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Andreas Preuss

Varnish application. - thick layers versus thin layers

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Did anyone here on MN ever make a test with varnish application? 

Here is what I am trying to find out: 

if we are using turpentine soluble varnish we can apply it in let's say 3 thick layers with a brush or in 100 ultra thin layers with a cloth. Is there any difference in the visual result?

Has anyone tried it?

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I use oil varnish (Joe's) thinned with spike oil to a rather thin brushing consistency, with some pigments,  3 coats over sealed wood will give

me the desired colour.

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Certainly the same varnish for the same given final thickness will look different depending on the number of coats that it was applied in.

My main consideration for a varnish is practicality of application. I have used fat long oil varnishes in the past but these take a long time to dry and even in my modern set up could get insect stuck to them. Now I use a lean oil varnish that becomes touch dry fast. I can apply 3 coats a day and up to 15 coats are needed for a strong red color. I find the leaner mix gives me the texture and fragility I seek.

At the Oxford Strad conference someone who knows more than me pointed out that Strad had cavalry stables across the street from his workshop. The proliferation of flies and dust must give an indication of what kind of varnish would be practical for him to use.

 

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Many thin coats of colored varnish give a very even colored finish, as the application variances average out in the end. A few coats of highly colored varnish makes it difficult to avoid splotchiness.

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13 hours ago, Melvin Goldsmith said:

Certainly the same varnish for the same given final thickness will look different depending on the number of coats that it was applied in.

My main consideration for a varnish is practicality of application. I have used fat long oil varnishes in the past but these take a long time to dry and even in my modern set up could get insect stuck to them. Now I use a lean oil varnish that becomes touch dry fast. I can apply 3 coats a day and up to 15 coats are needed for a strong red color. I find the leaner mix gives me the texture and fragility I seek.

At the Oxford Strad conference someone who knows more than me pointed out that Strad had cavalry stables across the street from his workshop. The proliferation of flies and dust must give an indication of what kind of varnish would be practical for him to use.

 

Interesting, Melvin.

When it comes to Strad Type of vartnish I only know from my restoration experience in NY, this stuff is really ultra thin. To imitate the AS stuff (basically regardless what Brandmair and other researchers have found) I try to get a deep intense yellow under the color varnish.Then I apply with a brush a color varnish of a brownish purple shade which will make (presumably by the principle of substractive color mixiing) a pretty intense orange red.

Recently, and this is the reason why I made this post, I was just thinking if at all it makes sense to apply the varnish even thinner, to the degree that you almost don't know that you applied something. I was actually more looking on the underlayer varnish (Bruce Tai calls it substratum). It seems that the same thickness of varnish applied in thinner layers gives more lustre to it.

 

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10 minutes ago, Bill Yacey said:

Many thin coats of colored varnish give a very even colored finish, as the application variances average out in the end. A few coats of highly colored varnish makes it difficult to avoid splotchiness.

Definitely.

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16 hours ago, christian bayon said:

In my experience, I notice more differences if the main amount of colour is near or far from the wood, not that much with the thick or fine layer.

Yes, this is my observation too. But it is also possible to use a different color varnish with darker hue when the varnish underneath is already yellow or orange. I have done that on a copy where I thought it looks too pale and it worked very well.

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" if we are using turpentine soluble varnish we can apply it in let's say 3 thick layers with a brush or in 100 ultra thin layers with a cloth. Is there any difference in the visual result? "

I don't even use thick coats when I'm building furniture! Thick coats are more prone to dripping, running, and other nasty things. Many thinner coats are the way to go. I use about 6 coats for either application.

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I have been moving toward thin highly pigmented layers. As Preuss mentions, subtractive color theory is very important to control the final result. IMO, the final layer in Golden Era Strads is very close to a magenta (color hue angle close to 0º.) However, this layer is usually badly worn thin leaving a red-side orange. The varnish layers rest on a golden yellow ground.

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On 4/24/2018 at 4:23 AM, Andreas Preuss said:

Did anyone here on MN ever make a test with varnish application? 

Here is what I am trying to find out: 

if we are using turpentine soluble varnish we can apply it in let's say 3 thick layers with a brush or in 100 ultra thin layers with a cloth. Is there any difference in the visual result?

Has anyone tried it?

