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charliemaine
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27 minutes ago, Jim Bress said:

Thanks for the article. Interesting, but not particularly helpful unless you were looking to either increase or decrease the amount of wood darkening that occurs during kiln drying.

Maybe this adds something:  https://www.researchgate.net/publication/319672461_Reconstructing_historical_recipes_of_linseed_oilcolophony_varnishes_Influence_of_preparation_processes_on_application_properties

More detail here:  https://www.researchgate.net/publication/320555276_Proprietes_physico-chimiques_et_vieillissement_des_vernis_huile_de_lincolophane_de_la_technique_du_luthier_a_la_conservation_des_instruments_de_musique_vernis

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John, it looks like you killed the conversation by introducing some useful technical information.  I appreciate your efforts.

For those who do not want to read the technical paper of Tirat, let me mention that she has found about 400 varnish recipes over 3 centuries of varnish data.  These recipes have as a fundamental characteristic a composition of a drying oil (linseed) and colophony.  She includes detailed recipes for 12 in her paper.

So, it is pretty well established what these historic varnishes have to be.  And a reasonable composition (but it does vary all over the place) is equal weights of oil and colophony cooked to a very high temperature.  She could not go above 250 C in her laboratory.  The varnishes are thixotrophic which is very useful if you brush.

 

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1 hour ago, Mike_Danielson said:

John, it looks like you killed the conversation by introducing some useful technical information.  I appreciate your efforts.

For those who do not want to read the technical paper of Tirat, let me mention that she has found about 400 varnish recipes over 3 centuries of varnish data.  These recipes have as a fundamental characteristic a composition of a drying oil (linseed) and colophony.  She includes detailed recipes for 12 in her paper.

So, it is pretty well established what these historic varnishes have to be.  And a reasonable composition (but it does vary all over the place) is equal weights of oil and colophony cooked to a very high temperature.  She could not go above 250 C in her laboratory.  The varnishes are thixotrophic which is very useful if you brush.

 

I’ve started reading this article and it looks promising. Really I’m just starting the methods section and so far it appears to be well set up to test the questions being asked. I review up to half a dozen research articles a week and it is in the method section that many papers live or die (for my purposes). Sorry John for the slow response. 

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On 5/13/2022 at 8:39 PM, charliemaine said:

My question remains...can I somehow change the leanness of this rosinate varnish?

 If there is a way to make it fatter then I would like to continue to experiment with it. 

I'm certain that I'll be able to use this rosinate varnish to add some color and increase the elasticity/durability by mixing a small amount into another blended varnish.  So far I like where this is going. It has a lot of transparency and color change without any additional pigments other than the very slight amount in the red madder rosinate varnish. This sample stills needs a few more coats...

 

IMG_1334.jpg

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Yes indeed, glad it worked out for you. Being able to mix and match is something a lot of us rely on when one thing or another isn't doing it. Versatility is one of the important factors in a varnish, in my opinion.

Don't know that I answered your question about the Tintura Veneziana, but it's not a stain or dye. It's very much like the Roubo treatment, essentially a limited oxidation accelerator 

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22 hours ago, Jim Bress said:

I’ve started reading this article and it looks promising. Really I’m just starting the methods section and so far it appears to be well set up to test the questions being asked. I review up to half a dozen research articles a week and it is in the method section that many papers live or die (for my purposes). Sorry John for the slow response. 

I agree. 

Not so much of an issue here, but many violin varnish studies also appear to suffer from confirmation bias, either in employing starting points based on questionable prior studies, or interpretation of their own data that is, for various reasons, somewhat limited in its scope.

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2 hours ago, JacksonMaberry said:

Don't know that I answered your question about the Tintura Veneziana, but it's not a stain or dye. It's very much like the Roubo treatment, essentially a limited oxidation accelerator 

A limited oxidation accelerator?....sounds like Nitrite is involved?...with a little feces juice?

I have a gallon of rabbit urine that's several years old, hardly smells....Interested? 

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31 minutes ago, charliemaine said:

A limited oxidation accelerator?....sounds like Nitrite is involved?...with a little feces juice?

I have a gallon of rabbit urine that's several years old, hardly smells....Interested? 

No excretions involved. Just good old fashioned renaissance "chymistry", but yes it operates on the same principle as horse $&#+ liquor. @Advocatus Diaboliand others can attest it's a fair bit more involved and complex in result than nitrite in water.

I'll pass on the piss, but I appreciate the offer. 

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9 minutes ago, charliemaine said:

I suppose the same way they get Wolf, Mountain Lion, Coyote and Fox pee...: )

https://www.wildlifecontrolsupplies.com/animal/NWSRABU.html

"one of the finest urine collectors in the country", hmm, now that's an interesting title,  "say, what do you do for work Bob?"  "Well, I don' like to brag or anything, but...." :lol:....Ole' Johnny over there was never too good at it, poor guy, he should have gone into rabbits instead of the Mountain Lions

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I used to use coyote urine as a scent lure for wildlife population surveys. Still can't forget that smell. Vilest stuff on the planet. I kept waiting for Mike Rowe to stop by and give me a hand. He never did. <_< Now back to your regularly scheduled violin making discussion.   :lol:

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What little I've read about making rosinates it sounds much like making a lake. And then cooking the dried rosinate into the varnish. 

So would Neil Ertzs' madder lake be considered a rosinate varnish if it was cooked into the varnish instead of mulled in?

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14 hours ago, JacksonMaberry said:

Don't know that I answered your question about the Tintura Veneziana, but it's not a stain or dye. It's very much like the Roubo treatment, essentially a limited oxidation accelerator 

 

11 hours ago, charliemaine said:

A limited oxidation accelerator?....sounds like Nitrite is involved?...with a little feces juice?

 

11 hours ago, JacksonMaberry said:

No excretions involved. Just good old fashioned renaissance "chymistry", but yes it operates on the same principle as horse $&#+ liquor. @Advocatus Diaboliand others can attest it's a fair bit more involved and complex in result than nitrite in water.

I remember Roger H. talking about this and mentioned he and Koen Padding working together to produce this primer. I regret never having used the Magister primers. A BVMA talk given that goes further into this concoction.

Saltpetre-BVMA_10.10.pdf

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1 hour ago, charliemaine said:

What little I've read about making rosinates it sounds much like making a lake. And then cooking the dried rosinate into the varnish. 

So would Neil Ertzs' madder lake be considered a rosinate varnish if it was cooked into the varnish instead of mulled in?

Does Neil's lake recipe include rosin? If so that would make it rather unusual.

Cooking a lake into oil does not make a rosinate varnish. It would make something closer to tube paint. Cooking rosinate into oil does, though. 

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6 minutes ago, JacksonMaberry said:

Does Neil's lake recipe include rosin? If so that would make it rather unusual.

Cooking a lake into oil does not make a rosinate varnish. It would make something closer to tube paint. Cooking rosinate into oil does, though. 

Neils madder pigment doesn't contain rosin, just a lake. So the rosinate contains rosin, is dried out and then cooked into the oil? Is the process of making rosinate similiar to Keith Hills varnish recipe? I vaguely remember it uses wood ashes, rosin and water.

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3 minutes ago, charliemaine said:

Neils madder pigment doesn't contain rosin

Then it isn't rosinate. 

You're right that rosinates are in some way like lakes! But they have a major difference that is pretty important. 

Lakes: dye precipitated onto a metal oxide 

Rosinates: dye precipitated onto a rosin-metal complex.

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