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Rue

Instrument finishes...the missing link?

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Well - I've been reading about violin varnishing for years...:P

Now I'm just looking at guitar finishes...sorted out nitro (many layers, subject to yellowing, aging), urethane (only 2 coats used, not as yellowing, tougher), and polyester (thick, tough, weather resistant and can be colourful).  I'm mostly interested in the urethane finish used on classical guitars - not so much what is used on electric guitars.  I understand some classical guitars are also finished more like violins.  

I'm still missing something.  <_<

-Why are some violin makers fussing with 30 coats of varnish, while others are happy with 2 or 3? 

-Doesn't 30 thin coats of varnish on a violin equate to one thick coat of varnish?

-Why are classical guitar makers happy with 2 coats of urethane?  Why aren't they using violin varnishing techniques?  To save time?  The difference between factory and small-shop management?

-Is it just the size difference of the instrument?  Are violins that much fussier?  I see urethane coats on mandolins.  Is it the difference between a bowed and plucked instrument?  What about cellos and double basses?  Can they function well with a urethane finish?

-And finally, why - when I deliberately bought a high gloss urethane to finish my pine plank plant bench (because I actually wanted a thick, shiny finish on it) and even after 3 coats, it still looks like I only applied a very thin coat of a matte finish varnish?

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I imagine that violin makers haven't moved on just for the sake of sticking to tradition. Surely there can be better alternatives that are readily rejected out of tenacity to the traditions of the craft. Maybe there aren't viable alternatives. Who knows. 

Why can't I just put a coat of Arm-R-Seal on a violin and be happy?

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Some of the finish choices are directly tied to.... production cost/retail price.

At the highest levels most classical makers will still use the more traditional "Shellac "French Polishing" system that was most common in most guitars classical/steel string until the introduction of nitrocellulose lacquers in the late teens and twenty's of the last century.

Varnishes were not uncommon and many makers used some combination of varnish/shellac...[ I use varnish on back and sides and FP the tops of the ones I build.

Nitro was the common finish up to the latter part of the 20th...., primarily in steel stringed guitars, being able to spray and the fast drying qualities were perfect for production and Nitro was protective enough and is a good finish in terms of damping issues. Used by Martin, Gibson, etc all the top makers and still used today in the standard to upper price range.

The newer finishes..... poly and urethane are even easier in production application, quite durable, and usually seen on lower priced production instruments. Also there is significant evidence that they are less desirable acoustically.

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39 minutes ago, Rue said:

Well - I've been reading about violin varnishing for years...:P

Now I'm just looking at guitar finishes...sorted out nitro (many layers, subject to yellowing, aging), urethane (only 2 coats used, not as yellowing, tougher), and polyester (thick, tough, weather resistant and can be colourful).  I'm mostly interested in the urethane finish used on classical guitars - not so much what is used on electric guitars.  I understand some classical guitars are also finished more like violins.  

I'm still missing something.  <_<

-Why are some violin makers fussing with 30 coats of varnish, while others are happy with 2 or 3? 

-Doesn't 30 thin coats of varnish on a violin equate to one thick coat of varnish?

-Why are classical guitar makers happy with 2 coats of urethane?  Why aren't they using violin varnishing techniques?  To save time?  The difference between factory and small-shop management?

-Is it just the size difference of the instrument?  Are violins that much fussier?  I see urethane coats on mandolins.  Is it the difference between a bowed and plucked instrument?  What about cellos and double basses?  Can they function well with a urethane finish?

-And finally, why - when I deliberately bought a high gloss urethane to finish my pine plank plant bench (because I actually wanted a thick, shiny finish on it) and even after 3 coats, it still looks like I only applied a very thin coat of a matte finish varnish?

Hi Rue,

I made an electric guitar with my son some time ago.

When I said that it's going to be varnished with violin varnish he was skeptic, but not after.

https://goo.gl/photos/n2DbJj4Z47GXCkwB7

(3-4 layers of violin varnish)

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The professional guitar makers I’ve met are still French polishing their guitars with shellac. A lot of people use lacquer as a time saver, but that definitely has consequences.

 Believe me, there are violin makers out there that have used polyurethane and other lacquers on their instruments. The results have not been good aesthetically or acoustically. A lot of cheap rental instruments are varnished with a spray lacquer because it’s fast and can withstand abuse fairly well. Unfortunately this finish tends to be detrimental to sound; that’s a large part of the reason why an instrument made poorly but varnished decently can often sound much better than one made well but varnished poorly.

If you’re making electric instruments and a reverberating body isn’t important, using lacquers is less of a concern. 

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19 minutes ago, The Violin Beautiful said:

The professional guitar makers I’ve met are still French polishing their guitars with shellac. A lot of people use lacquer as a time saver, but that definitely has consequences.

