Michael Szyper

Kremer's new violin ground

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Hi there, 

 

since this is my first topic I would like to introduce myself. I am a 31-years old medicine doctor and part-time luthier based in Munich, Germany. 

Last week i got the new Kremer Pigmente catalog, where i saw the new "violin ground" which is reported to be based on "old italian alchemistic receipes".

Sounds very mystic to me ;)

According to their website it should reduce damping and harden the wood surface. 

 

Did someone of you try it already?

It would be interesting if there is data about the change of wood damping, but also the density and stiffness changes.

I am planning to buy a bottle at the Cremona Mondomusica this year and then run the usual tests (density, damping, RR/speed of sound) with it before i try it on a violin.

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You need to be more specific.  Is this 79725 Rubio Mineral Ground?  The Rubio ground has been around for years--you can probably still find Rubio's videos on the subject.  It is a method of putting a mineral ground on the wood surface.  Hargrave uses gypsum for this.  Other people make up an emulsion of mineral particles, varnish and glue and so on and so on.  There are lots of methods for doing this.  Many do not believe that there is a mineral ground. 

 

Welcome to confusion.

 

Mike D

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Hello Michael,

you are not far from me. I am just 70km south Munich.
I have seen this Product last year in Cremona at Mondomusica. I was not overrolled by entusiasm. There is nothing new or away from anything what we all allready know and tried out.

 

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Stradivari was NOT a chemical engineer. He did not make these type exotic concoctions. What ever he used probably came from the kitchen and was simple. He was a instrument maker in the seventeenth century.  I have some of the Rubio ground system (sucker born every minuet), It's a stretch, to put it kindly. 

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10 hours ago, JohnCockburn said:

I think Michael is referring to this:

http://www.kremer-pigmente.com/en/new-products/mediums-binders-und-glues/7653/ground-coat-gd

The active ingredient seems to be calcium hydroxide.

Exactly, John. If it would be calcium hydroxide, there would be almost no difference to the plaster of paris ground Roger is using. I tried this ground on my latest violin, which is not strung up yet. According to my measurements the plaster of paris is not reducing the damping of the wood, but the additional damping of the varnish is reduced a little bit. And this is not an unusual effect of nearly all grounds.

 

Michael K., what a small world! If you live in Murnau, that's my definition of paradise... Maybe we could meet some day.

 

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The idea of mineral ground came from Barlow / Woodhouse.  The SEM photos show a thick layer on top of the wood which is misidentified as ground and a thin layer on top of that identified as varnish.  Ground is in the wood not on it.   What those show is more likely either later touch up or varnish with a thin layer of polish on top.   imho 

The idea of silicates came from Sacconi and also propolis.  I think those are wrong too.   

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Michael Szyper---calcium hydroxide and gypsum (Magnesium sulfate) are not the same thing.  Calcium hydroxide has a high pH while gypsum would be neutral pH.

 

MikeC---your definition of ground is very limited.  Most of us would consider the mineral layer to be part of the ground.

 

Mike D

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21 minutes ago, Mike_Danielson said:

Michael Szyper---calcium hydroxide and gypsum (Magnesium sulfate) are not the same thing.  Calcium hydroxide has a high pH while gypsum would be neutral pH.

 

MikeC---your definition of ground is very limited.  Most of us would consider the mineral layer to be part of the ground.

 

Mike D

You are partially right, but gypsum is a calcium sulfate hydroxide. The high ph of caoh2 should not do anything special regarding the wood fiber hardening, what dou you think? In fact all the mystic minerals primary do the same - sealing the pores to avoid varnish penetration. 

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There is no mineral layer at least not in the analysis by B&G or Echard but I'm sure there is mineral ground in some more modern instruments.  

What one means by ground can be variable and depends on what characteristics are wanted in a ground.    Yes my definition is limited and means something very specific.  If other's definition is more generalized then there's nothing wrong with that. 

 

 

 

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1 hour ago, Michael Szyper said:

You are partially right, but gypsum is a calcium sulfate hydroxide. The high ph of caoh2 should not do anything special regarding the wood fiber hardening, what dou you think? In fact all the mystic minerals primary do the same - sealing the pores to avoid varnish penetration. 

Michael, gypsum is calcium sulfate dihydrate  (CaSO4·2H2O), thats a bit different than hydroxide

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I'm with Berl, simplicity-  the mineral ground was patchy, so it could merely be the result of sanding.  If they made bows they had scraps  of pernambuco to extract the dye Brazilin. Surplus or old glue  and lime coating to produce the smooth surface needed for varnish.  Shop made rosin varnish with the possibility of commercially produced copal varnish added for durability. Anybody who had a horse carriage most likely had it.  Compiled after two beers.   fred

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It is interesting that Kremer's new product is listed under mediums, binders and glues.  The description mentions a hardening component and, from appearances, it looks to be more than just calcium hydroxide..  Could something like casein be involved?

