Magister varnish oil resin ratio

[FredN]

Hi Davide, (post 12), don't understand the purpose of cooking off  the turp.  I think doing that results in leaving high-boiling  substances containing after- tack, and if your vessel is high sided any water in the turp will still be there. Obviously, you wouldn't be doing that if you weren't getting the results you want. fred

[Davide Sora]

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

 

I tried adding a few drops of linseed oil to the amount of varnish needed for each layer to improve the fluidity during application, gradually increasing the amount in each layer to keep the "fat over lean" ratio, and it seems to work fine.

Weighing the quantity added, in the last two layers the ratio has become 3:2 (oil:rosin) starting from a varnish made with ratio 1:1 (2g varnish + 0,5g oil added that is ten drops, previous layers had six and eight drops).

Based on these results I thought to make the next varnish directly with the ratio 3: 2 to avoid adding oil in the application phase and improve the incorporation of oil and rosin, but I'm not sure what is the difference that I could expect in the final properties of the layer.

Some clue?

 

 

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.

 

Referring back to what I wrote above, could you expand on what are the differences that you noticed?

 

 

Davide

[Davide Sora]

Hi Davide, (post 12), don't understand the purpose of cooking off  the turp.  I think doing that results in leaving high-boiling  substances containing after- tack, and if your vessel is high sided any water in the turp will still be there. Obviously, you wouldn't be doing that if you weren't getting the results you want. fred

Hi Fred,

thank you for your comment.

I have added 20% of turpentine and varnish seemed too flowing, hence the decision to make it evaporate after decanting and removal of residues of umber (my varnish is directly "inspired" by your ).

I did not know that this might result in problems of after-tack, but I thought the opposite, since I believe that residues of turpentine, which could remain in the varnish layer, could be responsible of this kind of problems (this is another reason why I decided to remove it).

 

Would you be so kind as to explain me why evaporate the turpentine may cause problems of after-tack?

Sorry for my lack of knowledge in chemistry.....

 

Davide

 

PS Following your precious advice, I used a low container, so I hope that traces of water are not left in.

[Peter K-G]

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.

 

 

 

Referring back to what I wrote above, could you expand on what are the differences that you noticed?

 

 

Davide

 

Hard to explain as the difference is very small. It's when polishing the layer with added linseed oil, it does not react how I want it to. I like to be able to smooth out the varnish warming it up by friction, it gets a really nice finish. I use a linen cloth and small amount of oil (paraffin). If I want to apply another layer of varnish I use linseed oil. Dust and small unevenness gets smoothed out.

 

I apply varnish by hand/fingers and the after polishing without abrasives is now my favorite method, but it requires the right varnish mix, softness (Colophony, linseed oil, mastic). Batches made previously needs a little alcohol to get the same kind of result.

[Peter K-G]

Another issue from many other varnish threads. I have asked this before - Why do you say resin, do you actually use resin?

 

https://en.wikipedia.org/wiki/Rosin

 

I use Colophony (Pine rosin, Greek pitch)

[Davide Sora]

Hard to explain as the difference is very small. It's when polishing the layer with added linseed oil, it does not react how I want it to. I like to be able to smooth out the varnish warming it up by friction, it gets a really nice finish. I use a linen cloth and small amount of oil (paraffin). If I want to apply another layer of varnish I use linseed oil. Dust and small unevenness gets smoothed out.

 

I apply varnish by hand/fingers and the after polishing without abrasives is now my favorite method, but it requires the right varnish mix, softness (Colophony, linseed oil, mastic). Batches made previously needs a little alcohol to get the same kind of result.

Thanks for explaining.

I noticed the same thing, the varnish with oil added is less reactive to hand warmth and alcohol during the final polishing and I had more difficulty to remove dust specs and smoothing the surface.

I do not know if this aspect may change making the varnish with oil added during cooking rather than later during application, but probably the only way to figure it out is to give it a try next time.

Have you ever tried?

I would expect even greater flexibility, at present it seems a bit too fragile (brittle) expecially on spruce that I seal with casein.

 

 

Another issue from many other varnish threads. I have asked this before - Why do you say resin, do you actually use resin?

 

https://en.wikipedia.org/wiki/Rosin

 

I use Colophony (Pine rosin, Greek pitch)

 

When I use resin I refer to all the resins in general, and rosin only for the Colophony from Pine, Spruce, Fir or Larch.

