Sign in to follow this  
fiddlefaddle

Varnish coloration

Recommended Posts

quote:


Originally posted by:
Mike_Danielson

John, what do you mean "and the zinc will take powdered alizarin (not the lake) to redden the resin considerably." Alizarin crimson as I use it is a lake, purchased from Daniel Smith artists supply. It is very finely ground and is dispersed into the varnish (not dissolved) Where does your alizarin come from? You seem to imply that there is a reaction between the zinc and the alizarin. Mike D

Alizarin crimson oil paint uses the aluminum lake. I meant pure alizarin as from a chemical supply, before combination with a metal mordant. I suppose alcohol extract of madder would work too, better have a fair amount, and it is expensive. Alizarin is cheap if you have a chemical house contact. Try GFS chemicals and tell them you are a violin-maker and not a terrorist. I have dealt with them for ages, and they are very accomodating. (They used to be located here in Columbus, OH but now ship from foreign states.)

Share this post


Link to post
Share on other sites

You have a point Fry or somebody reccomended soaking the violin in

linseed oil which basically ruins the violin for future restoration

as hide glue will not hold a crack after its been soaked in Linseed

oil, anyway I reccomend a la Sacconi I think a clear undercoat and

possibly clear overcoat to the coloured centre coats. I don't have

any of the violins I varnished around, lately ive completely quit

revarnishing, and only use my varnish for touch up work, for

instance if a violins varnish is flaking off along the grain and in

danger of completely dissappearing I put a thin surface coat of my

varnish, to help hold together whats left of the original varnish

and slowing the flaking of process,Melving, I do have a scrap

piece of a top I varnished 20yrs ago with my Fry formula varnish,

its a healthy orange brown colour, Ill try to take apicture in

sunlight to show the amazing refraction properties of nitric acid

varnish, Ive never loaded a picture here before though, I may need

help, sincerely Lyndon

Share this post


Link to post
Share on other sites

perhaps I am showing my ignorance here, but it seems to me that Fry's method differs from Fulton, in that he did not create a resin, which Fulton then dissolved in an oil, but simply oxidized the terpene, and called that a varnish. It is not illogical that this avoids the drying problem

Taylor uses Dammar, (oxidized) then dissolve that in boiled linseed oil. This is really a Fulton Varnish ( with Dammar rather than colophony).

So, I am saying that Taylors process more resembles The Fulton method, except that he uses dammar.

Please correct my observations if they are incorrect.

I am enjoying this debate immensely.

Share this post


Link to post
Share on other sites

Manfio,

I think this is a great color. Do you do the nitrite first and then fume? Do you find it necessary to neutralize the surface prior to varnishing. I have seen repeated evidence of a "halo" of lightened color effect in the area of the plate as it curves back up to the purfling...in an area where one would expect the opposite. I see no evidence of this in your picture. Ever seen it?

What goes on top of the color? If you want to share that....

Thanks.

Joe

Share this post


Link to post
Share on other sites

There is a laundry list of methods to color the varnish. If one suspends the questions about historical precedents for the moments, we have pigments, nitric varnishes, processed rosinates ( ie Michaelman/Ravitan), rosin soaps, madder and alizarin color concentrates and various combinations of the list. Many of these methods do not show a particulate under UV examination. They each vary widely in appearance, color stability, and transparency. The issue remains one of choosing the right tools for the job.

On we go,

Joe

Share this post


Link to post
Share on other sites

Fiddle faddle, Frys varnish involves dissolving colophony in turp

and adding 25-33%linseed oil, my formula is 60part dammar, 40 parts

colophony, 25 parts linseed oil and about 200 parts pure gum

turpentine, if that still exists!! sincerely Lyndon

Share this post


Link to post
Share on other sites

I was thinking about what Manfio said. He has been very open in reporting his method of finishing--the use of nitrite and fuming with ammonia as two steps in the process to brown the wood. In my opinion, the process must start with getting the bare wood in a brown state. We know that exposure to the sun is a slow browning process with inherent dangers to the instrument as the seams open up from excessive heating.

What if the masters used horse urine to accelerate the browning process? It would contain ammonia and nitrites along with other stuff (some probably brown colored). I would presume you would seal the spruce first before an application of urine. Any historic data on this?

Mike D

Share this post


Link to post
Share on other sites

I found it thanks,

Yes, I've got my sodium nitrite from a chemical supply, sodium nitrite is cheaper and more easy to buy than potassium nitrite.

Yes, the turpentine with oil works, I'm using my oil varnish (2 parts oil, 1 part rosin, one part mastic) diluted in turpentine to help the tanning process too.

