Can I use Borax instead of ammonia in casein coating?

[violins88]

Davide Sora specifies ammonia and slaked lime with casein, as a coating, both inside and outside of the violin. I can not find pure ammonia (ammonia without soap) here. Can I substitute borax for ammonia?

As usual, I am confident the expertise here on Maestronet will help me out.

Thanks,

 

John

[Davide Sora]

Yes, virtually any alkaline substance is capable of dissolving casein, forming the corresponding caseinate.

This is an example of Borax-casein:

https://www.kremer-pigmente.com/en/shop/mediums-binders-glues/63220-schmincke-casein-binder.html

[violins88]

Davide,

Thanks. I found this as well.

https://www.sinopiamilkpaint.com/recipe

[Davide Sora]

2 hours ago, violins88 said:

Davide,

Thanks. I found this as well.

https://www.sinopiamilkpaint.com/recipe

it seems like a good recipe given its simplicity, but I have never tried to dissolve casein with borax to know what the effective proportions are. Surely it will need to be diluted a lot to bring it to proportions more suitable for a wood-size, I don't go beyond 4% or 5% of casein in relation to the total amount of water.

[Michael Darnton]

If it matters, only lime casein is waterproof, supposedly.

[Davide Sora]

33 minutes ago, Michael Darnton said:

If it matters, only lime casein is waterproof, supposedly.

Yes, as far as I know it is only the calcium hydroxide that triggers the reaction which leads to the water-resistance.

[violins88]

I hope that a very humid day will not cause the finish to come off. I read that borax has a lower pH than lime and ammonia. I will be testing borax casein with madder tincture, which is yellow.

[Michael Darnton]

The main issue would probably be whether the undercoat could withstand washing out of cracks prior to gluing. On glue-sized German instruments too much hot water can loosen the glue from underneath and float away varnish next to a crack, leaving a retouch nightmare.

[Melvin Goldsmith]

Casein application  can result in cracks 

[Michael Darnton]

Yes. I did that on a couple of violins. For a while everything was fine, then a couple of years later the casein started to shrink, dragging surface cracks open--the kind that go halfway through and you can't glue shut. I also discovered that unlike my usual varnish plan which continues to get better and better with age as it clarifies and deepens in the wood, what I saw on day one with casein was the way it was going to look forever. Not that great, really. I guess if I'd done less I'd just have the lousy look without the cracks. :-)

But hey. People will do what they will do. :-)

[violins88]

Michael,

 

Thanks for sharing your experience.

 

[Davide Sora]

13 hours ago, Melvin Goldsmith said:

Casein application  can result in cracks 

 

12 hours ago, Michael Darnton said:

Yes. I did that on a couple of violins. For a while everything was fine, then a couple of years later the casein started to shrink, dragging surface cracks open--the kind that go halfway through and you can't glue shut. I also discovered that unlike my usual varnish plan which continues to get better and better with age as it clarifies and deepens in the wood, what I saw on day one with casein was the way it was going to look forever. Not that great, really. I guess if I'd done less I'd just have the lousy look without the cracks. :-)

But hey. People will do what they will do. :-)

I have the impression that this problem can arise if casein is used in too high concentrations. I also have the impression that casein does not really cause cracks, but that it can cause pre-existing but not visible surface cracks to open. It is probably also the reason why some prefer to add a few drops of linseed oil in emulsion to make it more elastic, although this decreases the surface stiffening effect which is one of the reasons why I like to use proteins, especially for spruce.

But hey. People will do what they do, consciously assuming all the risks involved.

[Michael Darnton]

I still have the worst violin. There was more than one crack and I really don't think it was the wood, but used too strong, yes, I am sure, came to that conclusion, and used it thinner for the next couple of trials. I decided not to use a substance that depended on concentration {thickness on the wood, basically) to mitigate it's natural tendency to damage the wood, though. Similar to the logic we use in choosing foods.

Would the oil blend with the casein, or just separate as it would in a raw oil and resin mix? I'm doubtful. Perhaps it softened the wood underneath so that it wouldn't rip, balancing the casein hardness.

Which brings up the other reason I stopped: after a few trials i did not really see a tonal advantage.

