Varnish making - questions for the chemists

[FredN]

Fred , but that is Terebinth (original terpentine), also called Terminthos or Terebenthos. I think cedar oil is a mistake somewhere along the line.

I checked to see if I got it right and the copy was ok and I omitted a word in parenthesis written is some strange language that I couldn't copy. Sorry that is all I can add. fred

[Jacob]

The latest batch of responses has been most illuminating (to me, at least). My thanks to all contributors and private PMs.

[CarloBartolini]

 

 

Fred , but that is Terebinth (original terpentine), also called Terminthos or Terebenthos. I think cedar oil is a mistake somewhere along the line.

I checked to see if I got it right and the copy was ok and I omitted a word in parenthesis written is some strange language that I couldn't copy. Sorry that is all I can add. fred

 

 

Perhaps the mention of Herodotus of cedar oil being used on mummification?

 

Maybe this document gives a clue? (hit the page and search "cedar")

PISTACIA SPECIES IN RELATION TO THEIR USE AS VARNISH AND “INCENSE” (sntr) IN PHARAONIC EGYPT

 

Add to that-  the name Cedar is a confusing one in history, here are some excerpts:

 

...The term ' cedar' seems to have been as indefinite in ancient as in modern times. Now we find it applied to the wood of Yunipersis virginiana, which is red or pencil cedar ; and to that of J. Bermudiana or Bermuda cedar. J. oxycedrus yields the cedar of the north of Spain and south of France, but the term is also applied to many other woods, as to white cedar, that of Melia Azedarach ; and Indian cedar, that of Cedrela Toona

 

Another

 

...The earliest notice of the cedar is in Lev. xiv. 4, 6, where we are told that Moses commanded the leper that was to be cleansed to make an offering of two sparrows, cedar-wood, wool dyed in scarlet, and hyssop ; and in ver. 49, 51, 52, the houses in which the lepers dwell are directed to he purified with the same materials. Again, in Num. xix. 6, Moses and Aaron are commanded to sacrifice a red hei fer : ' And the priest shall take cedar-wood, and hyssop, and scarlet.' As remarked by Lady Call cott (Scrip. Herbal, p. 92), ' The cedar was not a native of Egypt, nor could it have been procured in the desert without great difficulty ; but the juniper is most plentiful there, and takes deep root in the crevices of the rocks of Mount Sinai.' That some, at least, of the cedars of the ancients were a species of juniper is evident from the passages we have quoted ; the wood of most of them is more or less aromatic.

 

Another:

 

The name "ars" is applied to the Cedar of Lebanon by the Arabs in the hood. The term alerce, that is al-arz, applied by the Arabs to a coniferous plant, native of Mount Atlas, from alerce the English name larch is supposed to have been derived.

 

another:

 

*CEDRUS {Ktdpoc and KtSptc), the Cedar, as we commonly translate it. According to the best botanical writers, however, the neipoc of the Greeks and Cedrus of the Romans was a species of Juniper. The Cedar of Lebanon seems to have been but little known to the Greek and Roman writers. Theophrastus, according to Martyn, appears to speak of it in the ninth chapter of the fifth book of his History of Plants, where he says that the eedars grow to a great size in Syria, so large, in fact, that three men cannot encompass them. These large Syrian trees are probably the Cedars of Lebanon, which Martyn believes Theophrastus had only heard of, and which he took to be the same with the Lycian cedars, only larger ; for in the twelfth chapter of the third book, where he describes the Cedar particularly, he says the leaves are like those of Juniper, but more prickly; and adds that the berries are much alike...

...The Cedar of Lebanon, so celebrated in Scripture, is a Pine, and is hence named Pinus Cedrus by modern botanists. The nedpic of the medical authors is, according to Adams, the resin of the Juniper. Nicander calls it Keipow tutevdtc.

[Oded Kishony]

Brandmair and Greiner find that the samples of old varnish they tested seemed to be  4 parts' spruce' or larch resin to one part linseed oil. Greiner gives a recipe for a varnish at this ratio in his footnotes ( I am away from the workshop but will edit this post with a page reference later) A varnish at this ratio will need thinners of some kind to facilitate application and he suggest some kind of turpentine from the Kremer range.

