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Davide Sora

Magister varnish oil resin ratio

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Reading the book "Violin varnish - notes and article from the workshop of Koen Padding" by Helen Michetschläger, I noticed that the results of chemical analysis of Koen's varnish indicate that "the (resin) proportion is estimated to be under 20%" (p.127), which should correspond to a ratio of 4 : 1, that is a long oil varnish.

Given my liking to avoid solvents and thinners in the varnish, I found this very interesting, considering also the high regard that Koen's varnish had gained among violin makers.
I have never used nor handled Magister varnishes, and I'd be curious to hear from those who have used them about these results on their composition and their impressions about using them.
I would expect a varnish sufficiently fluid, which can be applied without the addition of solvents or thinners, but I am quite concerned by such a high content of oil on the final characteristics of the varnish as toughness, gloss and polishability.

 

 

 

 

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Here we go, I can see this baby going on for several days.  Davide, I don't understand the reluctance to add turpentine to the mix while the varnish is still hot.  Adding it to cold varnish I could understand.  I think that adding it to hot varnish actually incorporates it in the mix, I believe that came from Joe actually.  I've never used really thick oil varnish, by thick I mean like peanut butter thick.  my varnish has always been brushable.   

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Here we go, I can see this baby going on for several days.  Davide, I don't understand the reluctance to add turpentine to the mix while the varnish is still hot.  Adding it to cold varnish I could understand.  I think that adding it to hot varnish actually incorporates it in the mix, I believe that came from Joe actually.  I've never used really thick oil varnish, by thick I mean like peanut butter thick.  my varnish has always been brushable.   

 

Please! Read posts of another peoples here on Maestronet with "two eyes"! Davide wrote about something different than You answer.

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Reading the book "Violin varnish - notes and article from the workshop of Koen Padding" by Helen Michetschläger, I noticed that the results of chemical analysis of Koen's varnish indicate that "the (resin) proportion is estimated to be under 20%" (p.127), which should correspond to a ratio of 4 : 1, that is a long oil varnish.

Given my liking to avoid solvents and thinners in the varnish, I found this very interesting, considering also the high regard that Koen's varnish had gained among violin makers.
I have never used nor handled Magister varnishes, and I'd be curious to hear from those who have used them about these results on their composition and their impressions about using them.
I would expect a varnish sufficiently fluid, which can be applied without the addition of solvents or thinners, but I am quite concerned by such a high content of oil on the final characteristics of the varnish as toughness, gloss and polishability.

 

 

David,

Although the exact oil to resin ratios of the Magister Varnishes is not known, it is common knowledge that they contained considerably more oil than resin.

This will effect polishability, abrasion resistance, and other factors in the finished film.

The viscosity of oil varnish can be adjusted in the varnish making independent of the issue of the use of raw solvents.  

on we go,

Joe

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building on Davide's post about the 

 

 

..."the (resin) proportion is estimated to be under 20%" (p.127), which should correspond to a ratio of 4 : 1, that is a long oil varnish...

 

I was wondering about this also, in looking at applications methods where pigment is mulled into linseed oil and added to the varnish, wouldn't this increase the overall oil to resin ration even further? 

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UL,

No.  Oil to resin ratio is determined by the varnish cooking.  Adding other materials post cooking makes a mixture of materials, but does not combine with the varnish in a way that effects the oil:resin ratio.

Joe

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Reading the book "Violin varnish - notes and article from the workshop of Koen Padding" by Helen Michetschläger, I noticed that the results of chemical analysis of Koen's varnish indicate that "the (resin) proportion is estimated to be under 20%" (p.127), which should correspond to a ratio of 4 : 1, that is a long oil varnish.

Given my liking to avoid solvents and thinners in the varnish, I found this very interesting, considering also the high regard that Koen's varnish had gained among violin makers.
I have never used nor handled Magister varnishes, and I'd be curious to hear from those who have used them about these results on their composition and their impressions about using them.
I would expect a varnish sufficiently fluid, which can be applied without the addition of solvents or thinners, but I am quite concerned by such a high content of oil on the final characteristics of the varnish as toughness, gloss and polishability.

