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Julian Cossmann Cooke

Spirit Varnish for the Convinced and the Curious

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On 10/8/2019 at 10:53 PM, jezzupe said:

 

If one wants to increase the abrasion and chip resistance of shellac,a"hard shellac' can be made by adding some sodium hydroxide and or Drano crystals 

 

 

 

Is the purpose of the Drano to dissolve the cat hair that has found its way into the shellac?  :lol:

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I just put some {about a teaspoon} in a doubled coffee filter to make a "drano teabag" and then simply soak it for about an hour or less in the shellac  There may be some more scientific way,

I'm not sure what the long term effects on the film or coloration would be, but it does seem to alter the shellac and make the film more abrasion resistant.

It is not a "go to recipe" for me for instruments,mostly something I've used on furniture tops, learned from an old timer furniture guy long ago, but It may be something I;d experiment around with more.

But honestly I pretty much use shellac as a sealer at this point, when I use it, so I'm not too concerned with making a 'system" out of it.

 

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Here I have a question for those who are regularly using spirit varnish.

How to know that the varnish is dry enough for the next layer?

(Or how to be sure that the varnish doesn't crack after a while?)

 

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1 hour ago, Andreas Preuss said:

Here I have a question for those who are regularly using spirit varnish.

How to know that the varnish is dry enough for the next layer?

(Or how to be sure that the varnish doesn't crack after a while?)

 

Great question, Andreas.  I wish I could offer some science here in the way of an answer backed by some measurables.  But I can't -- though others may, of course.  I think the answer varies with the recipe, based on my experience with a traditional 1704 and the local pine resin concoction with which I am experimenting.  The former dries to the touch quickly enough that I could get 10 coats on in a day if I was diligent about minding the clock.  I have used 1704 and air dried it -- no UV tent -- within and hour.  My test was simply that it dried to the touch.  In the case of the pine resin varnish, I might get four coats on in a day, drying in the UV tent between coats.  Again, whether it was dry to the touch has been my test.

A caveat: a colleague was visiting yesterday and she pointed to tiny cracks in the pine resin varnish.  I need to look with magnification because I could not distinguish any cracks with the naked eye. (I'll report later today on what I find when I get out to the shop and don my dork goggles.)  If there are cracks, that may suggest inadequate drying between coats or some peculiar quality of the pine resin.  Again, others may weigh in with clarification -- Joe, where are you, my friend?

I have not experienced any cracking with 1704, probably thanks in part to the wax from the seedlac and the plasticity offered by the elemi, and that's after four years in the case of a couple of instruments that have not yet sold.

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15 hours ago, Julian Cossmann Cooke said:

Great question, Andreas.  I wish I could offer some science here in the way of an answer backed by some measurables.  But I can't -- though others may, of course.  I think the answer varies with the recipe, based on my experience with a traditional 1704 and the local pine resin concoction with which I am experimenting.  The former dries to the touch quickly enough that I could get 10 coats on in a day if I was diligent about minding

the clock.  I have used 1704 and air dried it -- no UV tent -- within and hour.  My test was simply that it dried to the touch.  In the case of the pine resin varnish, I might get four coats on in a day, drying in the UV tent between coats.  Again, whether it was dry to the touch has been my test.

A caveat: a colleague was visiting yesterday and she pointed to tiny cracks in the pine resin varnish.  I need to look with magnification because I could not distinguish any cracks with the naked eye. (I'll report later today on what I find when I get out to the shop and don my dork goggles.)  If there are cracks, that may suggest inadequate drying between coats or some peculiar quality of the pine resin.  Again, others may weigh in with clarification -- Joe, where are you, my friend?

I have not experienced any cracking with 1704, probably thanks in part to the wax from the seedlac and the plasticity offered by the elemi, and that's after four years in the case of a couple of instruments that have not yet sold.

It would be interesting in this thread to collect some exerience data. I find it for example interesting that 1704 seems to have a lower tendency for cracking. 

Secondly, if the varnish cracks, what to do?  Long ago this happened to me and I tried to polish it out just discovering that it .would eventually reappear. In this context I suspect that it depends a little on the polish ingredients as well. 

15 hours ago, Julian Cossmann Cooke said:

The former dries to the touch quickly enough that I could get 10 coats on in a day

How thinly do you apply it? 

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For some years I've used a varnish made of Ruby Shellac and Mastic (5+1). Ruby Shellac is dewaxed. I have only seen cracking on one instrument. And only adjacent to the brigde feet. Interestingly, this instrument has exceptionally light and soft spruce. So I expect the brigde feet to make depressions in the top wood rather fast, and the craking may be the first signs of that?

This varnish is rather hard and resistant. The Shellac probably dominates its properties. I've tried a larger proportion of Mastic, but did not like it, as it seemed to affect the drying time appreaciably. Of course: drying time is also dependent on the amount of solvent as well as the Shellac/Mastix ratio. I mix around 1 part solid matter with 3 - 4 parts alcohol. Thinner than that would require an unpleasant number of applications.