For my varnish I have used Colophony (supposedly Pine) cooked down with lime, zinc and umber for color and to lower the acidity.

[Melvin Goldsmith]

I think that I bought every product that Koen made to test and try.I doubt that anything he sold went beyond 1.2 oil to resin. Certainly some of his later creations were much leaner and I have observed them being used beautifully...even in replacement parts for old Cremonese. It looked the same as original  under UV.

[Davide Sora]

I think that I bought every product that Koen made to test and try.I doubt that anything he sold went beyond 1.2 oil to resin. Certainly some of his later creations were much leaner and I have observed them being used beautifully...even in replacement parts for old Cremonese. It looked the same as original  under UV.

Hi Melvin,

I suppose you mean 1:2 resin to oil, that is 1 part resin and 2 parts oil. Am I right?

Regarding UV fluorescence, in the H.Michetschlager book she refer to "a bright orange fluorescence reminiscent of shellac", that for me is very different from the fluorescence of the ancient varnishes.

She also says that is comparable to varnish containing linseed oil, sandarac and rosin , even if the rosin is very different from shellac regarding the UV fluorescence.

This is somewhat disorienting....

[Melvin Goldsmith]

Hi Davide. I meant 1.2 parts oil to 1 part resin. The book for me is interesting for the evidence it presents rather than any conclusions  Exactly in the same way I look all varnish research

[Davide Sora]

Hi Davide. I meant 1.2 parts oil to 1 part resin. The book for me is interesting for the evidence it presents rather than any conclusions  Exactly in the same way I look all varnish research

 

Ah, thank you for clearing up,I had wrongly interpreted 1.2 as 1:2

It is important to hear from those who have used these varnishes, the 20% of resin content shown in the book seemed a little strange......

Also I'm very careful to draw conclusions from these publications, but it gives me a little annoyed when they create confusion for incomplete or incorrect data reported.

However, not alter the value of the book as a testimony to the work of Koen.

[~ Ben Conover]

The old masters used pine resin, not colophony.
Colophony is a purified form of resin, with the rosin oil taken out. 
 
Various young German / French people at Newark went around collecting pine resin from trees,
which seemed like a lot of hassle considering you can buy colophony
(or extra dark Baltic colophony) without all that hassle.  

Varnish is easy to make, and not difficult to use.
 

[Peter K-G]

Yes Ben,

 

Varnish is easy to make and use, so are violins. Great varnish and how to use, great violins and how to use, not so sure how easy?

For varnish It's learning how to use the ingredients you have. It took 5-6 batches before I settled with the proportions and cooking time I like, but all batches are usable varnish.

 

I'm a little bit stubborn about the resin/rosin term, because it's confusing for a non native English speaking.

I see resin as a liquid form and rosin as solid. Collecting gum from pine trees liquid or hardened is that resin?

[~ Ben Conover]

Bottom line it if varnish is not easy to make and apply something's wrong. 
 

[Peter K-G]

Read it again, pine 'resin' from trees = resin from trees. It's not rosin.

Commercially available 'rosin' = purified resin. 

'Resins' as a chapter heading in a book about varnish, = collective noun. 

Bottom line it if varnish is not easy to make and apply something's wrong. 

There are more complex things to worry about than the chemical analysis and

testing of what is just.....varnish. 

I had thought about logging out for a few days, think I will. 

:-)

 

Absolutely agree

 

I have no interest in complex varnish chemistry either, just want it to work nicely -trial and error.

 

Resins from trees - collective noun, got it

 

Please log on from time to time  

[Urban Luthier]

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.  

 

It is interesting you mention the word 'mix' Joe. My one and only attempt at making varnish was cooked at a very low temperature (60% colophony and 40% oil). I didn't get a string, so i suspect the components didn't chemically form. However it made a very nice varnish.

[Peter Lynch]

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......

I received an email about this from Helen.  She said that it was not entirely clear in the German language report, but she believes it means the total resin content was 20% and the Sandarac was a part of that.  She is going to contact the lab that did the analysis to have it clarified but not sure how long that will take.. 