My whole process, that I may have already mentioned here is the following:

I start with a somewhat dark coloured wood, this way:

Sun tanning,

strong tea,

4% potassium nitrite in water followed by exposition to direct sun (6 hours), perhaps 2 times that (test in samples first, take care with the top, it can get blotched),

some of my oil varnish (the recipe in Biblioteca Marciana, Venezia, also on Baese's book: 2 parts oil, one part colophony, one part mastic) diluted in turpentine, 2 coats,

strong tea,

light glue sizing with a bit of alum,

stain (harmell)

more tea,

light fumigation with amonia.

If it gets too dark in the middle stop the process. It's a bit intuitive, like cooking (I love cooking...).

After all that the wood will have a strong cinamon colour and the wavings will be darker. This method would not be used by people with a faultless and very clean work, such as Darnton or Burgess, but it's good for a "Guarneriesque" work as mine.

Ground: my oil varnish (2 parts oil, one part colphony, one part mastic) can send you the recipe) in a paste with tripoli rubbed into the wood (don't leave it build up, don't leave it thick anyway). I take off the excess with a rag with kerosene, apply a bit more of my oil varnish and rub it over the wood to develop a very thin, but quite reflexive surface. This ground will penetrate a bit in the wood and that will make the contrast in the flames more visible, I think. The penetration in the wood will be stoped in different depths of the wood (this process had already started with the aplication of my thinned oil varnish) causing the holografic and tridimensional effect.

Varnish:

one coat of Padding's "Doratura Cremonese" thinned with Kerosene and heavily coloured with asphalt (roof tar) and Alizarin Crimson. The kerosene/pigments thinner will be very very concentrated, a residue will form in the bottom of the jar, so filter it;

two coats of Padding's "Doraratura Rossa" used the same way. Used 1500 Micro Mesh betwen the coats, as well as tripoli. Polished with tripoli and polish

Share this post


Link to post
Share on other sites

Michelman was the one to recommend linseed oil saturation of the wood. He was thinking of displacing water. He was not a violin maker, but a commercial paint chemist who worked in Cincinnati, Ohio. His interest in violin varnishes may have come through his wife, an amateur violinist.

Share this post


Link to post
Share on other sites

I am still testing the Fry type varnishes and get good results

 

I am able to get a dark colored varnish without any pigments

and I think that I get a nice color.

Please look at the two pictures of the same sample and tell me

what you think about it.  

One picture was taken with the camera using normal bulb lights and

the other picture was made with the scanner.  The original

color of the sample is between the two pictures.  Not too red,

Not too brown...

Still waiting for other pictures....  Be courageous

Richard

Share this post


Link to post
Share on other sites

quote:


Originally posted by:
Mike_Danielson
I was

thinking about what Manfio said. He has been very open in reporting

his method of finishing--the use of nitrite and fuming with ammonia

as two steps in the process to brown the wood. In my opinion, the

process must start with getting the bare wood in a brown state. We

know that exposure to the sun is a slow browning process with

inherent dangers to the instrument as the seams open up from

excessive heating. What if the masters used horse urine to

accelerate the browning process? It would contain ammonia and

nitrites along with other stuff (some probably brown colored). I

would presume you would seal the spruce first before an application

of urine. Any historic data on this? Mike D

What are you thinking about when you say: "It would contain ammonia

and nitrites along with other stuff (some probably brown

colored)."

Please elaborate about the other stuff...  

Richard

Share this post


Link to post
Share on other sites

Urine is going to be worked on by bacteria (fermented); so there will be a lot of different chemicals in various states of oxidation. Urine contains proteins, uric acid, electrolytes (I really need to look up the composition in detail). The nitrogenous components will be in different states of oxidation; hence, the suggestion of nitrites and ammonia, and the other stuff.

Perhaps another source of stain (preservative?) is the fermented juice or liquid that comes out of a manure pile--it has the right color.

Anyone know the history of using this stuff for wood staining, dyeing, preservation?

Mike D

Share this post


Link to post
Share on other sites

quote:


Originally posted by:
rb_quebec

I am still testing the Fry type varnishes and get good results

... .

Richard

Nice work, Richard. How many coats and is this on a ground or bare wood. I find that I cannot let this varnish soak into bare wood or it will look dirty brown.

Share this post


Link to post
Share on other sites

Fry made a convincing argument that the luthiers of Cremona had the materials and knowledge to make this kind of varnish. Whether they did is the subject of another debate.

Nevertheless, does anyone have information refuting Fry?

Share this post


Link to post
Share on other sites

Refuting Fry? Never heard anything other than that some say it does not dry. Others say it gets hard. I would like to know what the actual hardness is, and how the entire varnish was made, with oils etc. I once opened a site that had to do with old Italian varnished "analysed." What was found were a lot of metals, just what you would expect from driers. Yet, many people still avoid metalic driers or say they are not good. (It was by a German author, forget where I saw it.)

