundred ways, and can't be blanketed as one thing or another...

[uguntde]

On 22/03/2017 at 5:23 PM, sospiri said:

Davide, indeed, how many variations on 'spirit varnish' and 'oil varnish' are there? And how many people claiming their introduction of linseed oil to their 'spirit varnish' makes it a good alternative to 'linseed oil varnish'?

Contless thousands I guess is a general answer to all three questions?

I sit dumbfounded reading the recipes some people give and wonder which alchemical tomes influenced them?

I want to keep it simple, especially so since I am searching for something (possibly imaginary) I consider a good old sound and finish that has been around for hundreds of years, but has been largely replaced by more recent methods.

Didn't the 'Cremonese varnish' die out gradually from the early 18th century onwards due to the introduction of different methods?

I don't doubt that many people love the sound of certain spirit varnish instruments, it's part of their memory and emotions.

Many of the early 20th century Italian makers (Bisiach, Fiorini, Poggi) used spirit and not oil varnish, and many of their instruments have an excellent sound.   personally prefer the looks of a good spirit over oil varnish. I see the preference for oil varnishes just as a kind of fashion in modern violin making.

[sospiri]

21 hours ago, James M. Jones said:

Don't want to derail Don's thread. ...but....

Sosperi ,Sounds like you like to "play" with ideas and techniques ....so do I . As I get older though, I find myself " hedging my bets" more and more as a means to achieving (at least in my little grey head) a better success to failure ratio. Have you tried any experiments to determine the tonal qualities imparted by Raw linseed oil? I found that the base line freq of a given slab dropped through the floor,as did sustain. and never seemed to recover. Raw linseed oil will never get sturdy and hard.May seem dry ....but it's not hard. Damping might be good in a violin . however much of that is produced in the arching , materials and overall shape from the start, Visually linseed oil is top of the line....but acoustically...not so good.Of course that is subjective..... so is the visual aspect.

  Bow  Rosin , is not just rosin,Different parent species of tree have different chemical components, these components affect the working qualities. After that, the rosin has been cooked down ,mixed up,added to, turned around and cooked down again. These different mixes are used to achieve differing qualities at the string. less cooking roughly translates to more grab, good for a bass, maybe to much for a violin. Used without oil as a top cote pure rosin will bleed white when scratched, melt in the hand (if a soft resin) and Chip off if too hard. Let's face it ...IF thousands of the worlds smartest people have been trying for hundreds of years to recreate "Strads" varnish.... ????.....As they say " details"

  Personally ,I'm of the philosophy that defining goals becomes a key tool in defining the path. 

    Don, beautiful work, as always, glad your here.

Now ....back to "Iron Rosinate".

 

Yes James, it's called experimenting. I'm searching for sounds and I like what I'm hearing. I could experiment for years and not get that couldn't I?

[sospiri]

21 hours ago, martin swan said:

This is not "varnishing a violin" so much as spreading a load of goo on it.

If you are conducting tonal experiments, that's all well and good, but there's no point in a tonally excellent varnish (which bestows on your Saxon VSO the sound of Fritz Kreisler) unless it also protects the violin and is stable and durable.

It's not goo Martin. I'll show you some day. I might even let you play it, but nor for too long.

[sospiri]

18 hours ago, Christopher Jacoby said:

Sospiri, if you're not cooking anything, you're not ever going to understand what varnish does sound good, and why. 

and I stand by my assertion that what the wood gets, and how, before the pores are sealed off, more or less, is what determines sound MORE than subsequent layers. The rest is fun. Thickness of varnish determines sound far more than materials, and shellac ain't bad for sound. Lacs can also be handled a hundred ways, and can't be blanketed as one thing or another...

Christopher, I'm not cooking because I think it's a red herring. I agree with your second point. I'm keeping it super thin. I will try a thin shellac, but I think that I have achieved a resilience, a suppleness, which increases the range of sounds available. Can I get that with lacs? I will try.

[sospiri]

14 hours ago, uguntde said:

Many of the early 20th century Italian makers (Bisiach, Fiorini, Poggi) used spirit and not oil varnish, and many of their instruments have an excellent sound.   personally prefer the looks of a good spirit over oil varnish. I see the preference for oil varnishes just as a kind of fashion in modern violin making.

Thanks uguntde I understand your points.

[franciscus]

1 hour ago, sospiri said:

it's called experimenting

Yes, but up to the primary school. After that, it's called playing or maybe "shooting in the dark". Serious adults approach to the experiment after absolving the "History and Theory" part.

[sospiri]

Just now, franciscus said:

Yes, but up to the primary school. After that, it's called playing or maybe "shooting in the dark". Serious adults approach to the experiment after absolving the "History and Theory" part.

Back to Iron Rosinate.

[franciscus]

1 hour ago, sospiri said:

Back to Iron Rosinate.

With or without cooking?

