Is a hard varnish really bad for the sound?

[Andreas Preuss]

I guess all depends on the thickness of a hard varnish. My thought is simply that if we have a choice between a soft varnish and a hard varnish assuming that both have the same thickness, the hard varnish would be the better choice.

Looking back on what has been promoted in the past, soft varnish was regarded for long time the better choice. (Pure propolis and other strange recipes, all claiming to have rediscovered something)  The argument was mostly that a hard varnish would prevent vibrations while an elastic film wouldn’t do that. However considering the thickness of the varnish in proportion to the thickness of the wooden plate underneath, I think it is just a misleading argument. I would rather argue that a rubbery substance on a wooden surface dampens most likely frequencies somewhere in the higher registers. (?) So wouldn’t it be better to aim for a varnish which is actually rather ‘glass like’? This includes also the thought that a somehow thicker coat of a hard varnish does less harm than a thicker coat of soft varnish. 
 

PS: Regarding the positive effects of damping as discussed in a recent thread, I am wondering if it is a good idea to achieve it with the varnish.

[Claudio Rampini]

Is it yours a theoretical or practical problem? a hard or rubbery varnish is not the right thing, but an elastic and slightly thermoplastic one is good.

[HoGo]

I wonder how you measure hardness of given finish and what thickness we are talking about and on what instrument?

If you consider 0.5 mm thick finish on reasonably built fiddle then I guess soft finish will hurt it less than hard one (like epoxy floor finishes) but if the fiddle is seroiusly underbuilt then the 0.5mm layer of harder finish may make it a bit closer to acceptable while soft goo would just kill it.

On mandolins pretty much any type of finish works when its thickness is kept within reasonable limits. Of course some durability is expected so rubbery finishes are ruled out.

[christian bayon]

I never had this feeling. I have been using amber varnish for many years. Amber is very hard, good resistance to wear. I don’t think it made sounds problem.

[ernym]

17 hours ago, christian bayon said:

I never had this feeling. I have been using amber varnish for many years. Amber is very hard, good resistance to wear. I don’t think it made sounds problem.

I also use amber varnish and feel the same about the durability. I buy two commercial amber varnishes rather than make it.  One is leaner than the other so I modify it by combining them adjusting the oil/resin ratio. Then tested on samples until the cured varnish is not too hard or soft. To this varnish I can add highly colored coats by adding rosinates and/or pigments keeping the final film thickness thin. Alot depends on first getting the right ground color into the wood.

[Andreas Preuss]

9 hours ago, Claudio Rampini said:

Is it yours a theoretical or practical problem? a hard or rubbery varnish is not the right thing, but an elastic and slightly thermoplastic one is good.

My question was more theoretical. What sort of general idea should leading us for a good varnish coating? I wanted to hear some ideas based on experience. Or someone who could pin down with positive proof the negative effect of a hard varnish. 
 

I would say, if we were able to peel down the complete varnish like a hull of an insect which becomes a butterfly and would compare the elasticity of a ‘hard’ varnish and an ‘elastic’ varnish the difference would be minimal. 
 

Besides, I think violin expert Charles Beare made long ago the shocking experience that the entire varnish on the top of a fine sounding Stradivari was as a matter of fact all shellack touch up with probably only tiny islands of original varnish left.
 

 

[Andreas Preuss]

9 hours ago, HoGo said:

I wonder how you measure hardness of given finish and what thickness we are talking about and on what instrument?

The hardness is roughly determined (estimated) by the main resinous components, just as painters categorize ‘dammar’ as a soft varnish and ‘copal’ as a hard varnish.

 

9 hours ago, HoGo said:

If you consider 0.5 mm thick finish on reasonably built fiddle then I guess soft finish will hurt it less than hard one (like epoxy floor finishes) .

That’s the question. I understand what you are saying more theoretical, as there is probably no varnish as thick as 0.5mm

My unscientific view is that we need to understand which frequencies are affected by which coating. While a hard coating could affect slower vibrations obstructing larger surfaces to bend, I would estimate that a soft coating does the opposite. So one would largely speaking have an effect on signature modes, the other more on high frequencies or overtones. 

10 hours ago, HoGo said:

On mandolins pretty much any type of finish works when its thickness is kept within reasonable limits. Of course some durability is expected so rubbery finishes are ruled out.