 Believe me, there are violin makers out there that have used polyurethane and other lacquers on their instruments. The results have not been good aesthetically or acoustically. A lot of cheap rental instruments are varnished with a spray lacquer because it’s fast and can withstand abuse fairly well. Unfortunately this finish tends to be detrimental to sound; that’s a large part of the reason why an instrument made poorly but varnished decently can often sound much better than one made well but varnished poorly.

If you’re making electric instruments and a reverberating body isn’t important, using lacquers is less of a concern. 

What he said. There's wisdom in those observations!

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This is the kind of finish for your table ,

https://www.amazon.com/1-Gallon-Leveling-Perfect-Counter-Tabletops/dp/B079CR71SL/ref=sr_1_2_sspa?ie=UTF8&amp;qid=1546978055&amp;sr=8-2-spons&amp;keywords=epoxy+resin+crystal+clear&amp;psc=1

 

If you took some cooked down pine resin cut with some acetone and colored it first, but not enough to burn it,,, it would really show it off, then apply the epoxy it would be the real deal. The finishes used for the high gloss applications have been specifically formulated  with extra high solids content so it won't grow to the substrate and go flat as at dries. Industries that use this stuff for a living don't have time to go back and keep adding coats till it stays shiny. Generally not sold in your local outlets, professional use only.

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I used only shellac on my guitars as many other guitar makers since it can be done in a quite dusty workshop  without a uv chamber. PU varnish can sound good if applied thin but won't likely survive 300 years without getting ugly. Since guitars usually "die" after 40-80 years, that's not a big issue...

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2 hours ago, Rue said:

Well - I've been reading about violin varnishing for years...:P

Now I'm just looking at guitar finishes...sorted out nitro (many layers, subject to yellowing, aging), urethane (only 2 coats used, not as yellowing, tougher), and polyester (thick, tough, weather resistant and can be colourful).  I'm mostly interested in the urethane finish used on classical guitars - not so much what is used on electric guitars.  I understand some classical guitars are also finished more like violins.  

I'm still missing something.  <_<

-Why are some violin makers fussing with 30 coats of varnish, while others are happy with 2 or 3? 

-Doesn't 30 thin coats of varnish on a violin equate to one thick coat of varnish?

-Why are classical guitar makers happy with 2 coats of urethane?  Why aren't they using violin varnishing techniques?  To save time?  The difference between factory and small-shop management?

-Is it just the size difference of the instrument?  Are violins that much fussier?  I see urethane coats on mandolins.  Is it the difference between a bowed and plucked instrument?  What about cellos and double basses?  Can they function well with a urethane finish?

-And finally, why - when I deliberately bought a high gloss urethane to finish my pine plank plant bench (because I actually wanted a thick, shiny finish on it) and even after 3 coats, it still looks like I only applied a very thin coat of a matte finish varnish?

[Moves upwind and well away from her outdoor varnishing area, and, after stepping under a Clorox shower, opens the visor on her suit helmet.]

Have you considered using urushi

[Reseals, does a pressure check, and goes back to feeding various local Toxicodendron species through a cane juicer.] ;)

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There are some other pluses with French Polish/Shellac.

I use Everclear to dissolve my flaked shellac.

Shellac = bug poop..... basically non toxic

Everclear = non toxic, unless you're using it in your Bloody Mary's ...... and then only if you drink too many Bloody Mary .

Oil: used in minute quantities during application, typically; olive, walnut, mineral.... again non toxic

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Coatings used on wooden objects vary almost infinitely.

Basically you have some sort of solid combined with some sort of liquid to allow it to be spread on the wood. This can include resins and gums both natural and synthetic as well as mineral powders. The choice of resins and solvents or oils depend totally on what kind of film is wanted, ease and labor costs of application, and desired protective properties.

When used on instruments the acoustic effects must also be taken into account.' Guitars and violins are different in that instruments which receive a single impulse of energy to start their vibration benefit from less damping while instruments which have a continuous input of energy from a bow benefit by having coatings which add damping to some degree.

There are lacquers and spirit varnishes which can be formulated and applied to achieve either goal where as drying oils generally add some damping. There are way too many generalities made about spirit vs. oil  especially since many fine finishers use layers of several different coatings in building up the final film.

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3 minutes ago, nathan slobodkin said:

Coatings used on wooden objects vary almost infinitely.

Basically you have some sort of solid combined with some sort of liquid to allow it to be spread on the wood. This can include resins and gums both natural and synthetic as well as mineral powders. The choice of resins and solvents or oils depend totally on what kind of film is wanted, ease and labor costs of application, and desired protective properties.

When used on instruments the acoustic effects must also be taken into account.' Guitars and violins are different in that instruments which receive a single impulse of energy to start their vibration benefit from less damping while instruments which have a continuous input of energy from a bow benefit by having coatings which add damping to some degree.