[FredN]

Hi Davide (post 28), who knows, maybe you discovered the secret for perfect varnish by first cooking off the turpentine. Hope it still worked out.  Turpentine is composed of many compounds and it is possible that some react with the umber present, and possibly with the oil or rosin. The main job obviously of turp is to thin for brushing. Depending how hot the mixture is after it is made ( I start adding turp when cooled to around 475F), I add turp  until a drop on glass will run out and almost form a ring with a hole in the middle, then pull back into a circle with a flat surface. Always better to stop on the side where you might need more turp.

 

The rosin, linseed oil, umber form a chemical interchange to some degree. Text says there is an acid   interchange between rosin and oil, so there is a chemical binding between them. Be glad to answer any questions.  fred 

[~ Ben Conover]

Resin Rosin % to oil as measured before or after cooking will be different.......
So how can you test the stuff Padding made before cooking....you can't. 
 
 

[Melvin Goldsmith]

I really can't believe it when people continue to insist that good varnish is made by prolonged cooking..... talk about stringing etc  This might be the provenance of old amateur text re varnish but if we look at serious painters manuals all varnishes and glazes are cold compounded.I Nice varnish is very easy and simple... might heat treat my oils or resins but normally I combine them with a minimum of heat. 

[Evan Smith]

I just get sap chunks off of a tree,,spread out tarps and scrape the trees with long poles and break off the chunks.

I know of one grove I can get 30 lbs every time I visit.

Cook it till it is drained from the junk,,needles and bark,,

then cook it till it is hard and brittle upon cooling,,,

wash the oil for a summer or so, sitting in the corner of the yard somewhere,

Heat up the oil a bit,, 200-300 or so to be sure there is no moisture,

add the resin.

After it drys,,,If it scratches white,, add more oil,, if it's rubbery add more resin, simple.

 

If you cook it till it pulls a string then it just has to be thinned back out to be use able.

I find it will still dry if it doesn't pull a string, some times it drys in a few hours.

 

You can add driers, umber, manganese, it works great.

 

I have gotten some lime and other things to process the resin with which I have not yet tried.

Who knows maybe it can get better,,

[Melvin Goldsmith]

I just get sap chunks off of a tree,,spread out tarps and scrape the trees with long poles and break off the chunks.

I know of one grove I can get 30 lbs every time I visit.

Cook it till it is drained from the junk,,needles and bark,,

then cook it till it is hard and brittle upon cooling,,,

wash the oil for a summer or so, sitting in the corner of the yard somewhere,

Heat up the oil a bit,, 200-300 or so to be sure there is no moisture,

add the resin.

After it drys,,,If it scratches white,, add more oil,, if it's rubbery add more resin, simple.

 

If you cook it till it pulls a string then it just has to be thinned back out to be use able.

I find it will still dry if it doesn't pull a string, some times it drys in a few hours.

 

You can add driers, umber, manganese, it works great.

 

I have gotten some lime and other things to process the resin with which I have not yet tried.

Who knows maybe it can get better,,

sweeet!

[Salve Håkedal]

Strange how people in this thread seems to find that oil varnish is easy, while some time ago it was my impression that serious makers found it very difficult!

How does your varnish do after being on the instrument after 20 years? Is it still on the instrument? How often have you had to revarnish? Do you tell your customers not to touch it?

(Speaking for myself, I gave up oil varnish.)

[Peter K-G]

I really can't believe it when people continue to insist that good varnish is made by prolonged cooking..... talk about stringing etc  This might be the provenance of old amateur text re varnish but if we look at serious painters manuals all varnishes and glazes are cold compounded.I Nice varnish is very easy and simple... might heat treat my oils or resins but normally I combine them with a minimum of heat. 

 

I think all this arguing over and over again about cooking time etc. must have to do with "wrong" ingredients used. (the other option would be madness). It's almost impossible to fail.

 

Go out and cook varnish people! It's easier than cooking toffee.

[~ Ben Conover]

'Easy' is misleading....you need to be aware of the toxic fumes coming off 
the pan, and how to use a varnish brush effectively. 
It's not 'hard' though. 
 

[Davide Sora]

I received an email about this from Helen.  She said that it was not entirely clear in the German language report, but she believes it means the total resin content was 20% and the Sandarac was a part of that.  She is going to contact the lab that did the analysis to have it clarified but not sure how long that will take.. 

That's how I had interpreted reading the book, that is the total resin content, but it seemed so strange and unlikely that I decided to start this topic.

Please Peter, if there will be a reply from Helen please inform us, it will be greatly appreciated.