Stradivari's golden ground varnish


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3 hours ago, MikeC said:

 

Properties of the ground has been described by some as very resistant to solvents, on the other hand some time ago on another thread there was mentioned that a Strad had been set down on an alcohol rag that was used to clean strings and when lifted, the ground had been removed down to bare wood.  So is it solvent resistant or not?

The ground appeared to have been removed down to the bare wood, but I can't say for sure, since I didn't try to dig beneath what remained to see if there might have been further strata. The player didn't own the Strad, and the request was to make the phuckup disappear in 48 hours, so no-one would know.

At the time, this was a very pristine Strad, and the area where the varnish came away on the rag still seemed to be all-original, unlike most Strads today. and unlike that particular instrument today. Today, I can't even recognize the instrument as the one I once worked on. Such are the ravages of overuse, versus museum environments.

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2 hours ago, MikeC said:

After enough time LO becomes alcohol soluble as seen in Sora's five year old linoxin used as a component in varnish. .   I had a sample of thirty year old LO that looked and behaved exactly as his,  unfortunately not enough to use for varnish making.  

Will it change when still in bottle? My bottle is just over 20 years old...

My maple scrap tests looked much like AD's. My oil is just cooked with lead dryers. Slightly thicker than raw. Virtually every old woodworking book (60 years or older) here suggest layers of "linseed oil varnish" as base on raw wood  before painting. In this case the "linseed oil varnish" is product called "fermež" here and still produced by local companies (they have produced it forever) and sold in most paint stores - it is basically boiled linseed oil cooked for slightly thicker consistency and it tends to suck oxygen from the soft plastic bottles it is sold in and any spills get rubbery over night or two. It was also used by old school plumbers for sealing steel tubing threaded connections together with hemp fibers (before the teflon tape or floss came to market). No bottle ever showed contents other than "fermež ľanová" which loosely translates into "linseed oil varnish" but it is certainly not varnish it tends to soak in if applied heavily (or diluted with naphtha or similar as sometimes suggested) but n thin application it stays mostly on top surface...

I will make some fresh samples when I get out of this CORONA prison...

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3 hours ago, MikeC said:

Some thoughts after reading all this.  From Echard it's only oil,  from B&G it may have some resin content.  Some of you are concerned about oil penetration but that has been demonstrated not to be an issue.  But if it is a concern then B&G also detected protein which could be a sealer to prevent penetration of oil.  Davide Sora in one of his videos shows application of a dilute casein as a sealer.  So finishing steps,  first apply a dilute protein sealer if you think it's needed to prevent oil penetration, then apply whatever stain then LO or uncolored varnish then colored varnish. Why would Strad and the others use plain LO rather than uncolored varnish? presumably they would have had both available. 

Properties of the ground has been described by some as very resistant to solvents, on the other hand some time ago on another thread there was mentioned that a Strad had been set down on an alcohol rag that was used to clean strings and when lifted, the ground had been removed down to bare wood.  So is it solvent resistant or not?

  After enough time LO becomes alcohol soluble as seen in Sora's five year old linoxin used as a component in varnish. .   I had a sample of thirty year old LO that looked and behaved exactly as his,  unfortunately not enough to use for varnish making.  

My questions remain,  are the old grounds solvent resistant or not? is it just LO or uncolored varnish?  Are the old grounds really all that golden yellow or does that apparent color come from later over coats of polish? 

Excuse all these random thoughts.. I'm just thinking ahead to the finishing process on my current VSO build.  :) 

 

Penetration of the wood by linseed oil IS a concern. If you apply a lot, it will soak it up like a sponge. This was Michelman's mistake and most likelyis the reason why oil ground got bad reputation. Stradivari may have had only half a gram of oil in the spruce belly of his violins and maybe the same amount on top.

I am skeptical of the claims about casein, I think there may be some confirmation bias going on there.

I also don't think applying stain is a good idea. The oil itself gives a golden glow, but in my opinion, stain applied to the wood is not a good look.

The story about the ground being removed on Strad by being placed on a rag? That was probably Shellac removed by alcohol don't you think?

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25 minutes ago, sospiri said:

The story about the ground being removed on Strad by being placed on a rag? That was probably Shellac removed by alcohol don't you think?

