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Weak Rosin/Linseed oil varnish. J.Michelman recipe failed trial.


David A.T.
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Hello Maestronet Experts,

I finished one coat of linseedoil/rosin/Zn/Al/Madder self made varnish 2 weeks ago. It is 'inspired' by J Michelman recreations. Varnish is still 'sticky' when the hand is left few seconds on the instrument. It looks dry when touched very fast. It is probably the last coat I will do.

While cleaning the neck fingerboard surface one drop of water went on varnish surface and seems to have removed the last layer after few seconds.

Is it normal that varnish is so weak? Any clue about what was missing in the varnish? (Maybe Just need to wait more Drying time : few weeks more, or change the receip adding other resin, more mineral...)

 

Thank you for your tips if you had such experience and have a nice day!

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  • David A.T. changed the title to Weak Rosin/Linseed oil varnish.
On 2/27/2021 at 3:17 AM, David A.T. said:

Hello Maestronet Experts,

I finished one coat of linseedoil/rosin/Zn/Al/Madder self made varnish 2 weeks ago. It is 'inspired' by J Michelman recreations. Varnish is still 'sticky' when the hand is left few seconds on the instrument. It looks dry when touched very fast. It is probably the last coat I will do.

While cleaning the neck fingerboard surface one drop of water went on varnish surface and seems to have removed the last layer after few seconds.

Is it normal that varnish is so weak? Any clue about what was missing in the varnish? (Maybe Just need to wait more Drying time : few weeks more, or change the receip adding other resin, more mineral...)

 

Thank you for your tips if you had such experience and have a nice day!

More details please.  What kind of linseed oil.  Cooked resin?  How much zinc and alum? 

Application thickness?  What ground?

I'll stay tuned aka Optical Mike...

on we go

Joe

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Welll...... lacking any other information from OP, but calling on my own experience with alchemy, I'll offer this:

For a time I was headed down an alchemical path that resulted in utterly brilliant varnish. Stunning color, shine, flare, flash, fame, riches, glory ... it was all there. Well, except it was water soluble even after it dried on the instrument.

I won't disclose all the gory details, but it was fundamentally a Michelman / precipitated-particulate-pigment sort of process. The problem is that I left water soluble minerals in the final varnish because I didn't have a way to remove them. Most likely, the water soluble mineral was NaCl because I used sodium carbonate and calcium chloride to make the pigment (one of the products of that reaction is sodium chloride).

Anyway, the OP might look at the reaction equations to determine what water soluble minerals are left in the final product, and then figure out how to eliminate those minerals.

 

(Edit: I just re-read the OP's post, and I feel obligated to disclose that I'm not an Expert.)

Edited by ScotPiper
For giggles.
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There are a variety of reasons why a varnish may react to water. Water soluble caput mortuum (alchemy lingo for unwanted waste products) is one of them. For example, potassium rosinate is precipitated with zinc sulfate (a salt: note that dissolved salts express as their distinct anions and cations) - the zinc displaces the potassium ion on the abietic acid chain, forming insoluble zinc abietate (rosinate). The potassium bonds with the free sulfate ion forming potassium sulfate, soluble in water. 

This is precisely why Michelman encourages thorough rinsing of the rosinate, several times. If you fail to do this you will have an inferior product. 

If you use chloride salts, eg ferric chloride for the production of brown rosinate, a similar thing occurs- the caput mortuum is potassium chloride, a known substitute for table salt (NaCl) and soluble in water. 

Inexpert curing and application can also result in non-resistent varnishes. 

I am not a chemist. I work with chemists. I am, at best, an alchemist. The Michelman processes are simple, but they are not easy. Remember the man was a master level chemist with extensive laboratory training and resources. If you are not prepared to devote significant time, care, and resources to operating at a professional level of laboratory hygiene, you will fail. 

A simpler way to produce a good varnish, though not as versatile, is to cook venice, larch, or silver fir turpentine at 200C for as much as 200 hours in order to arrive at a good color. Cook this into good quality cold pressed raw linseed oil that has been processed to remove mucilage (also water soluble). Adjust color with earth pigments or naturally occurring anthraquinones. 

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2 hours ago, MANFIO said:

A sticky varnish after two weeks of application is a problem too. And if it is water soluble, it may be sweat soluble too.

A sticky varnish after two days would be a bad sign.

on we go,

Joe

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Hello,

 

First I thank you all for considering seriously my question.