 

I have been reading this book as well with interest.  I am not sure if I read the percentage the same as you are in that reference.  It says that each sample contains Sandarac (the proportion is estimated to be under 20%).  I thought that this refers only to the Snadarac and not the total resin % necessarily, but I could be wrong

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I used Magister varnish a bit, but they never suited me because of the large oil/resin ratio, or at least the feeling of it.

I understand that Koen Padding didn't mean to make varnishes that look like 300 years old before the are 300 years old.

The problem I had with fat varnishes was always with the drying. A film dries fast at the surface and prevents the rest of the coat from drying, causing unwanted craquelure, as well as wrinkles and other things. To avoid that the solution was to apply very thin films, and I find that is quicker with a thinned down varnish.

But the high oil content makes the varnish difficult to Polish and less sensitive to alcohol, so it doesn't fit with today's taste (whether copies or new), in my opinion!

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Here we go, I can see this baby going on for several days.  Davide, I don't understand the reluctance to add turpentine to the mix while the varnish is still hot.  Adding it to cold varnish I could understand.  I think that adding it to hot varnish actually incorporates it in the mix, I believe that came from Joe actually.  I've never used really thick oil varnish, by thick I mean like peanut butter thick.  my varnish has always been brushable.   

I hope so, this argument is always interesting :)

I must admit that I also add the turpentine at the end of cooking (hard to ignore the hints of Joe Robson) for improving the amalgam of the components (maybe) and especially to decant residues.

But I leave it to settle for three days and then I boil off at 170 ° almost all the turpentine.

I'm not sure it's the best thing to do, but at the moment I'm trying so, perhaps because of my dislike for the shrinking of the varnish caused by the solvent content, developed over years of  alcohol varnishing.

It is so nice to see how a solvent free varnish has the ability to not shrink into the wood pores, unimaginable with alcoholic varnishes.

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While we are on the Magister topic, I just attempted to incorporate Sandarac into oil (and colophany).  I cooked the sandarac and incorporated hot oil.  It seemed to be going well.  It seemed that the sandarac was mixing with the oil (no solid residue present ) and I continued to cook it.  When I took it off the heat for under 30 seconds, a large amount of what looked like sludge that immediately hardened and formed on the bottom of pot.  I poured off and strained the liquid (which was darker then just oil) and heated it back up.  I then added the cooked colophany.  When I weighed the left over hardened sludge I figured I had about 6% sandarac  left in varnish as total %.  My initial idea was to have around 15 %.  I added extra colophany and some cooked vinetian turpentine to bring total mix to about 50/50 oil to resin.

 

I have never attempted to cook Sandarac into an oil varnish so I am 99% unsure of what is actually in the varnish as far as the "sandarac" goes.  Any one with experience with this to help clue my in to what may have happened or what I have?

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I have been reading this book as well with interest.  I am not sure if I read the percentage the same as you are in that reference.  It says that each sample contains Sandarac (the proportion is estimated to be under 20%).  I thought that this refers only to the Snadarac and not the total resin % necessarily, but I could be wrong

I'm sure you understand better what is written in the book because of my poor command of the language, but I think if they refers only to sandarac, this is the only resin that has been identified and the only one that is present in the Koen's varnishes.

However I do not think it's difficult to identify rosin, which I think that is chemically clearly distinguishable from sandarac, so why not also mention the proportion of rosin?

It would be nice if Helen Michetschläger clarify this by intervening on this forum, to eliminate these doubts which may be sound like a false track.

Chemical analyzes are science, and should be reported in a complete and scientific way, not only as a side element that creates doubts......

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I'm sure you understand better what is written in the book because of my poor command of the language, but I think if they refers only to sandarac, this is the only resin that has been identified and the only one that is present in the Koen's varnishes.

However I do not think it's difficult to identify rosin, which I think that is chemically clearly distinguishable from sandarac, so why not also mention the proportion of rosin?

It would be nice if Helen Michetschläger clarify this by intervening on this forum, to eliminate these doubts which may be sound like a false track.

Chemical analyzes are science, and should be reported in a complete and scientific way, not only as a side element that creates doubts......