[Michael_Molnar]

8 hours ago, franciscus said:

With or without cooking?

I haven't tried to cook it - yet. (It's still too cold here in NJ.) This is on my "to-do" list. However, a sample of iron rosinate on wood withstood about 4 days in my UV cabinet which is a good test for fugitive substances. Most fugitive colorants fade on the second day in this "torture chamber" as it were.

[JacksonMaberry]

Don, your results speak for themselves. It seems Michelman was assembling his varnish cold, but you do not. You mention holding at temp for half an hour or so, but what isn't clear is your order of operations, so to speak. Do you put the rosinate, turpentine, and raw linseed into the vessel cold and then raise the temp, or something else? 

[Don Noon]

I cook it like I do with a normal varnish... oil and resin in the pot, cook it to melt everything together (hopefully), and add thinners on cooldown.

[JacksonMaberry]

49 minutes ago, Don Noon said:

I cook it like I do with a normal varnish... oil and resin in the pot, cook it to melt everything together (hopefully), and add thinners on cooldown.

Understood. Thanks very much.

[violins88]

On 2/2/2017 at 8:36 AM, Luis Martins said:

Some theory regarding the crystallization of amorphous iron oxide nanoparticles

The precipitation method in this paper is quite different but results in smaller particles than the chemical precipitation.

It may suggest that iron oxide may crystallize to some form of hematite during the cooking process of the iron precipitate with the organic compounds (cooking the varnish), turning the resulting Fe into a non reactive, stable ovoid shaped crystal. But it will need time and temperature. Some studies say 400h@100C. Increasing temperature should decrease time.

It may also contribute to some iridescence in the varnish since crystallized iron flakes diffract light.

If Fe does in fact crystallize in the process of cooking the varnish, it would take trace amounts of Fe to produce real results, something like 0,5 to 1%

I have new powder samples of nano oxides from China. You have stimulated me to try to mull them into varnish.

The oxides that are pre-mulled are very transparent, but the carrier liquid inhibits varnish drying. I have asked them to solve this.

[Andreas Preuss]

No matter how we look on all varnish reasearch, it always just opens a very small window of the truth. IMO, research gives only solid indicators to what we can exclude from our shopping list of ingredients. The rest is upon our own interpretation to make a recipe from it.

Concerning the Michelman color varnish I never followed the recipe but rather used the idea which is pretty simple: Take rosin dissolve it in alkaline solution add alum to fix it, filter it and when still wet you can add alcohol dissolved alizarine to the paste to make the desired color. I add Turpentine when still wet, which saves me later the time to grind the powder. (In fact I never used a glass plate and a muller) This is a bit messy but with long continuing cooking below the evaporation temperature of turpentine you can drive out the water to get a nice color paste. (if you have the time, you just can place the turpentine water paste at a sunny window for 3-4 weeks adding every now and then a bit turpentine) This paste can be blended easily with any turpentine oil varnish or used just without blending into another varnish.

One variations of this procedure is to extract the madder root colorant in the hot alum solution or cook it with the rosin in the alkaline solution. with other dyestuff you might get other ideas what works best.

Another variation is to add iron sulfate to the alum. this makes without dyestuff a browner hue, depending on how much you add. I never tried to make a varnish with using only iron sulfate, because I never came close enough to the characteristic brick red color in classical Cremonese varnishes. If you use dyestuff later it can be dangerous to use too much iron because most colors loose their brilliancy and turn too brown. If any I am adding not more than 1% weight volume to 100% of alum to have a darker shading. But I suspect that those quantities of iron came from iron pots used in the days of Stradiari.

Finally a word about colorants in Strads varnish: Just judging from the look I would say he used other dyestuff on cellos than on violins. Cellos have a less transparent thicker varnish and I suspect, because alizarine and cochineal colorants might have been expensive, he replaced them with cheaper less transparent earth pigments.

 

[D. Piolle]

On 2/3/2017 at 4:42 PM, joerobson said:

Is positively identified as cochineal.....

on we go,

Joe

 

On 2/3/2017 at 6:54 PM, Davide Sora said:

Yes,  I know that cochineal is the more frequently found pigment, but I agree with Greiner and Brandmair that the little quantity dos not make the main color of the colored varnish, I don't remember Echard thoughts in this regard.

Cochineals need a substrate ( metal salt, usually alum... ) to be fixed and make the pigment and starting from the same cochineal but with a different substrate might give different colour results.

[uguntde]

On 3/20/2017 at 12:43 AM, Don Noon said:

Not a good idea to post any photos directly after Melvin's, but here's my first full-fiddle use of iron rosinate in linseed oil.  I added quite a bit of Gilsonite to brown down the red of the iron rosinate (intent was to get a brownish result).  So far, I'm very happy with this varnish, even if the antiquing needs some improvement, and it definitely doesn't look Cremonese under UV.