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13 hours ago, Andreas Preuss said:

It would be interesting in this thread to collect some exerience data. I find it for example interesting that 1704 seems to have a lower tendency for cracking. 

Secondly, if the varnish cracks, what to do?  Long ago this happened to me and I tried to polish it out just discovering that it .would eventually reappear. In this context I suspect that it depends a little on the polish ingredients as well. 

How thinly do you apply it? 

24-30 coats of 1704, slightly less so far with the pine resin spirit.  I'm not a big fan of so many coats from a workload standpoint.  On the other hand, at 1-2 minutes per coat, we're talking a maximum of an hour per instrument.  And the trade-off, in my view, is that I have greater control over the development of the color.

Whether the thinness of the coats has something to do with the absence of cracking, I don't know.

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On 11/26/2019 at 3:40 AM, Andreas Preuss said:

The beauty of 1704.

No additives.

The ground I used simply enhanced the contrast of the flames.

 

image.jpeg

1704 IS hard to beat -- in its results and its straightforward recipe.  Which recipe do you use, Andreas?  In fact, if folks have 1704 recipes they would like to share, it might be interesting to see how they vary.

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When working with a spirit varnish like 1704, is it better to use straight wax-free shellac instead of seedlac for the first few coats to increase adhesion for later coats?  Then switch to seedlac for final coats?

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On 12/24/2019 at 8:57 AM, Loco Luthier said:

When working with a spirit varnish like 1704, is it better to use straight wax-free shellac instead of seedlac for the first few coats to increase adhesion for later coats?  Then switch to seedlac for final coats?

I have used dewaxed shellac as a filler and then put the seedlac-based 1704 recipe over it without any adhesion problems.  That said, I have read (caution: reading can be harmful to your making) that adhesion is aided by two coats containing some quantity of the same ingredient.  If I am not mistaken, this was in reference to using propolis in both the ground and the varnish.  But then propolis itself is a somewhat controversial substance and I don't know in the above instance whether the propolis was dewaxed before use.  Perhaps it was wax-to-wax adhesion to which the book was referring -- which was written by a German and the Germans had notoriously bad experience with propolis.  Even dewaxed propolis -- like dewaxed shellac -- still has some wax remaining.  But now I ramble...

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Just found this recently. I think it is worth mentioning it here, though it is n French:

its a database on varnish recipes and the link below connects to lust of recorded spirit varnish recipes.

https://vernix.philharmoniedeparis.fr/vernix/infodoc/Ged/Search.aspx?searchExpression=idesia[thesaurus%3aIFD_VERNIX%2c+form%3a+0%2cautopostage%3a-1]%3d"LEXICON_00000020"&searchExpressionLabel=Vernis+%u00e0+l'alcool

 

 

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Hiya, all. 
 

I wonder if someone has compiled a reference to identify the relative rate of solubility, in ethanol, of the various resins we use.
 

Seedlac, in my experience, has a low rate of solubility - it takes a while to dissolve (which means, also, that subsequent varnish layers don’t dissolve previously applied layers so readily). Colophony is more rapidly soluble. And etc.

 

I *think* the rate of solubility is loosely correlated to the hardness / durability of the dried film, as well. 
 

I fear I may be a little careless in my terminology, using words like hardness and durability, but I hope the gist of my inquiry is clear.

 

This would be a fascinating - and time-consuming and expensive - experiment. I’m hoping someone has done the work already.

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Hi Folks... Not sure this is helpful, but found it interesting reading ... for a FP neophyte:).... A lot of other public domain books on the "Gutenberg Project"

https://www.gutenberg.org/files/17935/17935-h/17935-h.htm

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On 9/6/2019 at 2:23 PM, Julian Cossmann Cooke said:

Without the oil, the varnish turns to dust when two instruments knock against each other. 


 

Knock against each other?! Egads!  Are they fighting like elk?  Do their bridges get stuck together like antlers? 

I thought only banjos duelled.  And to think I came close to hanging an antique violin on the wall next to a teenaged guitar.  Who knows what indignities they might have visited upon my wife's piano.

Seriously, please clarify and verify your comment for the uninitiated. Thank you.

Sincerely,

Randy O'Malley

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On 2/9/2020 at 11:15 PM, Randall The Restorer said:

Knock against each other?! Egads!  Are they fighting like elk?  Do their bridges get stuck together like antlers? 

I thought only banjos duelled.  And to think I came close to hanging an antique violin on the wall next to a teenaged guitar.  Who knows what indignities they might have visited upon my wife's piano.

Seriously, please clarify and verify your comment for the uninitiated. Thank you.