On the practical side it seems that whatever you choose the philosophy of ‘ the thinner the better’. At least when I first was doing touch up jobs on famed Cremonese instruments I realized that the varnish thickness was ‘almost nothing’ despite its color intensity. 

[Andreas Preuss]

10 hours ago, christian bayon said:

I never had this feeling. I have been using amber varnish for many years. Amber is very hard, good resistance to wear. I don’t think it made sounds problem.

Actually I used for my copies also amber varnish. My rough guess is that a varnish even harder than amber wouldn’t harm. 

[Victor Roman]

13 hours ago, Andreas Preuss said:

I guess all depends on the thickness of a hard varnish. My thought is simply that if we have a choice between a soft varnish and a hard varnish assuming that both have the same thickness, the hard varnish would be the better choice.

Looking back on what has been promoted in the past, soft varnish was regarded for long time the better choice. (Pure propolis and other strange recipes, all claiming to have rediscovered something)  The argument was mostly that a hard varnish would prevent vibrations while an elastic film wouldn’t do that. However considering the thickness of the varnish in proportion to the thickness of the wooden plate underneath, I think it is just a misleading argument. I would rather argue that a rubbery substance on a wooden surface dampens most likely frequencies somewhere in the higher registers. (?) So wouldn’t it be better to aim for a varnish which is actually rather ‘glass like’? This includes also the thought that a somehow thicker coat of a hard varnish does less harm than a thicker coat of soft varnish. 
 

PS: Regarding the positive effects of damping as discussed in a recent thread, I am wondering if it is a good idea to achieve it with the varnish.

It is an interesting question but it needs qualifying. If you play professionally, in large halls, hard varnish is best. In your bedroom, a soft varnish ( I went through the propolis era.... ) makes the sound more bearable. One thing one does not want and this must be learned, is to accept the tone as heard by the player. Often edgy and noisy - that works well in larger spaces. In the past, when I used to give lessons, I noticed young people were bothered by a proper violin tone and preferred a "sweet" tone, often ( secretly...) using a mute when practicing. That is in mine and others opinion, a grave error. 

Around 1980 I met a wonderful amateur maker who made fairly good albeit not to a high standard of workmanship, violins. He had quite a number under his belt - around 300, I think. Plus a couple of cellos and violas. He varnished everything with shellac + 10% by weight propolis. Good result.

I wish to mention that as a teenager I had the use of a violin ( German ) which has never been varnished. It was OK but the tone was not quite there. The owner took it to a maker who lightly french polished it and the result was very decent.

[Claudio Rampini]

1 hour ago, Andreas Preuss said:

My question was more theoretical. What sort of general idea should leading us for a good varnish coating? I wanted to hear some ideas based on experience. Or someone who could pin down with positive proof the negative effect of a hard varnish. 
 

I would say, if we were able to peel down the complete varnish like a hull of an insect which becomes a butterfly and would compare the elasticity of a ‘hard’ varnish and an ‘elastic’ varnish the difference would be minimal. 
 

Besides, I think violin expert Charles Beare made long ago the shocking experience that the entire varnish on the top of a fine sounding Stradivari was as a matter of fact all shellack touch up with probably only tiny islands of original varnish left.
 

 

Are you testing your violins in white? I have played all my violins in white, and I can hear the difference before and after the varnish, the difference is astonishing. If you don't play your violins in white you'll never know that important difference without and with the varnish. I'm telling you this because the majority of the luthiers don't play their violins in white.

I have used harder and "rubbery" varnishes (my mistakes), and I found that a harder varnish is preferable, but the instrument will be closed in a sort of shiny glass cage, expressing a harsh and penetrant tone. About 20 years ago I found my "magic" oil/sandarac varnish, and I have experimented it on a my old violin previously varnished with a Sacconi 1704 variant, the result was astonishing!

Regarding the Charles Beare's experience, I can confirm that, but in that case we are talking about of "peeled" tops and very tiny shellac layers. The principle remains the same: you can use a hard varnish, but it should be applied in very thin layers, touching up is not varnishing. I remember that Sgarabotto followed this way on his instruments: just a very thin shellac varnish.

Side note: when someone here published a book on the Toscano 1690, there was shellac in their varnish analysis. But the varnish sampling was done under the fingerboard, and you know that the original instruments were not varnished under the fingerboards: the shellac was applied successively to protect the bare wood.

[Christian Pedersen]

.

[Don Noon]

5 hours ago, Claudio Rampini said:

I have played all my violins in white, and I can hear the difference before and after the varnish, the difference is astonishing.

