scordatura

Casein as a Sealer Questions

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Yes I have  done a Google search...

In the B & G Strad Varnish book, one of the clear conclusions is that they believe that casein was used as a sealer. If you subscribe to that, the next question is how do you make and apply it. I have done quite a bit of looking and found there is some variation in the recipe. 

What type of lime? Slaked or Quicklime. Not sure how much difference there would be because when you add water to quicklime it turns it into slaked lime. Roger Hargrave stated that quicklime is best vs. other methods.

How to reduce the acidity? Rinsing, baking soda, or ammonia? I am thinking I would use ph strips to see where it ends up and experiment. Will different PH change the appearance or properties of the glue/size? 

What concentration/percentage to use as a sealer? For hide glue (gelatin) 2-3% has been suggested. I know that some go by the seat of their pants but it would be nice to know the concentration. I would think you would want it relatively thin. Especially if you want to use a stain (nitrite) after.

How many coats or surface buildup does one want?

How does casein appear vs. the other sealers once the varnishing is complete?

 

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I think they find the presence of protein but I don't think they identified it as casein did they?  Do you have the book?  I could be wrong. . 

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I like using ammonia to dissolve the casein, as it evaporates and leaves no PH problem.  I also add a bit of boron-bearing bug killer, which is slightly alkaline and also helps dissolve the casein.  You need to wet out the casein first, otherwise you get globs that take forever to dissolve.

I usually use it on the inside of the instrument.  On the outside, it can seal too well and give a washed-out look, particularly on maple.  I have been using it more often on the spruce, but not the maple.  Usually ~5% concentration.

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1 hour ago, MikeC said:

I think they find the presence of protein but I don't think they identified it as casein did they?  Do you have the book?  I could be wrong. . 

Most definitely casein. I took out a loan to buy the book LOL.

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1 hour ago, scordatura said:

Yes I have  done a Google search...

In the B & G Strad Varnish book, one of the clear conclusions is that they believe that casein was used

 

I would disagree.

on we go,

Joe

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42 minutes ago, joerobson said:

I would disagree.

Are you disagreeing with me stating that they identified casein as the sealer or do you think they were wrong?

I used to know... in your system you do not use a protein sealer?

BTW Joe I get the below message if I click too quickly on your site...It is set pretty aggressively.

Your access to this site has been limited

Your access to this service has been temporarily limited. Please try again in a few minutes. (HTTP response code 503)

Reason: Exceeded the maximum global requests per minute for crawlers or humans.

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1 hour ago, Ernest Martel said:

Look at Davide Sora's video on casein sealer. I used his recipe and it is easy to make and apply. It also looks very nice.

Thanks. I forgot that he did one on casein. His videos are the best!

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The alkalinity of casein glue/size can react with organic colorants, most of which behave like pH indicators. I learned this from Oded Kishony, who cautioned me against it's use for this reason. 

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25 minutes ago, JacksonMaberry said:

The alkalinity of casein glue/size can react with organic colorants, most of which behave like pH indicators. I learned this from Oded Kishony, who cautioned me against it's use for this reason. 

What if there was a ground over the sealer/casein? In the B&G book this is a 4 to 1 resin to oil layer (ground) in between the sealer and color layer that contains no colorants. Perhaps this is why the Cremonese did it this way (allegedly). Thanks for that bit of info.

when I mix up my sauce, I am going to test the ph.

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54 minutes ago, scordatura said:

What if there was a ground over the sealer/casein? In the B&G book this is a 4 to 1 resin to oil layer (ground) in between the sealer and color layer that contains no colorants. Perhaps this is why the Cremonese did it this way (allegedly). Thanks for that bit of info.

when I mix up my sauce, I am going to test the ph.

Sounds ok to me. Some like to get color down very early, and so I thought it worth mentioning that it could cause a purple center line haha!

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I do not seal the wood before adding color, and like that result.  I believe that the Cremonese used proteins in a tempera treatment for the ground. I like the behavior of casein tempera although other proteins such as egg white and collagen work too. Anyhow, the tempera draws color into wood structures which has wonderful optical effects. Amazingly,, the tempera eliminates spruce blotching, so I do not seal the wood.

However, the downside to this ground system is the difficulty to get good adherence with the varnish. It's a chemical polarity issue so the tempera must not cover the wood, but infuse it. This is what B&G referred to as "impregnation".

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7 minutes ago, Michael_Molnar said:

I do not seal the wood before adding color, and like that result.  I believe that the Cremonese used proteins in a tempera treatment for the ground. I like the behavior of casein tempera although other proteins such as egg white and collagen work too. Anyhow, the tempera draws color into wood structures which has wonderful optical effects. Amazingly,, the tempera eliminates spruce blotching, so I do not seal the wood.

However, the downside to this ground system is the difficulty to get good adherence with the varnish. It's a chemical polarity issue so the tempera must not cover the wood, but infuse it. This is what B&G referred to as "impregnation".

That's very interesting and useful information , Michael. Thanks. So sounds like you have to take a light touch with the application of tempera, which I assume is colored with madder.

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15 minutes ago, Michael_Molnar said:

I do not seal the wood before adding color, and like that result.  I believe that the Cremonese used proteins in a tempera treatment for the ground. I like the behavior of casein tempera although other proteins such as egg white and collagen work too. Anyhow, the tempera draws color into wood structures which has wonderful optical effects. Amazingly,, the tempera eliminates spruce blotching, so I do not seal the wood.