[Davide Sora]

2 hours ago, Michael Darnton said:

I still have the worst violin. There was more than one crack and I really don't think it was the wood, but used too strong, yes, I am sure, came to that conclusion, and used it thinner for the next couple of trials. I decided not to use a substance that depended on concentration {thickness on the wood, basically) to mitigate it's natural tendency to damage the wood, though. Similar to the logic we use in choosing foods.

This is a good precautionary attitude

Would the oil blend with the casein, or just separate as it would in a raw oil and resin mix? I'm doubtful. Perhaps it softened the wood underneath so that it wouldn't rip, balancing the casein hardness.

I also have this same perplexity, another reason why I have never tried to make an emulsion with oil

Which brings up the other reason I stopped: after a few trials i did not really see a tonal advantage.

On the other hand, I seem to hear some acoustic advantages, which is why I haven't stopped using it. Perhaps it depends on wood thickness, with more robust thicknesses or higher density wood the effect may be lost.

 

[John Harte]

14 hours ago, Michael Darnton said:

Would the oil blend with the casein, or just separate as it would in a raw oil and resin mix? I'm doubtful. Perhaps it softened the wood underneath so that it wouldn't rip, balancing the casein hardness.

Casein glue in oil and oil in casein glue emulsions are reasonably easy to make and these, if well made, will hold together.  It is also possible to make casein glue in oil varnish and oil varnish in casein glue emulsions.

The first of the below features casein glue on spruce while the second features a casein glue and oil varnish emulsion on spruce.  (Unfortunately I haven't noted whether the latter was casein glue in oil varnish or oil varnish in casein glue..)

The third shot is an SEM image of a casein glue in linseed oil emulsion on maple.  (The emulsion also includes pumice particulates.)  The material that has penetrated into the large vessel/pore looks to have held together reasonably well.

@ Davide, your mention of adding a few drops of linseed oil in emulsion to make casein glue more elastic is the opposite phase to what is shown in the SEM image.  I have certainly tried linseed oil in casein glue emulsions and may have an SEM photo but would have to go searching for that.  My recollection is that linseed oil in casein glue emulsions work satisfactorily.

FWIW, I am not a fan of casein glue based sizes...

[scordatura]

I can verify that Davide Sora’s instruments are spectacular in their appearance. The playability is pretty darn good too!

[JacksonMaberry]

I posted a borax casein glue/size recipe recently. Borax has very limited solubility in water, so using the correct amount is helpful - you don't want it in excess. The use of a lab hotplate with magnetic stirrer helps make it happen quickly and completely. If the glue will not go completely smooth, you've used too much casein. Add more saturated borax solution and stir until smooth. Then dilute as per Davide - if using it as a size and not a glue, you don't want it very concentrated. 

Research seems to indicate (Echard) that a oil/resin ground was most common in old Cremona. Casein coatings are unfortunately reactive and can affect subsequent color applications.

[Davide Sora]

3 hours ago, scordatura said:

I can verify that Davide Sora’s instruments are spectacular in their appearance. The playability is pretty darn good too!

Thanks!

[Davide Sora]

2 hours ago, JacksonMaberry said:

Research seems to indicate (Richard, Brandmair) that a oil/resin ground was most common in old Cremona. Casein coatings are unfortunately reactive and can affect subsequent color applications.

I don't know if Brandmair has changed her mind, but in her book "Stradivari varnish" she indicated proteins, not oil/resin.

I had attended one of his workshops at the Cremona school where he also showed how to make casein with lime (without ammonia), and how to use it directly on wood

 

[JacksonMaberry]

Just now, Davide Sora said:

I don't know if Brandmair has changed her mind, but in her book "Stradivari varnish" she indicated proteins, not oil/resin.

 

I think you're right, it's been too long since I borrowed and read it! I mixed her and Echard up, I think. 

[Davide Sora]

1 minute ago, JacksonMaberry said:

I think you're right, it's been too long since I borrowed and read it! I mixed her and Echard up, I think. 

[John Harte]

9 hours ago, Davide Sora said:

I don't know if Brandmair has changed her mind, but in her book "Stradivari varnish" she indicated proteins, not oil/resin.