I used to do that, and yes, I heard the distinctive harsh, fuzzy tone in the white.  Much reduceded fuzz and harshness with varnish.  As best I can determine, it is the very high frequencies that are damped down by the varnish.

All varnishes are some kind of organic polymer, and I think they have much higher damping properties than the more crystaline cellulose of the wood (if you could vapor deposit glass, that might be different).  Likewise stiffness/density of the varnish will be a lot lower, and it's the same in all directions as opposed to the wood directionality.  

So, at this point, I think all varnishes do somewhat similar things to tone, and I haven't messed with different varnishes to be positive about it.  I also think individual taste in tone comes into play, so "better" for one ear wouldn't be universal.

My preference would be to have a durable varnish that doesn't wear or turn to goo when the player sweats.  Details of tone I think is in the noise... so to speak.

[Claudio Rampini]

3 hours ago, Don Noon said:

I used to do that, and yes, I heard the distinctive harsh, fuzzy tone in the white.  Much reduceded fuzz and harshness with varnish.  As best I can determine, it is the very high frequencies that are damped down by the varnish.

My violins in white are wild horses, full power and overtones richness, but difficult to control. The varnish make it more controllable, but it should be very thin, for this reason the old oil varnish recipes are the best choice (De Mayerne show a lot of excellent recipes), because you can add just 6/8 grams of varnish in a very thin thickness.

Here my old video where you can listen to my violin in white, the recording cut some tone quality, because live and with an unfinished bridge it produced so many overtones that it was almost hurting our ears.

 

[Andreas Preuss]

10 hours ago, Claudio Rampini said:

Are you testing your violins in white? I have played all my violins in white, and I can hear the difference before and after the varnish, the difference is astonishing. If you don't play your violins in white you'll never know that important difference without and with the varnish. I'm telling you this because the majority of the luthiers don't play their violins in white.

I have used harder and "rubbery" varnishes (my mistakes), and I found that a harder varnish is preferable, but the instrument will be closed in a sort of shiny glass cage, expressing a harsh and penetrant tone. About 20 years ago I found my "magic" oil/sandarac varnish, and I have experimented it on a my old violin previously varnished with a Sacconi 1704 variant, the result was astonishing!

Regarding the Charles Beare's experience, I can confirm that, but in that case we are talking about of "peeled" tops and very tiny shellac layers. The principle remains the same: you can use a hard varnish, but it should be applied in very thin layers, touching up is not varnishing. I remember that Sgarabotto followed this way on his instruments: just a very thin shellac varnish.

Side note: when someone here published a book on the Toscano 1690, there was shellac in their varnish analysis. But the varnish sampling was done under the fingerboard, and you know that the original instruments were not varnished under the fingerboards: the shellac was applied successively to protect the bare wood.

I always set up my violins in the white for a sound test. The reason why I don’t really trust the comparison of the white versus the varnished instrument is that varnishes take time to harden completely. ( Besides against all common opinion I think that alcohol based varnishes need more time to settle completely than a well composed oil varnish.)

However, I learned also that what I thought is ideal for the sound, isn’t ideal for most high profile performers. One of my instruments had a really nasty rough sound and you could hear that in the front rows of a hall. But in the back of the hall the same instrument sounded just ‘perfect’. And since then I am not shocked any more when I get a sort of scratchy sound, rather the opposite. 
 

I think shellack isn’t bad at all, at least sound wise. For me the reasons not to use it are rather in the limitations to color it and the way it wears.

But I see from your experience as well something like ‘rather harder than softer’. Thanks for sharing your thoughts.
 

 

[Victor Roman]

40 minutes ago, Andreas Preuss said:

I always set up my violins in the white for a sound test. The reason why I don’t really trust the comparison of the white versus the varnished instrument is that varnishes take time to harden completely. ( Besides against all common opinion I think that alcohol based varnishes need more time to settle completely than a well composed oil varnish.)

One thing I suggest you look for is that after varnishing the pitch becomes cleaner and clearer i.e. easier to perceive. Also, I think you may be right re. alcohol varnish - it takes time to show it's true colors. By the way, among the violins in my small "collection" is a German one, slightly longer than usual, with a very harsh tone, however very playable. I was told that the harshness is due to the varnish being copal based. Back to my first sentence, as I listen to YT samples of new violins I notice that many of them sound "false". This is a complaint I heard many times in the past and unfortunately I never payed much attention to, having nothing really better to compare.