However, the downside to this ground system is the difficulty to get good adherence with the varnish. It's a chemical polarity issue so the tempera must not cover the wood, but infuse it. This is what B&G referred to as "impregnation".

By tempera color do you mean casein with pigments, an oxidizer like potassium nitrite or sodium nitrite (stain) or an emulsion with casein and a lean varnish? 

Isn’t the lack of adhesion issue mainly with the colored varnish over the ground (non colored lean varnish) chipping away? This seems to be very evident in Cremonese varnish systems.

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After rereading your post Mike, you are saying that there is no sealer. The ground infuses or penetrates the wood and builds up to form a surface layer presumably put on thick or in multiple coats. So now we have a two layer system with just ground and colored varnish. There is defiantly a ground surface layer above the wood. Interesting. 

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6 hours ago, scordatura said:

Are you disagreeing with me stating that they identified casein as the sealer or do you think they were wrong?

I used to know... in your system you do not use a protein sealer?

BTW Joe I get the below message if I click too quickly on your site...It is set pretty aggressively.

Your access to this site has been limited

Your access to this service has been temporarily limited. Please try again in a few minutes. (HTTP response code 503)

Reason: Exceeded the maximum global requests per minute for crawlers or humans.

Brandmair was quite specific with me about the findings.  Amino acids were identified on the surface. 

 

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31 minutes ago, joerobson said:

Brandmair was quite specific with me about the findings.  Amino acids were identified on the surface. 

 

Ok so protein. Can you expand on that?

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2 hours ago, joerobson said:

Brandmair was quite specific with me about the findings.  Amino acids were identified on the surface. 

 

So you disagree with Amino acids equals Casein, right?

 

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2 hours ago, JacksonMaberry said:

That's very interesting and useful information , Michael. Thanks. So sounds like you have to take a light touch with the application of tempera, which I assume is colored with madder.

I like water-soluble colorants, non particulate, which fit Brandmair's findings.

2 hours ago, scordatura said:

By tempera color do you mean casein with pigments, an oxidizer like potassium nitrite or sodium nitrite (stain) or an emulsion with casein and a lean varnish? 

Isn’t the lack of adhesion issue mainly with the colored varnish over the ground (non colored lean varnish) chipping away? This seems to be very evident in Cremonese varnish systems.

Artist tempera as it was made in the Renaissance. I suspect that excess tempera leaves a polar medium to which non-polar varnish does not stick. This flakiness lies between Layer 2 (pore filler ground) and Layer 3 (colorless varnishing).

2 hours ago, scordatura said:

After rereading your post Mike, you are saying that there is no sealer. The ground infuses or penetrates the wood and builds up to form a surface layer presumably put on thick or in multiple coats. So now we have a two layer system with just ground and colored varnish. There is defiantly a ground surface layer above the wood. Interesting. 

Excess tempera fills the pores. It is impossible to not leave some tempera on the wood. In fact, I don't think that that's advisable.

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2 minutes ago, Andreas Preuss said:

So you disagree with Amino acids equals Casein, right?

 

Amino acids are constituents of proteins. I am intrigued that the Cremonese did not know about proteins per se, yet three of their temperas used either albumin, collagen, or casein - all proteins. Evidently, intuitive alchemistry led them in the direction that produced results.

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FWIW  (if anything), way back when, Sacconi reported (I segreti) that electron microscopy of a tiny sample he had provided the lab showed that something had soaked into the fibres of the wood, but wasn't in the empty spaces between them. This would have been the foundation, under everything else.

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Scordatura, you may find some answers to your initial queries in this thread: https://maestronet.com/forum/index.php?/topic/328546-darkening-the-violin-wood/  A discussion of casein grounds starts on page 3.

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8 hours ago, Andreas Preuss said:

So you disagree with Amino acids equals Casein, right?

 

Yes. Ms. Brandmair holds to the findings without speculation.   Taking the findings and testing methods to those familiar with the tests was revealing.   The test is extremely sensitive.  The protein on the surface could be egg from breakfast, glue smears, or most likely the evidence that the wood was handled by humans. 

Beyond that,  the other characteristics of the Ground do not agree with a casein sealed surface.

Protein grounds can be quite effective.   It is just not as found on the classic Cremonese instruments that have been studied.

on we go,

Joe

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15 minutes ago, joerobson said:

Yes. Ms. Brandmair holds to the findings without speculation.   Taking the findings and testing methods to those familiar with the tests was revealing.   The test is extremely sensitive.  The protein on the surface could be egg from breakfast, glue smears, or most likely the evidence that the wood was handled by humans. 

Beyond that,  the other characteristics of the Ground do not agree with a casein sealed surface.

on we go,

Joe

So why did she publish something which doesn't reveal any significant information about the true 'problem'? 

Anyway good to know.

 

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Just to clarify, the casein sealer was stated by Greiner in his section of the book. Joe is disagreeing with that and not the testing methodology or the results per say in Brandmair's section. It seems to me that even though the number and physical size of samples is limited, there might be some way to determine the amount of and frequency of protein/amino acids across the samples in the various strata. This might show if the protein found was accidental contamination or not. Any thoughts on this?

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