The receip follow the book proportion, except for the madder for which I increased the weigth of madder root x5 to produce the madder concentrate.

 

Ground was a thin layer of potassium silicate + calcium sulfate (applied where I found minors scratches). Then few drop of cooked linseed oil that I bought ready made. the oil has a  little red color .

then the rosin was prepared with 2 receipt, 1st with Alun to get a Yellow varnish, 2nd with Zn (and little Fe) and Madder to get the Red varnish. I followed the proportions of the book, I will not reproduce the deails of the reciep, it is also in the article - but maybe due to measurement tools I was 1/10 inaccurate (when I need 10 grams,I don't know if it is 9.5 or 10. 5 + innacuary of the measure).

the rosin , once dried looks that way

IMG_5278.thumb.JPG.0f5c22deb3b1387dd8ccac165304c2c7.JPG

 I did not made the operation to wash the Rosin ! (comments from ScotPiper  and JacksonMaberry) - It was described in the book but I though the remaining Salts would stay in the filter after  the dilution with oil & turpentine. Maybe I underestimated the effect of these salts on the finished varnish.

rosin was then diluted in Turpentine & Oil with following proportions  for the red varnish:

 

2g MadderBrownRosinate

5cc Turpentine

3cc Linseed Oil

The red varnish looks very deep red/dark in the bottle.

I applied 4 layer of the 1st varnish (yellow/clear) then 2 layers of the red one, waiting 5-7 days between layers. Note that when ambiant humidity was below 30% the varnish dry much faster.

the varnish looks very little red, and looks even yellow under the sun.... 

I fear to put too many coats, I though 2 red coats are enough. Maybe a last modified coat could react or protect from water?

20210214_105035.thumb.jpg.3cd435d95e92223e5a890f6ccac46f1c.jpg

 

Thank you  JacksonMaberry for your article - It was not easy to read many many many times the book from chapters to chapters on my Kindle and summarize it on one page for my work. I see this is what you just greatly did in this article. I will read it carefully.

 

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18 hours ago, ScotPiper said:

Welll...... lacking any other information from OP, but calling on my own experience with alchemy, I'll offer this:

For a time I was headed down an alchemical path that resulted in utterly brilliant varnish. Stunning color, shine, flare, flash, fame, riches, glory ... it was all there. Well, except it was water soluble even after it dried on the instrument.

I won't disclose all the gory details, but it was fundamentally a Michelman / precipitated-particulate-pigment sort of process. The problem is that I left water soluble minerals in the final varnish because I didn't have a way to remove them. Most likely, the water soluble mineral was NaCl because I used sodium carbonate and calcium chloride to make the pigment (one of the products of that reaction is sodium chloride).

Anyway, the OP might look at the reaction equations to determine what water soluble minerals are left in the final product, and then figure out how to eliminate those minerals.

 

(Edit: I just re-read the OP's post, and I feel obligated to disclose that I'm not an Expert.)

In general this is an issue with this and similar procedures.   Excess or unreacted metal salts are hydrophilic. The issue with using an excess of Cobalt drier is similar.

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17 hours ago, joerobson said:

In general this is an issue with this and similar procedures.   Excess or unreacted metal salts are hydrophilic. The issue with using an excess of Cobalt drier is similar.

I have come to the conclusion that I tend to use applications in excess which is indeed counterproductive if not harmful. So, I now back off by either reducing concentrations, or use methods that mop up the excess. 
 

There is a rule about avoiding too much of a good thing. :)

Do all things in moderation.

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20 hours ago, David A.T. said:

The receip follow the book proportion...

The Michelman recipe for varnish is a cold-mix, not cooked.  I have never tried a cold-mix varnish, strongly influenced by what I've seen of cold-mix results... extreme alligator cracking (more like icebergs floating on a sea of wood), extreme wear, and the like.  Somewhere between the included salts and non-cooked varnish, I think you'll find the problem.

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10 minutes ago, Don Noon said:

The Michelman recipe for varnish is a cold-mix, not cooked.  I have never tried a cold-mix varnish, strongly influenced by what I've seen of cold-mix results... extreme alligator cracking (more like icebergs floating on a sea of wood), extreme wear, and the like.  Somewhere between the included salts and non-cooked varnish, I think you'll find the problem.

Precisely, all of which is covered in my article.