[HoGo]

I wonder where do old Cremonese instruments sit in your comparisons, that were originally coated with oil varnish but either lost most of it over time (in places even with some wood) and/or it was replaced by significant amounts of retouch varnish /alcohol polish. Do they still count as "oil-varnished tone" even they have more spirit varnish on them now?

And I wonder where linoxin varnish is in these comparisons. I'm kinda doubtful in these areas as I don't believe a bit one can discern type of varnish confidently by playing or even looking at it (unless the maker left some eye catching mistakes that hint which type it is). Just like those wine experts that were unable to discern white wine from red when red color was added.

[Claudio Rampini]

11 hours ago, Claudio Rampini said:

My violins in white are wild horses, full power and overtones richness, but difficult to control. The varnish make it more controllable, but it should be very thin, for this reason the old oil varnish recipes are the best choice (De Mayerne show a lot of excellent recipes), because you can add just 6/8 grams of varnish in a very thin thickness.

Here my old video where you can listen to my violin in white, the recording cut some tone quality, because live and with an unfinished bridge it produced so many overtones that it was almost hurting our ears.

 

Another video where you can see the same violin after varnishing (oil/sandarac), my Guarneri "Alard" model. The reverberation is natural, not artificially added, my videos and recordings are unedited, they are as they came out of the camera. Both videos were recorded with a Nikon D700, just for comparison.

 

[Strad O Various Jr.]

3 hours ago, Claudio Rampini said:

Another video where you can see the same violin after varnishing (oil/sandarac), my Guarneri "Alard" model. The reverberation is natural, not artificially added, my videos and recordings are unedited, they are as they came out of the camera. Both videos were recorded with a Nikon D700, just for comparison.

 

Is the violin out of tune, and that reverb is coming from the room, not the violin

[Claudio Rampini]

1 hour ago, Strad O Various Jr. said:

Is the violin out of tune, and that reverb is coming from the room, not the violin

Yes, I never made a violin with a reverberation inside. 

[Alchemia succini]

The problem is that what we think are soft and flexible resins do not necessarily age that way. I would also include balsams in that category as well. For example, here is my amber balsam diluted with distilled turpentine and applied to veneer. I shelved it and checked it occasionally and noticed nothing unusual, but after ten years or so I looked at it carefully under reflected light and to my surprise noted it had developed craquelure over the entire surface. Another sample compounded with a little oil was still perfect. As I've said before, no, this obscure preparation can't be put forward as the true Cremona varnish, but would be my choice for the "Spigelhars" ("mirror resin") of the Van Eycks.

I abandoned the amber varnish theory years ago after I became convinced after much testing that the sealer/ground, and not varnish, was the reason for the beauty and tone of the Italian instruments. I just mentioned Sacconi in a previous post and I believe he came to this same conclusion.

However, I would say a varnish with a hard resin, a minimum of oil, and containing a permanent softener/plasticizer is my choice. Note my emphasis; things like camphor and essential oils, as old motion picture film proves, are only temporary. For instance, I suspect— but can't prove— that when commercial amber varnish was produced in Germany until the war, that it was usually of the short to very (very) short oil type to which was added a tiny amount of a semi-drying oil. In fact, the American varnish chemist Dr. Sabin was amazed at how little oil the continental European varnish makers used, suggesting that they could almost be considered spirit varnishes.

So, I suppose I'm suggesting that rather than use a soft resin bringing its own defects, the inherent shortcomings of a hard varnish can be mitigated by tempering its hardness.

Otherwise, I can only offer what I think may have been the real secret of the fabled coachmaker's varnish after reading what Dr. Laurie suggested was their process: not a copal oil varnish, but rather by applying its components separately, layers of spirit varnish (over matte color) and then topping with "an oil copal varnish," which would have excellent durability. Perhaps this method would achieve our goals here too?

I agree with Claudio though about sandarac varnish. If I were to do it over again today, I would choose sandarac over amber because it has a documented history in the old Italian literature, whereas amber is only to be found here and there and at a later date.

Speaking of this, I'm trying to pull my notes together to start a thread on the varnishes of Dr. Fioravanti, especially his sandarac varnish. An Italian doctor and surgeon (first successful splenectomy; one of the fathers of plastic surgery) he wrote (Venice, 1564) one of those best-selling books on the secrets of the crafts. His secret for sandarac varnish was adding 1/8th part of "Spanish pitch" to the sandarac. He also includes the earliest mention I have yet found for how to test if the varnish was ready (*).