The big trouble in varnish discussions is that whatever evidence IS out there is never collected together. For example, has nitrogen been found in ancient varnish samples? If there are samples available, this should not be at all hard to do. One does not expect any nitrogen in natural resins or oils.

Share this post


Link to post
Share on other sites

Thank you Joe! The process is the one fidlefaddle mentioned. The colour is from Alizarin Crimson in oil (from Kremer) plus betumen (roof tar), the colour is quite concentrated and it works well with the darkened wood, it would be impossible to apply such highly coloured varnish over light wood, I think.

The Marciana varnish (2 parts oil, one part mastic, one part colophony) is quite reflexive, it penetrates a bit in the wood with the tripoli paste, creating the hollografic effect. I would like to test your varnishes one day. This is the back of the same viola:

1437770048_6bcfe0ced9.jpg

Share this post


Link to post
Share on other sites

FWIW Condax found nitrogen. This is in section 4.4 of Ferbose' draft, titled "Proteinaceous Material". Not really useful without knowing how completely alcohol extraction would be expected to remove resins (such as those produced by the Fry process) from a varnish sample.

"Condax and coworkers reported that the alcohol-insoluble fraction of antique Italian finishes contained 7% nitrogen"

Incidentally, Condax wrote in the CAS Newsletter (Journal?) in 1966 about comparing Fry and Michelman varnish to old Italian varnish, it would be interesting to see what he had to say.

Share this post


Link to post
Share on other sites

Thanks Andre. I know that Condax used proteins for interlayers. Oddly, he did not use them in emulsions; at least not in the report I published some time ago. (David Fix's transcription) Maybe my memory is faulty.

I would not expect alcohol to extract any resins because they have lost their identities in the polymerizations with the oils. If old varnishes are largely alcohol soluable, then what disolved would probably be unlike what resins went into it; at least in my view.

I was thinking of mass spectrometry to count every atom.

Share this post


Link to post
Share on other sites

quote:


Originally posted by:
Johnmasters

Refuting Fry? Never heard anything other than that some say it does not dry.

... .


No, John. Wrong Issue. I was talking about the historical evidence Fry gives for nitric acid.

The drying issue is a horse of another color. Or should I say a varnish of another color. (grins)

Share this post


Link to post
Share on other sites

Mike D.,

Walnut logs used to be buried in the manure pile over the winter to darken the (white) sap wood and make the color more even. I never have heard anything similar about maple or spruce.

Joe

Share this post


Link to post
Share on other sites

You guys ever read anything by the Canadian author, Robertson Davies? I think it is in his book "The Lyre of Orpheus" that the gypsy woman (mother of Maria Teotoky, one of the major characters) fixes famous old violins that are worn out from overplaying. She takes them apart and puts them into a manure pile (presumably dry) for a few months to restore their vigor.

I bet there is no truth in this--just what a famous author has done to add some interest to his story.

Mike D

Share this post


Link to post
Share on other sites

quote:


Originally posted by:
Michael_Molnar

quote:


Originally posted by:
Johnmasters

Refuting Fry? Never heard anything other than that some say it does not dry. ... .

No, John. Wrong Issue. I was talking about the historical evidence Fry gives for nitric acid.

The drying issue is a horse of another color. Or should I say a varnish of another color. (grins)

Mike, because of your interest in ancient mindsets, you could consider the alchemist's mind. "I want my varnish to have the properties of gold." The only way to make gold liquid and to dissolve it in varnish is to use aqua regia. OOPs, have an excess of nitric acid here. You can forget the other acid, boil it off. I don't know if gold would combine with any bonds in the tree sap or not. Perhaps just precipitates out like other junk. No matter.

Could this have led to an initial experiment to nitrate resins? Just a guess, but a possible link to a method; one that should appeal to your interest in ancient thinking.

Share this post


Link to post
Share on other sites

Quote John,

"Mike, because of your interest in ancient mindsets, you could consider the alchemist's mind. "I want my varnish to have the properties of gold." The only way to make gold liquid and to dissolve it in varnish is to use aqua regia. OOPs, have an excess of nitric acid here. You can forget the other acid, boil it off. I don't know if gold would combine with any bonds in the tree sap or not. Perhaps just precipitates out like other junk. No matter.

Could this have led to an initial experiment to nitrate resins? Just a guess, but a possible link to a method; one that should appeal to your interest in ancient thinking."

I have to agree with John. Gold was a trade secret in Venetian glass' red color. (it is still used in the best Venetian glasswork) The temptation to use the salt of gold in varnishes must have been overwhelming.

Mike C

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
Sign in to follow this  

  • Recently Browsing   0 members

    No registered users viewing this page.