 

So far I have not managed to make a convincing varnish myself at this ratio but that means little.  If we consider using turpentine as a solvent there are also other historically verifiable solvents we can use. Koen Padding talked of olio di sasso , olio di petri ie paraffin lamp oil and other texts would seem to imply that Rosemary oil was in common use in Northern Italy at Stradivari's time. Both lamp oil and Rosemary would extend brushing time in a lean oil varnish compared to turpentine but also some warm weather is required to dry this varnish due to the slow evaporating solvent.

 

 

There are several ways to skin this cat (to coin a phrase;-) As I've mentioned before there is some evidence that the Cremonese (at least del Gesu)  probably used a tincture as part of the varnish process. If this (alcohol) colored tincture contained some resin and was painted over a coat of  oil/resin varnish the result would look like a very lean varnish. 

 

In a way this is what happens when French polish is applied, some of the oil varnish (if it is the right kind) dissolves and fuses with the polish. Shellac was not the only resin used in French polishing.

 

Oded

[FredN]

 

 

Perhaps the mention of Herodotus of cedar oil being used on mummification?

 

Maybe this document gives a clue? (hit the page and search "cedar")

PISTACIA SPECIES IN RELATION TO THEIR USE AS VARNISH AND “INCENSE” (sntr) IN PHARAONIC EGYPT

 

Add to that-  the name Cedar is a confusing one in history, here are some excerpts:

 

...The term ' cedar' seems to have been as indefinite in ancient as in modern times. Now we find it applied to the wood of Yunipersis virginiana, which is red or pencil cedar ; and to that of J. Bermudiana or Bermuda cedar. J. oxycedrus yields the cedar of the north of Spain and south of France, but the term is also applied to many other woods, as to white cedar, that of Melia Azedarach ; and Indian cedar, that of Cedrela Toona

 

Another

 

...The earliest notice of the cedar is in Lev. xiv. 4, 6, where we are told that Moses commanded the leper that was to be cleansed to make an offering of two sparrows, cedar-wood, wool dyed in scarlet, and hyssop ; and in ver. 49, 51, 52, the houses in which the lepers dwell are directed to he purified with the same materials. Again, in Num. xix. 6, Moses and Aaron are commanded to sacrifice a red hei fer : ' And the priest shall take cedar-wood, and hyssop, and scarlet.' As remarked by Lady Call cott (Scrip. Herbal, p. 92), ' The cedar was not a native of Egypt, nor could it have been procured in the desert without great difficulty ; but the juniper is most plentiful there, and takes deep root in the crevices of the rocks of Mount Sinai.' That some, at least, of the cedars of the ancients were a species of juniper is evident from the passages we have quoted ; the wood of most of them is more or less aromatic.

 

Another:

 

The name "ars" is applied to the Cedar of Lebanon by the Arabs in the hood. The term alerce, that is al-arz, applied by the Arabs to a coniferous plant, native of Mount Atlas, from alerce the English name larch is supposed to have been derived.

 

another:

 

*CEDRUS {Ktdpoc and KtSptc), the Cedar, as we commonly translate it. According to the best botanical writers, however, the neipoc of the Greeks and Cedrus of the Romans was a species of Juniper. The Cedar of Lebanon seems to have been but little known to the Greek and Roman writers. Theophrastus, according to Martyn, appears to speak of it in the ninth chapter of the fifth book of his History of Plants, where he says that the eedars grow to a great size in Syria, so large, in fact, that three men cannot encompass them. These large Syrian trees are probably the Cedars of Lebanon, which Martyn believes Theophrastus had only heard of, and which he took to be the same with the Lycian cedars, only larger ; for in the twelfth chapter of the third book, where he describes the Cedar particularly, he says the leaves are like those of Juniper, but more prickly; and adds that the berries are much alike...