I don't think he means a balsam, since his general purpose or "common" varnish calls for rosin and specifically mentions pine balsam ("rasa di pino"). Ratio: 4 to 1 + 2 parts of oil.

(*) The same method used over 300 years later: putting a drop on the tip of a knife and pulling a string, and checking to see if it was cloudy or clear:

"il modo di conoscere la cottura di tal vernice è questo, cioè, metterne un cosopra po un coltello, & distenderla col ditto, & se sara untuosa è cotta: ma se sarà lucida & chiara e senza untuosità, sara cotta."

 

Dave

 

Edited August 27 by Alchemia succini
Clarified Dr. Laurie's reference

[Chris Anderson, PhD]

If you want a very long answer... Ms. Lammlien recent received her PhD doing a review of this very topic - providing a very good bibliography.  This is pretty 'material science' engineering-heavy for a read.  

https://www.dora.lib4ri.ch/empa/islandora/object/empa%3A18766

The answer is 'it depends'.  Engineering, as my advisor said is "the judicious manipulation of mid-range values".  

In short - grounds increase rigidity and volume, varnishes provide 'damping'.  The balance between the two, materials and thicknesses result in the overall tone and timbre of the instrument.  Not sure if you meant 'Varnish' or 'Finishing system' - sometimes the term 'varnish' is utilized as referring to the 'whole system'.  

thanks, 

Chris Anderson

[ernym]

2 hours ago, Alchemia succini said:

 I suppose I'm suggesting that rather than use a soft resin bringing its own defects, the inherent shortcomings of a hard varnish can be mitigated by tempering its hardness.

I agree with Claudio though about sandarac varnish. If I were to do it over again today, I would choose sandarac over amber because it has a documented history in the old Italian literature, whereas amber is only to be found here and there and at a later date.

Speaking of this, I'm trying to pull my notes together to start a thread on the varnishes of Dr. Fioravanti, especially his sandarac varnish. An Italian doctor and surgeon (first successful splenectomy; one of the fathers of plastic surgery) he wrote (Venice, 1564) one of those best-selling books on the secrets of the crafts. His secret for sandarac varnish was adding 1/8th part of "Spanish pitch" to the sandarac. He also includes the earliest mention I have yet found for how to test if the varnish was ready (*).

 

Tempering amber's hardness is working well for me.

Making a sandarac oil varnish is not easy and I know of nobody selling it commercially. Last person making and selling it was Koen Padding. His sandarac Vernice Liquida was an excellent varnish. I've heard of others who can make a successful sandarac varnish. I've tried and failed, but I didn't add any pine resin. It would be great to have a recipe that works. For now I'm happy with tempered amber varnish.

[LCF]

3 hours ago, Alchemia succini said:

... Speaking of this, I'm trying to pull my notes together to start a thread on the varnishes of Dr. Fioravanti, especially his sandarac varnish. An Italian doctor and surgeon (first successful splenectomy; one of the fathers of plastic surgery) he wrote (Venice, 1564) one of those best-selling books on the secrets of the crafts. His secret for sandarac varnish was adding 1/8th part of "Spanish pitch" to the sandarac.

 

Dave

 

Thanks for your interesting post. I look forward to the thread you're proposing. 

 

I first used sandarach mixed with plain resin in varnishes made 40 years ago. They were otherwise cooked with linseed oil in the usual fashion. It was something I stumbled over which gave good results.

Molten pine resin (rosin) is a powerful solvent.

 

[Andreas Preuss]

On 8/25/2024 at 6:18 PM, Don Noon said:

As best I can determine, it is the very high frequencies that are damped down by the varnish.

So in theory the right varnish could ‘cut off’ frequencies above 6000 Hz?

Maybe the thickness of varnish could be more relevsnt than the composition. (?)

[Don Noon]

2 hours ago, Andreas Preuss said:

So in theory the right varnish could ‘cut off’ frequencies above 6000 Hz?

Maybe the thickness of varnish could be more relevsnt than the composition. (?)

I would expect it to be more of a "roll off" ...  I have neither tests or theory to say.  Or it could be uniform damping, equal amplitude reduction per cycle for all frequencies, which would take energy out of the highs more quickly.

I agree with the second statment, and try to keep varnish thin.