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However perfect you wash that precipitate to remove the salt byproducts, the vulnerability of the Michelman varnish to moisture won't go away. Believe me JacksonM, I tried!!

The reason is that the very core of the varnish - the metal rosinate -  is in itself a salt. No longer soluble in water, but still not resistant enough to moisture.

(I know I've bragged about this before:

In all other aspects, I loved it. If it is not touched - at least not by my skin and by some of my customers skin, as I learned - it ages beautifully. I.e. no alligatoring.

I don't antique my instruments. But if I did, I might actually use Michelmans varnish. Because then them vulnerable places would be bare and maybe frenchpolished already! But at that medium stage; when the varnish is all tacky and dirty at the shoulder etc., is just awful.)

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11 minutes ago, Salve Håkedal said:

However perfect you wash that precipitate to remove the salt byproducts, the vulnerability of the Michelman varnish to moisture won't go away. Believe me JacksonM, I tried!!

The reason is that the very core of the varnish - the metal rosinate -  is in itself a salt. No longer soluble in water, but still not resistant enough to moisture.

(I know I've bragged about this before:

In all other aspects, I loved it. If it is not touched - at least not by my skin and by some of my customers skin, as I learned - it ages beautifully. I.e. no alligatoring.

I don't antique my instruments. But if I did, I might actually use Michelmans varnish. Because then them vulnerable places would be bare and maybe frenchpolished already! But at that medium stage; when the varnish is all tacky and dirty at the shoulder etc., is just awful.)

Salve, with respect, you clearly do not understand the relevant chemistry. Your assertion that a properly washed rosinate "is in itself a salt" is false. A salt is an ionic assembly of cations and anions. Rosinate, or metal abietate, is a molecule of abietic acid to which a metal ion has been fused with a bond much stronger than the ionic bonds present in salts. 

I am sorry that you have had difficulty with rosinates, but it is clearly due to your inability to properly prepare them and their relevant varnishes. I suggest you read my paper and try again. 

If you have any doubts, I will gladly film a video of me attacking my varnish with water, saliva, sweat, acids, bases, solvents, and the like. My varnish simply doesn't have the problems you describe.

 

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27 minutes ago, JacksonMaberry said:

 

 

May I ask you if my pink dried rosinate on the above pic looks as it should look?

Are the small white particles all around the salts to remove?

I may restart some processes with other colors

 

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8 minutes ago, Salve Håkedal said:

If that's true, I'm really impressed. How old are your Michelman varnished instruments?

The oldest is five years. I'm sorry to have come off as combative: I am very protective of Michelman's legacy because his work is so poorly understood. His rosinate science is perfect. His varnishmaking was flawed. If you combine Michelman's rosinate preparations with JG McIntosh's method of production cooked rosinate varnish and are fastidious about careful and correct laboratory technique, you will not fail.

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11 minutes ago, David A.T. said:

May I ask you if my pink dried rosinate on the above pic looks as it should look?

Are the small white particles all around the salts to remove?

I may restart some processes with other colors

 

The white flecks are known as efflorescence, a phenomenon whereby salts recrystallize as water evaporates. If you have this problem, your varnish will fail. You must wash the rosinate more thoroughly. 

Also, the color intensity of your red rosinate is not very strong. My paper will set you up for success. Also, I don't recommend applying red varnish first. Ground the instrument, apply brown varnish, and add red in later coats. 

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1 hour ago, JacksonMaberry said:

Salve, with respect, you clearly do not understand the relevant chemistry. Your assertion that a properly washed rosinate "is in itself a salt" is false. A salt is an ionic assembly of cations and anions. Rosinate, or metal abietate, is a molecule of abietic acid to which a metal ion has been fused with a bond much stronger than the ionic bonds present in salts. 

I am sorry that you have had difficulty with rosinates, but it is clearly due to your inability to properly prepare them and their relevant varnishes. I suggest you read my paper and try again. 

If you have any doubts, I will gladly film a video of me attacking my varnish with water, saliva, sweat, acids, bases, solvents, and the like. My varnish simply doesn't have the problems you describe.

 

Yeah, definitely want to see a test to failure video. Hopefully myth buster style where the final test has no hope of survival and guarantees a fire ball ending. :P

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  • David A.T. changed the title to Weak Rosin/Linseed oil varnish. J.Michelman recipe failed trial.

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