There are lacquers and spirit varnishes which can be formulated and applied to achieve either goal where as varnishes generally add some damping. There are way too many generalities made about spirit vs. oil  especially since many fine finishers use layers of several different coatings in building up the final film.

Agree totally. My responses to Rue's OP where directed entirely towards Guitar finishing. The damping issue is the crux of the differences between what is desirable on a guitar vs violin.

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1 hour ago, Michael Jennings said:

Agree totally. My responses to Rue's OP where directed entirely towards Guitar finishing. The damping issue is the crux of the differences between what is desirable on a guitar vs violin.

All humor aside, I'm still trying to figure out where urushiol-based lacquers might fit into violin varnishing.  The Chinese have used quite a bit of it, and the one I have with cashew varnish has very good sound, as well as looks lovely.  As far as how well it holds up to the test of time, I feel that antique Japanese lacquerware has more than answered that question.  OTOH, the uncured varnish is severely toxic, it's expensive as well as hard to obtain, and the issues involved in rolling your own by concentrating and separating fluids from American poison ivy and its relatives preclude anyone outside an insecticide or CW lab from taking a crack at it.  I would like to see someone try making it commercially, as I believe there would be a market for it.  :)

BTW, when clearing such plants out of your yard, don't ever throw the stuff in a fire, just pile it up by itself someplace, and let it rot.  :wacko:

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Two things to consider. 

1. It is more difficult to achieve an even colored varnish with few thick coats than with many thin coats. 

2. Fewer thick coats are less transparent than more thinner coats. I can tell by experience. When still at school some of my class mates experimented with thickening the school formula spirit varnish while I went the opposite direction and diluted the varnish to the maximum. My varnish was much more transparent in the end.  

 

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Vdm, From the few pieces of Japanese/Chinese lacquerware I've seen in person I have to admit its beauty.

I am neither a scientist nor an engineer [ Never played either one on TV].... although I'm intrigued by many of the ideas I read on these pages, I freely admit that they are way beyond my skill or knowledge set.

I can at least sharpen a gouge and make my self a sandwich,...so there is that.:wacko:

No poison ivy that I'm aware of on my island ..... but I will certainly take you advice to heart

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14 minutes ago, Andreas Preuss said:

1. It is more difficult to achieve an even colored varnish with few thick coats than with many thin coats. 

Perhaps you are right. However there are those who have figured out a way to do it one or two thick coats. Ground coat and single coat of oil varnish. Courtesy of Roger Hargrave.

54.thumb.JPG.32f5b7dc4daa3c94341450246a76589a.JPG

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There are a variety of differences among various varnishes and the selection depends on how fussy you are willing to be in application along with the color, finish and wear you want from the surface.

Highest quality violin varnishes are noted for their transparency and classic color palette (oranges, reds, golds, browns). With NC, PU and PE, it can be a big challenge to get a highly transparent color, especially in the color shades considered most desirable for violins.

Polyurethane can frequently have a somewhat low refractive index. This means that although the film itself can be very clear, it will not preserve fine details of wood grain without  first applying some leveling ground with an RI closer to the wood RI. It would also tend to desaturate the underlying colors of the wood. I've seen some amazing stuff with water-based PU and compatible dyes that also have a wood-compatible RI: crystal clear, rich color, highly yellow and UV resistant and very durable. But nothing that would be considered a classic color shade for a violin.

Polyesters tend to have a higher RI than wood. So you still want to preprocess the wood with a suitable ground. But the higher RI of a clear PE finish can really make the underlying colors seem more brilliant. I do not know anything about the ability to color PE to give it a transparent color. While it might be worth considering as a clear finish for a violin, challenges to applying the varnish might be a deal breaker. Also, does one really need such a high wear resistant finish to the violin body?

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7 hours ago, Urban Luthier said:

Perhaps you are right. However there are those who have figured out a way to do it one or two thick coats. Ground coat and single coat of oil varnish. Courtesy of Roger Hargrave.

54.thumb.JPG.32f5b7dc4daa3c94341450246a76589a.JPG

Well, that's a complete different technique. The formula developed by Hargrave and Koen Padding works without volatile solvant, so it is not a varnish in the modern sense.

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2 hours ago, Andreas Preuss said:

Well, that's a complete different technique. The formula developed by Hargrave and Koen Padding works without volatile solvant, so it is not a varnish in the modern sense.

I think  Roger's  varnish is a very simple oil varnish. I'm not sure  that he or Koen would claim to have developed  it, other than tweaking  the  details to their  own  liking.

When I was in school, we had the good fortune  to  have the chemist  from  the  local paint factory  teach us. He brought  us on a tour of the plant. In the main factory was a kettle two stories  high, in which they cooked huge batches for making oil paint. The process was very much the same but huge! And they used synthetic  resins. 