...The Cedar of Lebanon, so celebrated in Scripture, is a Pine, and is hence named Pinus Cedrus by modern botanists. The nedpic of the medical authors is, according to Adams, the resin of the Juniper. Nicander calls it Keipow tutevdtc.

 

 

Hi Carlo- thanks for the  info. Hope you've had a good sailing year.   fred

[Melvin Goldsmith]

In Post 90 of this thread I mentioned a recipe in Peter Greiner's footnotes in the excellent Stradivari Varnish book where he recreates a 4 parts colophony to 1 part linseed oil varnish. One of the most interesting fesatures of this recipe is that he uses Spruce resin to make the colophony. Anyone who has made colophony from European Spruce resin will be aware that this is not at all like the general colophony that is available on the market today which could come from  a mix of a whole range of global sources. 

[DonLeister]

Melvin, I take this to mean that the raw resin is cooked down to a harder and darker substance, colophony. Is the oil cooked also?

I collected some American red spruce resin once and cooked it , it made a great dark red brown colophony. It never made it into a varnish for some reason, I would have to check my notes. You have inspired me to try again. I will be near some spruce forests next week so I will come prepared.

I have been using a high resin varnish that works well with raw oil, using thinners of course.

[Jacob]

In Post 90 of this thread I mentioned a recipe in Peter Greiner's footnotes in the excellent Stradivari Varnish book where he recreates a 4 parts colophony to 1 part linseed oil varnish. One of the most interesting fesatures of this recipe is that he uses Spruce resin to make the colophony. Anyone who has made colophony from European Spruce resin will be aware that this is not at all like the general colophony that is available on the market today which could come from  a mix of a whole range of global sources. 

 

Melvin, do places like Kremer offer this? And what is it called? Isn't the Burgundy resin spruce resin?

[pbelin]

Kremer is someone one can really talk with, he knows about everything there's to know, and offers pretty much everything you should need…

And I get no commission for that…

[Melvin Goldsmith]

Melvin, do places like Kremer offer this? And what is it called? Isn't the Burgundy resin spruce resin?

 

Hi Jacob. I am not entirely sure that Burgundy is totally species specific. Kremer sells it as 'colophony of the European pine'. Recently however Kremer has started selling resin that they state is European/Norway spruce i.e.  picea excelsa.    http://www.kremer-pigmente.com/en/mediums--binders-und-glues/picea-excelsa-gum-62046.html

[Jacob]

Hi Jacob. I am not entirely sure that Burgundy is totally species specific. Kremer sells it as 'colophony of the European pine'. Recently however Kremer has started selling resin that they state is European/Norway spruce i.e.  picea excelsa.    http://www.kremer-pigmente.com/en/mediums--binders-und-glues/picea-excelsa-gum-62046.html

 

Thanks Melvin.

[Oded Kishony]

Hi Jacob. I am not entirely sure that Burgundy is totally species specific. Kremer sells it as 'colophony of the European pine'. Recently however Kremer has started selling resin that they state is European/Norway spruce i.e.  picea excelsa.    http://www.kremer-pigmente.com/en/mediums--binders-und-glues/picea-excelsa-gum-62046.html

Kremer is calling it a gum which implies that it is water soluble. A resin is not water soluble.

 

Oded 

[Michael_Molnar]

Kremer is calling it a gum which implies that it is water soluble. A resin is not water soluble.

 

Oded 

I don't recall reading that about gums. For example, I think gum copal is water insoluble. 

[Oded Kishony]

gum  

/gəm/

 

Noun

1. A viscous secretion of some trees and shrubs that hardens on drying but is soluble in water, and from which adhesives and other products...
2. The firm area of flesh around the roots of the teeth in the upper or lower jaw.

 

or

 

http://dictionary.reference.com/browse/gum

 

 

Oded

[fiddlecollector]

Copal just aquired that name along the line somewhere and it stuck . It is definitely a hard semi fossil resin of varying age that doesnt dissolve in water.

Though some mucilage will often come off it when boiled in water.

[Oded Kishony]

Yes it looks like some 'hard resins' are being referred to as 'gum', but as you can see the 'official' definition for gum is a water soluble resin.