No, this was not my impression. And shellac tends to be less soluble in alcohol over time, though much depends on how shellac is harvested and processed. Shellac properties can be all over the map.

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2 hours ago, David Burgess said:

No, this was not my impression. And shellac tends to be less soluble in alcohol over time, though much depends on how shellac is harvested and processed. Shellac properties can be all over the map.

I tested the original question before I asked mine. I found that if I rubbed one oil ground  plate with alcohol, some of the oil was removed, but not on another which was oil plus rosin.

Conclusion: It's a good question.

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11 hours ago, Advocatus Diaboli said:

Echard is the one who’s repeatedly found what appears to be linseed oil in the first few Cell layers, presumably as a ground. 

I think the Echard paper you are referring to is the Angewant chemie paper of 2009 where he looks at the Provigny violin varnish at the wood, lower layer, and upper layer--this is Figure 2. (you should all look at it)  This is the FTIR spectra.  The important region is at 1725 to 1715 wave numbers where he makes a conclusion that an oxidized oil  is in the wood.  This peak is at 1714 wave numbers  in the varnish region and 1720 in the wood.  There are only 6 wave numbers difference between what is in the wood (and he calls an oil) and the upper layer  (which he calls a varnish).   I think this is too close to make such a definitive statement about oil in the wood as a ground.  FTIR spectra are not that definitive.

What I am saying is this is not adequate evidence to set makers on the path of putting oil into the bare wood as a ground.

Mike D

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14 hours ago, Advocatus Diaboli said:

 If we’re worrying about compounds in the wood, I’d be a lot more worried about salt from sweat than I would be drying oils.  I suspect most, if not all violins have sweat from the maker in the wood, but not enough to really affect anything. 

I smell another "Secret of Stradivari" theory...

2 hours ago, Mike_Danielson said:

There are only 6 wave numbers difference between what is in the wood (and he calls an oil) and the upper layer  (which he calls a varnish).   I think this is too close to make such a definitive statement about oil in the wood as a ground.  FTIR spectra are not that definitive.

What I am saying is this is not adequate evidence to set makers on the path of putting oil into the bare wood as a ground.

Is it adequate evidence that they didn't use linseed oil that way?

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2 hours ago, Mike_Danielson said:

I think the Echard paper you are referring to is the Angewant chemie paper of 2009 where he looks at the Provigny violin varnish at the wood, lower layer, and upper layer--this is Figure 2. (you should all look at it)  This is the FTIR spectra.  The important region is at 1725 to 1715 wave numbers where he makes a conclusion that an oxidized oil  is in the wood.  This peak is at 1714 wave numbers  in the varnish region and 1720 in the wood.  There are only 6 wave numbers difference between what is in the wood (and he calls an oil) and the upper layer  (which he calls a varnish).   I think this is too close to make such a definitive statement about oil in the wood as a ground.  FTIR spectra are not that definitive.

What I am saying is this is not adequate evidence to set makers on the path of putting oil into the bare wood as a ground.

Mike D

The oil ground hypothesis has been around for what? 200 years?

Maybe he his research conclusion is confirmation bias, but I found his research after several other sources of the same hypothesis before I attempted it. The fact that people don't take it seriously is something I see as a prejudice based on misinformation.

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What would prevent someone from using egg white /glair or other protein base as a pore filler, and wiping off the excess on the surface with a damp rag? This should leave the pores filled and yet leave the raw wood still open enough for a ground varnish of close RI to enhance the wood figure.

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2 hours ago, Mike_Danielson said:

I think the Echard paper you are referring to is the Angewant chemie paper of 2009 where he looks at the Provigny violin varnish at the wood, lower layer, and upper layer--this is Figure 2. (you should all look at it)  This is the FTIR spectra.  The important region is at 1725 to 1715 wave numbers where he makes a conclusion that an oxidized oil  is in the wood.  This peak is at 1714 wave numbers  in the varnish region and 1720 in the wood.  There are only 6 wave numbers difference between what is in the wood (and he calls an oil) and the upper layer  (which he calls a varnish).   I think this is too close to make such a definitive statement about oil in the wood as a ground.  FTIR spectra are not that definitive.