Davide, You may be correct, but would be good to hear from Helen if possible.  Your question about what happens to linseed oil added after cooking (and how this effects the dried varnish) is one I have had as well :)

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Koen told me in an email that the Vernice Liquida varnishes were over 60% oil. I only tried the Linea Cremonese varnishes which he said were leaner, below 50% oil, though they seemed much fatter in use to me.

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While we are on the Magister topic, I just attempted to incorporate Sandarac into oil (and colophany). I cooked the sandarac and incorporated hot oil. It seemed to be going well. It seemed that the sandarac was mixing with the oil (no solid residue present ) and I continued to cook it. When I took it off the heat for under 30 seconds, a large amount of what looked like sludge that immediately hardened and formed on the bottom of pot. I poured off and strained the liquid (which was darker then just oil) and heated it back up. I then added the cooked colophany. When I weighed the left over hardened sludge I figured I had about 6% sandarac left in varnish as total %. My initial idea was to have around 15 %. I added extra colophany and some cooked vinetian turpentine to bring total mix to about 50/50 oil to resin.

I have never attempted to cook Sandarac into an oil varnish so I am 99% unsure of what is actually in the varnish as far as the "sandarac" goes. Any one with experience with this to help clue my in to what may have happened or what I have?

Did you fuse the sandarac first? Like amber, it doesn't dissolve well in oil if it hasn't been melted before.

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If the components of old Italian varnish are pine resin and linseed oil, 
then the ratio of oil to resin can be roughly determined by how long it took to dry.
Since Strad wrote a letter saying 'sorry for the slow drying time', we can 
work out roughly what the ratio he used was, considering the different drying times 
with ratios of oil to resin. 

Gary Bease says drying time can be calculated whilst cooking by testing the string length, 
but sometimes the varnish string won't increase  no matter how long you cook it, yet it will dry ok afterwards.

 

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One of my best varnish batches ever cooked was a colopophy-mastic/linseed oil in a proportion of 1 resin to 1.75 oil, no solvent added. I made a HUGE batch and I am running low now after 5 years of using it. The stuff is easy to apply the way Magister varnishes were applied and all that has been said above about fatty varnishes is true in this one, doesn't like polishing at all, I just leave it as it is in the last coat. 

 

I use other varnishes of 1 resin to 0.8 oil as well, and on these I do add turpentine while cooking. They are easier to put on in thin coats like P.Belin says and polish very well. They are good for antiquing, they chip out well. (hahhaa, they fail misserably in fact). 

 

When I have made the same ratio of heavily cooked down colophony and oil without solvent the result is very hard and sticky and doesn't suit my aplication method, so I don't really experiment with them that much. 

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Thanks Joe to try to contribute to this topic, going against your professional convenience as always :) 

I can understand that the oil resin ratio is determined during cooking, but if you add cold oil prior to application to promote flowability, where does it go?

It should have some influence on the physical condition of the final layer of varnish, considered that it does not evaporate like a solvent or a thinner.

I remember Geary Baese recommended adding it to this purpose, and also remember that the violin maker Peter Goodfellow said (somewere on this forum) adding it to maintain a favorable ratio of fat over lean during varnishing.

Am I missing something?

Davide,

The oil and varnish mixture [or oil pigment/varnish mixture, etc.] will have different flowing and drying properties...but they are just a mix.  The varnish is a completely reacted material which is now a substance different from the oil or resin in their raw states. The physical changes to the surface are minimal as the actual amount of linseed oil added is minimal.

The fat over lean rule applies only to the formulas of the varnish in the layers.

on we go,

Joe

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I see Davide's point, because the added linseed oil to the varnish must trap it somehow in the layer (even if the amount can be quite small). From my tests this is evident when cold pressed linseed oil is added to varnish for easier application. Layers with added oil is different from only varnish layers.

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Did you fuse the sandarac first? Like amber, it doesn't dissolve well in oil if it hasn't been melted before.

I melted the Sandarac first, not sure the tempature it was at when I incorporated the hot oil.  My IR thermometer was not working,   Not sure of difference of temp between melting and fusing.  It did not get to boiling state..

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If I remember right you have to melt it, let it cool down and then you can incorporate it, but I'm not 100% sure the cooling is a necessary step.

Otherwise I don't know what went wrong with your batch...

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