scordatura
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Posts posted by scordatura
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1 hour ago, Michael_Molnar said:
I encourage you to read the literature. Start with V. Bucur, “Handbook of Materials for String Musical Instruments” (2016). Therein you will see how many researchers have detected proteins in Strads and other Cremonese instruments. Read the recent work by the Italian researchers at the Arvedi Lab for more work on proteins (2017 and more recent).
Thanks for the heads up on these publications Mike. I will check them out.
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1 hour ago, HoGo said:
Thanks Scordatura, I 've missed the Kreisler among Addies' drawings I was looking for del Gesu in the folder name.... I will not print it butwork with that directly in computer so no printing errors will be included. I found a pic of the Kreisler CT online so will check with that as well.
I also have the Kreisler Strad poster so will start there. Are the numbers and size of drawings acurate on the poster? I can try to create 3D model of that later. And Maybe the Vieuxtemps after that.
Yes the Strad poster is accurate. The only possible variations are in the arching vs. Biddulph and Int. Violin (Herdim). They are not that significant though. Could you share the Kreisler CT image? I found one but it is pretty low resolution. Also are you 3D modeling (Fusion 360)? I am also doing that but have not had time to further my Kreisler model. I have a way to go. I am also going to do the Vieuxtemps next. The Strad poster is on the way.
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14 hours ago, JPOWTC said:
As of yesterday, November 11, Woodcraft in Columbus Ohio has 1 bottle. And they cannot get more!
Thanks. I just ordered it. Rumor has it you are from WV. I used to live there!
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FWIW I did a pretty careful analysis of the Kreisler from the International Violin patterns, Biddulph DG book, Strad Poster, and Addie's outline. What I found was the Int. Violin patterns were pretty good if you want a slightly longer body and cleaned up outline. Addie's was the shortest. Addie posted that his outline might not be printed to scale. Everything in Addie's is OK except the top and bottom. Having seen the Kreisler in person the overhang is not that dramatic in those areas.
The archings kind of agree. The neck Int. Violin (Herdim) was off.
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I was wondering if anyone wanted to part with their F-hole Drill Set like link below? If so PM me.
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10 hours ago, Don Noon said:
I'm sure it does... by making the whole instrument look like a ghost.
As I am unburdened by the need to maintain historical accuracy or appearance, that lets me decide what I want my instruments to look like, and test whatever materials and processes get the desired result.
As the "glue ghost" issue implies, I have found that water-born protein, be it glue or casein or whatever, tends to reduce contrast and visibility into the wood. Maybe that's OK for spruce, but I think it kills off the fire of the maple. And maybe it's even historically accurate... I don't know.
But in my limited observations of a few old Italian instruments, many of them DO look to me rather flat and dull compared to more modern instruments. Below are some comparisons of a modern (mine), with a Guarneri and a Strad taken in the same place, same lighting, same camera. I was especially struck by the complete lack of any sparkle in the spruce... no rays, no nothing, like it was a painting. I have no idea why that would be, but since the same effect was present in the areas of original varnish AND the areas where it was completely worn off, I'm kinda thinking that the cell walls have become extremely opaque. (BTW, my instrument has torrefied wood, and the spruce is a very dark example from my earlier batches).
In any case, the point is to test out all these ideas and make a serious evaluation of what you get, and decide if that's what you want.
Don do you just go with a lean colorless linseed/resin for your first contact? You make your own varnish from what I remember.
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3 hours ago, jezzupe said:
Hmm, I feel kinda dirty looking at those pictures
I know. I thought "I spy with my little eyes". He did open "the book" on camera. Sam Z. Is a good man. Glad to see that once in a while good guys finish first.
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2 hours ago, jezzupe said:
Well for those who may be using egg, I, being a Chickeneer
or Poultryman {one who keeps chickens} am starting to come to the conclusion that not all eggs are the same and that diet modifications in your fowl will modify the end product and characteristics of the egg,it's shell, components and the byproducts of those components.
For example there are those who will feed black oil sunflower seeds regularly,vs just for treats, there is a distinct difference in the eggs quality and characteristics
Just to throw one more potential tangent out there, maybe there were special Stradivarius chickens fed special diets to produce a certain type of glair or base for tempera
edit; not to mention the difference in the eggs based on breed
Ah the nuances of the "you are what you eat" premise. Perhaps I need to rethink my own consumption. That is what my wife tells me...