 

Oded

[Michael_Molnar]

Lutherie is loaded with misused terminology. The issue is whether Picea Excelsa Gum follows the definition of Oded's dictionary, namely is it soluble. I really don't know. And like Oded I would have thought that it should be soluble.

 

I'm just the messenger who got shot. 

[Jacob]

Lutherie is loaded with misused terminology. The issue is whether Picea Excelsa Gum follows the definition of Oded's dictionary, namely is it soluble. I really don't know. And like Oded I would have thought that it should be soluble.

 

I'm just the messenger who got shot. 

 

Apart from that, "picea excelsa" is, as far as I know, not a legitimate species name any more - it's just plain old "picea abies".

[Jacob]

Hi Jacob. I am not entirely sure that Burgundy is totally species specific. Kremer sells it as 'colophony of the European pine'. Recently however Kremer has started selling resin that they state is European/Norway spruce i.e.  picea excelsa.    http://www.kremer-pigmente.com/en/mediums--binders-und-glues/picea-excelsa-gum-62046.html

 

Melvin, isn't "gum" different from "resin". Surely that Kremer's product, which cooked down, will produce a markedly smaller quantity of actual resin. If you feel like elaborating I'd be most interested to know how you find this resin different from "ordinary" resin as far as varnish making is concerned.

[fiddlecollector]

If the Kremer stuff is just spruce oleoresin its rather expensive . Go to your friendly local wood yard in the UK and ask for all the knotty whitewood offcuts that are usually oozing resin in warm weather.

[Julian Cossmann Cooke]

I know this thread has ventured hither and yon since the original posting.  So I think the following question also fits under the original heading of varnish making questions for chemists.

 

My reading as well as my own experimentation has led me to wonder about the balsam found in most propolis.  Knopf suggests in his book Der Cremoneser Lack; Eine Studie ueber Geigenlack-Untersuchungen (roughly translated as The Cremonese Varnish;  A Study of Violin Varnish Research) that lower balsam content propolis is better suited to making violin varnish and even includes a table showing propolis samples from a variety of sources around the world and their relative balsam content.  That's interesting, but he doesn't go into why balsam as found in propolis may be problematic.  Does it hinder drying?  Does it keep propolis from mixing with various solvents/oils?  Does it contribute to eventual hardening of varnish and thereby stand in the way of a more flexible varnish?

 

Other threads do discuss balsam in the context of copaiba balsam etc. but in this case I am interested in balsam as it occurs in propolis and interacts with the other components of propolis.

 

Thanks in advance to the chemists -- amateur and professional -- among us!

[Oded Kishony]

If the Kremer stuff is just spruce oleoresin its rather expensive . Go to your friendly local wood yard in the UK and ask for all the knotty whitewood offcuts that are usually oozing resin in warm weather.

 

http://www.wikihow.com/Tap-a-Pine-Tree

 

or collecting fir sap http://www.infor.ca/educational_resources2

 

 

Oded

[David Burgess]

gum  

/gəm/

 

Noun

1. A viscous secretion of some trees and shrubs that hardens on drying but is soluble in water, and from which adhesives and other products...
2. The firm area of flesh around the roots of the teeth in the upper or lower jaw.

 

or

 

http://dictionary.reference.com/browse/gum

 

 

Oded

 

Then what the heck is "gum spirits of turpentine", which seens to be a turpentine trade accepted term. Neither the tree exudate, or the distillation product likes to mix with water very well.

 

Dictionaries can lead us astray sometimes, I think. The people who wrote them may know less about a specialized area than we do.

[captainhook]

I can't answer Julian's question, but "gum" has been used somewhat interchangeably with "resin" by the varnish industry for a long time. A good example is ester gum, which is rosin cooked with glycerol ( and not a bad resin, in my experience). It has nothing to do with lutherie.

[fiddlecollector]

Gums are scientifically polysaccharide materials ,based on plant sugars/starches.  Resins are plant oleoresins or derivatives of them ,(including animal resin like shellac for instrument makers)  and tar/pitch from heat treatment of plant resins or wood.