Was this varnish made by cooking linseed oil and rosin or using the Michelman method? It looks nice. I think I prefer the smoother transitinos between no color and color in Carl's violin, but then I prefer the iron red.

Does anyone use a good spirit varnish?

 

[uguntde]

On 2/4/2017 at 3:59 PM, Michael_Molnar said:

Please. We need to be a bit more precise about what we are saying. First of all, terms like iron chloride or iron sulfate are ambiguous and misleading. There is a world of difference between ferric chloride and ferrous chloride. The same holds for ferric sulfate and ferrous sulfate.  They produce different colors.

Second. My interpretation of B&G and Echard point to cochineal in the 4th layer of B&G's model much like a glaze. You can see this in the wear patterns. Unworn areas lean toward magenta while worn areas are dark red, a very different hue. Cochineal, however, was not always used by Stradivari. As Brandmair suggested, their book should be titled Stradivari's Varnishes. I like cochineal a lot for its magenta hue that I often see in the top layer. I believe Hargrave leaned towards lac which is related to cochineal. They are anthraquinone cousins.My point of clarification is that Strad et al. had more than one source of red in their systems of varnish layers. To my eyes, the red (magenta) glaze sits over other red (orange-red) sources, perhaps ferric pigments or rosinates (or linoleates). The list is long.

 

Which one do you use? Ferric or ferrous chloride? In chemical terms it is Fe3+ vs Fe2+, the former is yellow-red, the latter green. Fe3+ complexes are usually red. But under varnish cooking conditions it shouldn't matter, because heat and oxygen will convert Fe2+ into Fe3+.

 

 

[Michael_Molnar]

2 hours ago, uguntde said:

Which one do you use? Ferric or ferrous chloride? In chemical terms it is Fe3+ vs Fe2+, the former is yellow-red, the latter green. Fe3+ complexes are usually red. But under varnish cooking conditions it shouldn't matter, because heat and oxygen will convert Fe2+ into Fe3+.

 

 

I now avoid working with iron salts of any oxidation state.*  If I use iron, it is in a stable earth pigment or lab-made (nano) oxide. The potential problem with iron is that it can switch states and color. Often red rust will darken in linseed oil to become black. The most unstable form of iron comes from iron pots used for cooking: The lovely red darkens over time. According to artists, the chemical activity of linseed oil accelerates this metamorphosis. 

* I apologize for any past threads in which I confused ferric (+3) and ferrous (+2). 

[Michael_Molnar]

4 hours ago, D. Piolle said:

 

Cochineals need a substrate ( metal salt, usually alum... ) to be fixed and make the pigment and starting from the same cochineal but with a different substrate might give different colour results.

Right. This is discussed in Michelman's book here . 

[JacksonMaberry]

Michelman also seemed a bit more enthusiastic about the cochineal zinc rosinate than the aluminum. 

[Andreas Preuss]

From an historic perspective I don't think the cochineal dyestuff in the varnish was an unaltered recipe over the span of 30-40 years. The main source for cochineal seemed to have been Mexico. (Or at least not in Europe) In a time where everything had to be transported by ship and horse carts this stuff must have had a pretty hefty price tag. (Sometimes I wonder really HOW expensive it was) And in times where Cremona was just in the middle of Austrian and Spanish and French armies fighting against each other, I doubt that this stuff was easliy and cheaply available. This makes me rather think that, whoever made the varnish, he had a certain color hue in mind he would produce with whatever materials were available.

 

[Andreas Preuss]

4 hours ago, uguntde said:

Does anyone use a good spirit varnish?

Joachim Schade is to my knowledge the only copyist who could get dammed close to the Cremonese varnish using a spirit varnish. I have seen some of his golden period instruments when I was still younger and less experienced. At that time I really had to think and look and examine for more than 15 minutes to find out that I was holding a copy in my hands (because I figured that an original would have some repairs somewhere.)

[Andreas Preuss]

4 hours ago, uguntde said:

the red of the iron rosinate

Which iron salt did you use? Iron sulphate?

I always got frustrated with using iron salts or pigments. Either too brown or not transparent enough.

[JacksonMaberry]

18 minutes ago, Andreas Preuss said:

From an historic perspective I don't think the cochineal dyestuff in the varnish was an unaltered recipe over the span of 30-40 years. The main source for cochineal seemed to have been Mexico. (Or at least not in Europe) In a time where everything had to be transported by ship and horse carts this stuff must have had a pretty hefty price tag. (Sometimes I wonder really HOW expensive it was) And in times where Cremona was just in the middle of Austrian and Spanish and French armies fighting against each other, I doubt that this stuff was easliy and cheaply available. This makes me rather think that, whoever made the varnish, he had a certain color hue in mind he would produce with whatever materials were available.

 

Perhaps not cochineal, but lac dye instead - the chemical is extremely similar. This would have been more readily available by land or sea trade with Asia. 

Didn't Cremona have a thriving textile industry? I would expect that would attract pigments of all kinds.