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@Michael_Molnar I know you are in the process of finalizing your system and formulas but can you expand on your tempera layer 2? As I understand tempera, it is a water soluable medium with collagen, egg, or casein or similar as the medium. From what you have said so far you are not in the casein camp. Are you including linseed oil and resin (1 to 4 lean) in this tempera? If so would it be more of an emulsion? You are also saying that you have a pigment in your layer 2. Is it is a brown, or golden color or am I completely off here?
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This expose on Sam Z recently was shown again on my local PBS station. It is from 2017. I decided to take some screen shots of his notes on two violins. I found this pretty interesting. One thing that caught my eye was calcium oxide then "sauce". Also tap tone pitches in areas of the plates. Corpus and plate weights, etc. He also is using finger planes on an assembled corpus on the outside. Hmm...
https://www.nyc-arts.org/showclips/143081/nyc-arts-profile-samuel-zygmuntowicz
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You may or not be aware of the T2 auctions at Tariso. Gordge cases come up for auction. They are not usually cheap though. https://www.tatimms.com/ is a disciple of Gordge. Very nice work. Hope this helps.
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5 hours ago, David Burgess said:
In other words, I don't think that a color alone under UV light tells you much. I would like to see it fleshed out with chemical analysis.
I disagree. It tells you what it reveals. If it looks good and similar to varnish systems that you are striving to copy under different light sources (sunlight, incandescent, led, and uv) you have more sources of validation. If you are not interested in multiple pieces of evidence or do not care to pursue classical Cremonese varnishes then that is a different story. Chemical analysis is another piece of evidence but outside the realm of possibility for almost anyone but a few researchers, especially the destructive tests.. Besides, when the chemical analysis is revealed, many in the luthier community dispute it...frustrating but interesting at the same time.
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8 minutes ago, MikeC said:
I thought B&G identified it as having a resin content? no? Also they found protein and stain which Echard didn't find.
Yes as I understand it they did not detect only linseed oil. They mention a 4 to 1 resin to linseed oil combination. It might have just been Greiner. I will have to check my book.
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Did you seal before you put on the juice or straight on the wood? If no sealer do you experience any unevenness on the top or back for that matter?
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Electron microscope images (Source John Harte casein top, hide glue bottom) showed that casein is more porous than hide glue (at least in that casein formulation). IF one was going to use a sealer, is this desirable if you seal first and then stain? By stain I mean using an oxidizer like sodium or potassium nitrite or a pigment tempera as Mike Molnar, etc. I think that Mike does not seal...Does the porosity of the casein allow stain penetration but not have an uneven application due to more or less absorption (end grain) when NOT sealing? It seems to me that the concentration and/or thickness of the sealer is also a significant factor.
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Back to the topic...
This is a quote from the B&G book from page 18. This seems to put aside the accidental and possibly insignificant contamination. This is from Greiner's section so the nay sayers have some ammunition here.
"We consistently found significant quantities of protein in the uppermost structure of the wood. ... Had we found only isolated areas of protein on the instruments, we would have had to consider the possibility of glue residue or an accidental transfer of protein, through foodstuffs, for example. However, due to the consistency with which we were able to establish the presence of these proteins in all samples across the entire production span of Stradivari's instruments and at different places on the instruments, the possibility of a coincidence can be ruled out."
This does contradict the findings from Echard where no protein was found.
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The links are to an instrument Greiner made in 2016. Granted images are not as good as viewing in person but they look pretty nice. I would assume from this date that he used a casein sealer. That is unless he has changed his mind. The high res images can be enlarged it you click on them. Might take two clicks.
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1 hour ago, David Burgess said:
Uhm, OK. I'm not sure how that really tells me (or anyone) much.
Yeah, she is very pretty and engaging, but I try to put such things aside when making professional evaluations.
Are you calling into question the validity of the testing or do you have issues with Greiner's or her findings?
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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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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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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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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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Congrats on the best in show!
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BTW the pics of the cello are taken in the main room at B&F. Did anyone notice the painting/ghost of Heifetz in one if the pics?
or Poultryman {one who keeps chickens} am starting to come to the conclusion that not all eggs are the same and that diet modifications in your fowl will modify the end product and characteristics of the egg,it's shell, components and the byproducts of those components.
What to do with spongy American spruce?
in The Pegbox
Posted
Nick do you remember the tree number of your wood?