What I am saying is this is not adequate evidence to set makers on the path of putting oil into the bare wood as a ground.

Mike D

Let me add that I believe there is a third organic source that Echard overlooked, namely the organic colored stain. If I am right, this mistake leads to overestimating the presence of linseed oil. I believe that if the organic stain’s contribution to this FTIR spectral region is what I think it is, Echard was looking at something with a lot more rosin, namely a varnish which will agree with Brandmair’s findings.

 

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50 minutes ago, Michael_Molnar said:

Let me add that I believe there is a third organic source that Echard overlooked, namely the organic colored stain. If I am right, this mistake leads to overestimating the presence of linseed oil. I believe that if the organic stain’s contribution to this FTIR spectral region is what I think it is, Echard was looking at something with a lot more rosin, namely a varnish which will agree with Brandmair’s findings.

 

That’s not very helpful if you aren’t sharing what you think the stain is.  

Echard has done much more research since his 2009 paper, and although to my understanding his findings have evolved slightly, there aren’t any significant changes in the findings.  I know John Harte and maybe others have been in touch with him and other researchers.  I’d love to hear what they have to add.  
 

 

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A test...

Small drops of various varnishes and oils applied to white paper, and then hung vertically... one in darkness, one in the UV cabinet.  The first iteration showed a small spread of the linseed in UV, which I thought might be related to the size of the drop (not controlled) vs. the UV effect, so I repeated the test with a larger (apparently MUCH larger) drop immediately below it.

My conclusion:  the straight oils have such low viscosity and slow polymerization that they spread like mad before the UV can have an effect.  The thicker varnishes have a much lower spread/polymerization ratio. I think the tung oil is slightly thicker than the linseed, too.

1618175666_Spreadingtest201227.jpg.b8b5393bf42703915df14330393417c5.jpg

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4 hours ago, Mike_Danielson said:

I think the Echard paper you are referring to is the Angewant chemie paper of 2009 where he looks at the Provigny violin varnish at the wood, lower layer, and upper layer--this is Figure 2. (you should all look at it)  This is the FTIR spectra.  The important region is at 1725 to 1715 wave numbers where he makes a conclusion that an oxidized oil  is in the wood.  This peak is at 1714 wave numbers  in the varnish region and 1720 in the wood.  There are only 6 wave numbers difference between what is in the wood (and he calls an oil) and the upper layer  (which he calls a varnish).   I think this is too close to make such a definitive statement about oil in the wood as a ground.  FTIR spectra are not that definitive.

What I am saying is this is not adequate evidence to set makers on the path of putting oil into the bare wood as a ground.

Mike D

 

27 minutes ago, Advocatus Diaboli said:

That’s not very helpful if you aren’t sharing what you think the stain is.  

Echard has done much more research since his 2009 paper, and although to my understanding his findings have evolved slightly, there aren’t any significant changes in the findings.  I know John Harte and maybe others have been in touch with him and other researchers.  I’d love to hear what they have to add.  
 

 

Actually, there is probably more than one organic stain that shares the 1720 cm-1 region, so citing my candidate is not necessary. The reason I am quiet about it is that I am making test samples for an unbiased expert to review. I find that there are many ways to prepare this stain and they can give different results. Of course, I am focusing on those processes that look like what I see on Strad’s. I found that trace metals can shift the color. Other parameters control stability.  The big reason I am quiet is that as with all organic stains the preparation and application determine the outcome. So, in the hands of the uninitiated, the results would likely come out wrong and then no one would accept what I have before I can present my findings. Keep in mind that my candidate may fall flat on its face. 

So, stay tuned.

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8 hours ago, Don Noon said:

A test...

Small drops of various varnishes and oils applied to white paper, and then hung vertically... one in darkness, one in the UV cabinet.  The first iteration showed a small spread of the linseed in UV, which I thought might be related to the size of the drop (not controlled) vs. the UV effect, so I repeated the test with a larger (apparently MUCH larger) drop immediately below it.

My conclusion:  the straight oils have such low viscosity and slow polymerization that they spread like mad before the UV can have an effect.  The thicker varnishes have a much lower spread/polymerization ratio. I think the tung oil is slightly thicker than the linseed, too.