Further to Mike C's comment - Barlow and Woodhouse's SEM photos of their Strad samples show particulate layers on/above the wood surface that are in the region of 40 - 60 microns thick.  This is far thicker than what other researchers (e.g., Echard and Brandmair) have noted for identified initial coatings on Strads.

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Peering down the Time Tunnel............

"Monsieur Vuillaume, here are the last of the Tarisio violins."

"Sacre bleu!  They look horrid, just like the others.  That old fool must have kept them in a pigeon coop!  Revarnish the lot!".

:lol::ph34r:

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Let me start by saying Stradivarius is the greatest maker of all time. He has not been a easy act to follow. Over the years sense his death there have been countless stories of his secret varnish, this story was promoted for nearly three hundred years. People finally woke up to the fact that nearly all of his violins varnish is wore off, so it can't be the varnish. Next comes something invisible, ground. This won't be easy to dispel, after all you can't see it. I believe they're are many grounds that work very well, hell Strad may have used what ever he fancied at the moment. After making over sixty violins I just can't make myself believe he brewed some magic concoction that no one else has ever known about. There are new violins being made today that are giving his a real run for their money.

 

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8 hours ago, Berl Mendenhall said:

 There are new violins being made today that are giving his a real run for their money.

A run for the money sound wise or appearance wise?    The old ground has a certain appearance, it may or may not have some sonic property,  I don't know .  

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9 hours ago, John Harte said:

It is interesting that Kremer's new product is listed under mediums, binders and glues.  The description mentions a hardening component and, from appearances, it looks to be more than just calcium hydroxide..  Could something like casein be involved?

Further to Mike C's comment - Barlow and Woodhouse's SEM photos of their Strad samples show particulate layers on/above the wood surface that are in the region of 40 - 60 microns thick.  This is far thicker than what other researchers (e.g., Echard and Brandmair) have noted for identified initial coatings on Strads.

Actually, the Calcium Hydroxide will "harden", not as itself, but through the conversion of Calcium Hydroxide to Calcium Carbonate. Atmospheric CO2 will react with Ca(OH)2, to form CaCO3. This is the same reaction that hardens lime-sand mortar. In the case of thick mortar joints, this can take decades, but as a thin layer in a violin, it would happen pretty quickly.

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4 hours ago, FiddleDoug said:

Actually, the Calcium Hydroxide will "harden", not as itself, but through the conversion of Calcium Hydroxide to Calcium Carbonate. Atmospheric CO2 will react with Ca(OH)2, to form CaCO3. This is the same reaction that hardens lime-sand mortar. In the case of thick mortar joints, this can take decades, but as a thin layer in a violin, it would happen pretty quickly.

Yup.  Basically, you're laying down microscopically thin strata of limestone on your violin, sorta like layers of scale in a pipe.  Maybe, if you're lucky, it's supposed to deposit as transparent or translucent calcite or aragonite, and enhance the optical properties, but I wouldn't hold my breath on that.. :)

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On ‎7‎/‎11‎/‎2017 at 11:34 AM, Michael Szyper said:

You are partially right, but gypsum is a calcium sulfate hydroxide. The high ph of caoh2 should not do anything special regarding the wood fiber hardening, what dou you think? In fact all the mystic minerals primary do the same - sealing the pores to avoid varnish penetration. 

Leaving aside whether it will cause hardening, the ph of the lime will cause the wood to turn a yellowish color that will not happen with calcium sulfate.

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14 hours ago, MikeC said:

A run for the money sound wise or appearance wise?    The old ground has a certain appearance, it may or may not have some sonic property,  I don't know .  

I mean in every way. What do you mean a certain appearance, and it may or may not have sonic properties? 

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In every way? Do you mean there are modern instruments that have a convincing facsimile of the classic Cremonese ground?  I've seen one or two that seem close but not quite.  Of course that's a broad statement.  There may be old Cremona fiddles that don't look all that special. I'm sure there's some variability. 

 I can believe some modern instruments give them a run for their money sound wise.    The old ground may or may not have an effect on the violin sound. we'll never know because you can't strip the ground off one and then play it.  

Finishes are my favorite topic :)

 

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Thank you FiddleDoug and Violadamore for your interesting comments.  The appearance and shelf life of at least 12 months fits better with what you mention as opposed to something involving casein glue.

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