I've tried all kinds of things, and there might be differences between the scenarios you have described, somewhat depending on whether each subsequent identical coating softens or dissolves the surface layer of the previous coating, sufficiently to blend them into something which acts as a single coating, or whether they remain as separate layers.

Melvin brought up some interesting notions about contamination.  A lot of junk from the local environment could have been incorporated into multiple slow-drying layers. I realize that this might not be exactly where Melvin was coming from, but I also think it's good to give some thought to the original intent of the makers, and how this could differ from what analysis today shows. Perhaps we could label Melvin's and my musings on this as "the horseshit theory",  just for fun? :)

Anyone who has owned a freshly-cleaned shiny black car has probably noticed how quickly it gets dirty.  Where I live, this happens fastest in the spring pollen season, and in the spring plowing season. (I'm downwind from some commercial crop-growing areas.)

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Friederich Meyer gave a speach in the 1995 Dartington Violin Conference in which he mentioned that there is quite a lot of dust in Cremonese varnish, that the varnish attracted lots of dust:

"By the way, there is always a lot of dust in old instrument varnishes, specially in oil varnishes and during analysis this can lead to wrong conclusions. Dust, containing many minerals, has a spectrum similar to earth colours or other minerals and therefore the analytical findings could possibly make us believe that the latter ones were deliberately incorporated in a varnish".

Imagine Cremona 300 years ago, with dirt roads, animals on the street and backyards - with their feathers and hairs, and the insects that were atracted by this animals, etc., it was far from being the "clean" city we know today.

I have some problems with small bees here, they get mesmerized by my varnish.

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I noticed the fiddle I'm varnishing now had a nice coating of pollen after sitting out most of the day in the spring sun. It's the reason I let the varnish skim over in the light box for a couples of hours before setting it outside to dry.. Once dry the pollen wipes off clean with a damp rag. I also go over it very lightly with 1500 wet dry paper to remove any nits before applying the next coat.

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Just some musings that may not be worth the time reading.  Reading this thread reminded me of how easily static electricity can build up.  The flash of thoughts that ran through my head was watching my son build a desk top computer with a static electricity ground strapped to his wrist to keep from ruining some sensitive parts, and how quickly and annoyingly static electricity builds in a petri-dish (sh%t! the meta pleural gland (little tiny ant part) just vanished).  Now varnishing an instrument via brush, rubbing, patting or combination there of.  Makes me wonder if there would be a benefit to grounding the instrument and how easily it could be accomplished.

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26 minutes ago, Jim Bress said:

Just some musings that may not be worth the time reading.  Reading this thread reminded me of how easily static electricity can build up.  The flash of thoughts that ran through my head was watching my son build a desk top computer with a static electricity ground strapped to his wrist to keep from ruining some sensitive parts, and how quickly and annoyingly static electricity builds in a petri-dish (sh%t! the meta pleural gland (little tiny ant part) just vanished).  Now varnishing an instrument via brush, rubbing, patting or combination there of.  Makes me wonder if there would be a benefit to grounding the instrument and how easily it could be accomplished.

LOL, reminds me of a former client of mine who was not only a fiddle freak, but also a major fireworks manufacturer. There were safety protocols in place, like always having grounding straps tied in, but I guess he couldn't 100% rely on every employee to follow all the procedures every time. Over the years, there were two major explosions in the manufacturing/assembly area, resulting in multiple deaths. http://edition.cnn.com/US/9812/11/fireworks/

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On 4/24/2018 at 5:26 AM, christian bayon said:

In my experience, I notice more differences if the main amount of colour is near or far from the wood, not that much with the thick or fine layer.

This effect is clearly seen in the wonderful photos you post. It almost appears as if the clear top coats in your varnish act like a optical magnifier, amplifying the ground colour below

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On 4/24/2018 at 6:28 AM, Melvin Goldsmith said:

At the Oxford Strad conference someone who knows more than me pointed out that Strad had cavalry stables across the street from his workshop. The proliferation of flies and dust must give an indication of what kind of varnish would be practical for him to use.

 

Wow. No wonder some people claimed that Stradivari used fast-drying spirit varnish.

However, remember that his house and workshop had an open area on the third floor for drying things. That may have helped a little.

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Where you got horses, you got flies. Lots of them. I can't think of a more inconvenient place for drying oil varnished violins.

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