But paper is not wood... try to wipe a drop of oil from your table with a wood shaving and piece of paper. Paper wins every time.

Teh microscopic structure of paper is completely different and so is its absorbtion of liquids.

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47 minutes ago, HoGo said:

But paper is not wood... try to wipe a drop of oil from your table with a wood shaving and piece of paper. Paper wins every time.

Teh microscopic structure of paper is completely different and so is its absorbtion of liquids.

The process of applying linseed oil directly to the wood is quite simple. A very small amount which soaks in quickly, and when rubbed it comes back to the surface. You just run till it's dry and the wood is sealed with a very small amount. 

I don't use a UV box, it's a complete red herring fro this process, as is strong direct sunshine. It makes no difference.

I've told Don and Michael this many times, but at some point one has to realise they have their own agenda. 

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Casein (In the form of fresh cheese curd) and slaked lime makes an emulsion that you can add a little linseed oil and/or varnish to. There is a lot of possibilities. Applying it on tanned wood gives an instant reaction of golden old wood look. Intensity is depending on the mix (ph level) and how much tanning. Combined with some colored varnish it's possible to get a quite dark ground that is not stained.

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3 hours ago, sospiri said:

...at some point one has to realise they have their own agenda. 

It seems obvious by now that there are infinite possibilities... and how many of the posts so far recommend the same thing?  I think everyone ends up with a different set of materials and processes... and so far, I think  every instrument I've made has been a bit of an experiment in varnishing.  

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1 minute ago, Don Noon said:

It seems obvious by now that there are infinite possibilities... and how many of the posts so far recommend the same thing?  I think everyone ends up with a different set of materials and processes... and so far, I think  every instrument I've made has been a bit of an experiment in varnishing.  

Yes endless possibilities. But Strad's golden ground was probably a tradition that other Cremonese masters used. 

I agree with your point about the patina on a 450 year old instrument.

 

 

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34 minutes ago, sospiri said:

I agree with your point about the patina on a 450 year old instrument.

I think of "patina" as a surface effect, but age does things to wood and varnish throughout its thickness as well.  Old instrument wood is known to be opaque, new wood (and even 300 year old wood cut from a building beam) is not.  And what happens to the color of clear varnish or linseed oil over 300+ years... or whatever ground Strad used?  Strad used fresh wood (relatively), fresh varnish, and made new instruments that nobody know how they looked.  So, for me it is moot what Strad used for his "golden ground", as it is virtually certain that the golden result we see today is not what it looked like when it left the shop.

And as a new instrument maker, what it looks like new is what matters.

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24 minutes ago, Don Noon said:

I think of "patina" as a surface effect, but age does things to wood and varnish throughout its thickness as well.  Old instrument wood is known to be opaque, new wood (and even 300 year old wood cut from a building beam) is not.  And what happens to the color of clear varnish or linseed oil over 300+ years... or whatever ground Strad used?  Strad used fresh wood (relatively), fresh varnish, and made new instruments that nobody know how they looked.  So, for me it is moot what Strad used for his "golden ground", as it is virtually certain that the golden result we see today is not what it looked like when it left the shop.

And as a new instrument maker, what it looks like new is what matters.

I'm not a fan of antiqueing, but like many, I am a sucker for a nice patina.

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6 hours ago, Michael_Molnar said:

The lists are tables in B&G.

 

I don't have the book, have never read it and can't imagine I ever would want to own it. Is the list even important in any way that would be meaningful to me?

I just read the entire Nagyvary review thread and the protein sealer idea is not taken seriously. It doesn't seem to be Brandmair's idea, rather Greiner's. What is your impression?

And why do you dismiss Echard's work? Because you tried it once and didn't like it? That's normal I'm sure, because it is easy to apply too much.

I should point out that I didn't learn about his research until after reading the same idea from another source published in 1973,  who quoted a source from 100 years before that. Then finding a violin with an oil ground that had a unique sound, despite being rather crudely made.  

To get what I wanted required an awful lot of practice. It wasn't just some quirky idea that I had to follow.

One poster on that thread summed up most of my ideas in their own way. This is a common goal, not just of aesthetics. What you put on the instrument is very important to the player, and how the instrument responds to their touch. Otherwise the best sounding instruments would be unvarnished. 

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