Sincerely,

Randy O'Malley

The knocking happened because I hung two fiddles too close together and didn't stabilize one before walking back to the bench.  My bad in the first place.  What the fiddles themselves actually did to make them knock against each other I can't say.  But I haven't seen any fractionals crawling around the shop so I deduce that the fiddles were not bumsen-ing.  

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3 hours ago, Julian Cossmann Cooke said:

The knocking happened because I hung two fiddles too close together and didn't stabilize one before walking back to the bench.  My bad in the first place.  What the fiddles themselves actually did to make them knock against each other I can't say.  But I haven't seen any fractionals crawling around the shop so I deduce that the fiddles were not bumsen-ing.  

Thanks for responding, Julian.

If propagation in your instruments is a concern then don't use hide glue made from rabbit skins. 

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I am finding out how delicate this local resin spirit varnish is as I fit the bridge feet.  Just add these to the touch-up list.  But I suspect others who may work on the instrument down the road will curse my name.  The experimentation with the right mix of ingredients continues.

An object lesson in the fact that the odds of one's hitting the right combination on the first, second, or even third try are long indeed.  Not that I needed to find that out for myself.  A conversation with Joe Robson already had informed my thinking.  Still, it is human nature to think maybe, just maybe, our own experience would be one of those rare exceptions to the rule.  Good thing my ego is not as fragile as my varnish!

IMG_20200214_115148_853.jpg

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On 10/8/2019 at 11:53 PM, jezzupe said:

If one wants to increase the abrasion and chip resistance of shellac,a"hard shellac' can be made by adding some sodium hydroxide and or Drano crystals 

Crytsal Drano should be much more effective than pure sodium hydroxide (aka lye) available from a paint store. 

WARNING Don't get either solution on dried shellac unless you want to dissolve the film.  If it gets on skin it will turn your flesh to soap (saponification). Have vinegar handy for a neutralizer.

According to the National Institutes of Health's Household Products Database, the crystal form of Drano is composed of:

After Drano crystals are added to water, the reaction works as follows:

  1. Aluminium reacts with lye: 2NaOH + 2Al + 2H2O → 3H2 + 2NaAlO2, although the exact species in solution may be NaAl(OH)4.[1] The release of hydrogen gas stirs the mixture and improves the interaction between the lye and the materials clogging the drain. It's possible that pressure may build up inside the pipe, causing the hot, caustic solution to spurt out of the drain.
  2. Sodium nitrate reacts with hydrogen gas: Na+ + NO3- + 4H2 → NaOH + NH3 + 2H2O. This removes hydrogen, which poses a fire and explosion hazard and produces ammonia, which is also capable of decomposing organic material, albeit less aggressively than lye. The sodium hydroxide (lye) is consumed by further action of the first reaction.

Aluminum Oxide is one the hardest substances known to woman and man. It is used to polish and sharpen hardened steel.  Any particles in suspension might also act to brighten the shellac film (for this I defer to a Chemist).

Randy O'Malley, with help from wikipedia

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The last time I bought a can of drain cleaner I was able to find a brand that was just lye, but that was a while ago. In Drano the aluminum shards are visible, which is why I went brand shopping.

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OK, so I mixed up some 1704 for kicks, with 55 grams of seedlac, and 200 ml alcohol.  I added 2 grams of gum elemi, and let it dissolve for several weeks, mixing often.  Then heated to boiling and filtered.  Nice stuff!  There is one surprise, that the consistency has turned out like slightly thickened gravy, like corn-starch was used!  It gets runny when heated, but it's a bit goopy at room temp.  It is very brushable, but just not anything like the 'spirit varnishes' I've purchased before.  A completely different animal!  What's up, is this bad, good or indifferent?  Was there too much elemi?

In a way I like it, as it doesn't run, and allows a bit of rebrushing as it doesn't dry instantly.  The only down-side seems to be that it is a bit matte finish, and I have to be careful not to leave brush strokes.  Anyone with comments? I've used oil varnishes on recent instruments, so my experience is limited.

Thanks?

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I think this is quite typical of 1704, the culprit is the high wax content of the seedlac, I don't think the elemi that you put could be responsible, in the original recipe there is much more, 7.5 g per 45 g seedlac. In the original recipe there is also 9 ml of spike oil (Lavendula spica) which could improve the consistency a little, but I would not advise you to use it because in my experience it can give many problems of drying and hardening, perhaps only a few drops might help brushability. I haven't used the 1704 for many years (decades) anymore but used it in the early years. For the quantities that I have indicated, the original recipe includes 180 ml (143 g) of alcohol (Fiorini-Sacconi recipe found in the Weisshaar book)

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3 hours ago, Davide Sora said:

but I would not advise you to use it because in my experience it can give many problems of drying and hardening

Thanks Davide, my experience exactly.  I don't include spike lavender in any varnish anymore.  Others may have different experience...

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