Maybe adding a little more...   In the book “Stradivari Varnish” Brandmair does mention detecting what she terms a “proteinaceous pre-treatment” in various Strad varnish micro-samples.  However she also states that she was unable to actually see any evidence of such in any of the micro-samples using VIS and UV microscopy.  In other words there did not seem to be any physically observable discrete protein based layer on the wood surface or filling the upper wood cell structure.  Instead she noted that, at a minimum, “fibre cavities near the surface are filled with colourless varnish.”  (At times she noted “deep penetration of the wood with colourless and coloured varnish”.)

Both Echard and his team, and the Arvedi Laboratory group associated with the Museo del Violino in Cremona, have also detected some form(s) of protein presence in Strad varnish systems.  However, like Brandmair, they have not been able to see actual physical evidence of any discrete protein based layer in any of their Strad varnish micro-samples.  In contrast both research groups have been able to readily detect and observe discrete protein based layers in other violin varnish micro-sample material.

Apologies to the original poster. This is getting well away from his query.

[JacksonMaberry]

12 minutes ago, John Harte said:

Maybe adding a little more...   In the book “Stradivari Varnish” Brandmair does mention detecting what she terms a “proteinaceous pre-treatment” in various Strad varnish micro-samples.  However she also states that she was unable to actually see any evidence of such in any of the micro-samples using VIS and UV microscopy.  In other words there did not seem to be any physically observable discrete protein based layer on the wood surface or filling the upper wood cell structure.  Instead she noted that, at a minimum, “fibre cavities near the surface are filled with colourless varnish.”  (At times she noted “deep penetration of the wood with colourless and coloured varnish”.)

Both Echard and his team, and the Arvedi Laboratory group associated with the Museo del Violino in Cremona, have also detected some form(s) of protein presence in Strad varnish micro-sample material.  However, like Brandmair, they have not been able to see actual physical evidence of any discrete protein based layer in any of their Strad varnish micro-samples.  In contrast both research groups have been able to readily detect and observe discrete protein based layers in other violin varnish micro-sample material.

Apologies to the original poster. This is getting well away from his query.

Thanks so much, John. That's what I remembered, so I'm glad I haven't lost my marbles.

[Davide Sora]

11 hours ago, John Harte said:

Maybe adding a little more...   In the book “Stradivari Varnish” Brandmair does mention detecting what she terms a “proteinaceous pre-treatment” in various Strad varnish micro-samples.  However she also states that she was unable to actually see any evidence of such in any of the micro-samples using VIS and UV microscopy.  In other words there did not seem to be any physically observable discrete protein based layer on the wood surface or filling the upper wood cell structure.  Instead she noted that, at a minimum, “fibre cavities near the surface are filled with colourless varnish.”  (At times she noted “deep penetration of the wood with colourless and coloured varnish”.)

Both Echard and his team, and the Arvedi Laboratory group associated with the Museo del Violino in Cremona, have also detected some form(s) of protein presence in Strad varnish systems.  However, like Brandmair, they have not been able to see actual physical evidence of any discrete protein based layer in any of their Strad varnish micro-samples.  In contrast both research groups have been able to readily detect and observe discrete protein based layers in other violin varnish micro-sample material.

Apologies to the original poster. This is getting well away from his query.

Thanks John for your posts and pictures, good as usual. 

I would like to see if under the electron microscope an application of low concentration casein (4%) and covered with all the other layers of primer and paint, would be perceivable as a well-defined layer, or if it were identified as a "presence of proteins" only. What I think is that if Stradivari used proteins, it certainly wasn't to form a layer (see Woodhouse's particulate ground), but only as a very light wash-coat.

But alas I don't have an electron microscope on hand...

[John Harte]

@Davide, nor me...    My looking at various ground and varnish systems under SEM was a long time ago (1990 – 1992).  Today's SEM machines are hugely more powerful and should allow you to see the type of very low concentration application that you are describing.  Even the now antiquated SEM that I had access to was capable of providing some indication of layering within varnish systems (See below photo) and certainly any single thin application of something like a casein size.

Having said this, I don't think that SEM is the ideal tool for the job.  It is not capable of detecting protein presence as such.  If micro-sample material was available, something like VIS and UV microscopy combined with some form of micro or nano-FTIR would be much better suited.

A very light wash coat of a very low concentration protein based glue size may be what Stradivari used but I suspect that the researchers that we have mentioned would likely have been able to observe that in their micro-sample material.  I may be wrong though..  Possible explanations of protein presence in varnish systems is a huge topic on its own, I suggest well outside the scope of this particular thread......