Outside in the yard were six or eight smaller kettles, each  set into a pit fitted with gas jets, and covered with a tent. They used these for small 1000L batches, for varnish. The process  was  exactly the same as ours, and they made varnish to order, including copal varnish for example, and yacht varnish.  The varnishes  were thinned just to make them brushable.

For years I varnished in one heavy  coat, but now I use three. Oil varnish  is very easy to spread, with a long open time. But one heavy coat will tend to dry on the surface and remain soft underneath  for a long time, and you must get the balance  right  or it will slump or run or craze or wrinkle. I've found three coats better. I use no solvent other than a little that I add  to the pigment to help me mix it in.

Several coats  allow  you to  put more colour close to the wood and then make slight adjustments  in the upper  coats. And if you apply each coat as soon as the last is just set enough  to paint over, the varnish will become  a homogenous  layer. 

For me, spirit  varnish  is so much more difficult  to use, as the solvent always wants to dissolve  the  previous  coat, and the whole thing goes to pot, so I gave up on it altogether years ago.

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38 minutes ago, Conor Russell said:

For years I varnished in one heavy  coat, but now I use three. Oil varnish  is very easy to spread, with a long open time. But one heavy coat will tend to dry on the surface and remain soft underneath  for a long time, and you must get the balance  right  or it will slump or run or craze or wrinkle. I've found three coats better. I use no solvent other than a little that I add  to the pigment to help me mix it in.

Several coats  allow  you to  put more colour close to the wood and then make slight adjustments  in the upper  coats. And if you apply each coat as soon as the last is just set enough  to paint over, the varnish will become  a homogenous  layer. 

thanks for summarizing your workflow Conor this is very helpful... do you use a brush or apply with your fingers?

Instead of a volatile solvent-based oil varnish, i'm now learning how to use a solvent free oil varnish (made by Eugene Holtier). It is very similar to what Roger used in the bass book. However I'm unable to apply it in a single coat like what's illustrated in the bass book, as the varnish will run and wrinkle as you note above.

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I'm making mandolins and in our world all kinds of varnishes or lacquers have been used and tested. I personally have used my own cooked varnish, Tru-oil, Hidersine oil violin varnish, and few brands of canned oil varnishes (alkyd or phtalic...) I also worked with polyurethane on gunstocks a,d generally do french polish the top coats. General consensus (in mandolin makers community) is that unless you use excessively thick finish the sound is not really affected. Of course with sprayed and then sanded lacquers getting the thin finish is harder than with brushed or french polished varnishes.

Appearance of all finishes is so close that I cannot tell now which instrument I finished with which varnish inless I find a finishing  photo with the bottle/can in background...

Durability can be different but often the player is the main factor - I once finished two instruments together and one came back for adjustment after 6 monts with badly weathered finish while the other was still like new. The first player had extremely aggressive sweat - his sweat ate the whole french polished layer and transformed it into sticky rubbery mass in the areas of direct contact. SO I just cleaned it off and left the oil varnish without FP. Some of the modern varnishes will be more prone to flaking off in larger piece rather than chipping off like some old varnishes but thay can be also adjusted by adding various resins.

There are so many rumors about finishes floating around that it is hard to keep open mind and evaluate each finish type based upon real results and not just hearsay.

Top tier violin makers are of course very limited by tradition and expected appearance and aging that can be achieved mostly by using the typical oil varnishes. And of course all the mystque that is added to the process of cooking and finishing can add value to many customers. You gotta do what paying customer wants....

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56 minutes ago, HoGo said:

...

There are so many rumors about finishes floating around that it is hard to keep open mind and evaluate each finish type based upon real results and not just hearsay.

...

And that's my problem...

15 hours ago, Violadamore said:

...

BTW, when clearing such plants out of your yard, don't ever throw the stuff in a fire, just pile it up by itself someplace, and let it rot.  :wacko:

I remember, a kazillion years ago...someone becoming very very sick because they had breathed in the smoke from a brush pile containing poison ivy...

18 hours ago, Peter K-G said:

Hi Rue,

I made an electric guitar with my son some time ago.

When I said that it's going to be varnished with violin varnish he was skeptic, but not after.

https://goo.gl/photos/n2DbJj4Z47GXCkwB7

(3-4 layers of violin varnish)

Lovely!  Which is why I wondering why the go-to with guitars isn't a violin-type varnish.  Personally, I would prefer that to the glossy urethane finish - but was wondering if the reason it's the go-to is because of different durability factors.  Now, I can see that on an electric guitar, but not necessarily on a classical guitar.  And I know it exists - but I can't afford buying a $6000  custom guitar to find out what it's actually like...

However, if I ever win The Lottery....

18 hours ago, Evan Smith said:

This is the kind of finish for your table ,

https://www.amazon.com/1-Gallon-Leveling-Perfect-Counter-Tabletops/dp/B079CR71SL/ref=sr_1_2_sspa?ie=UTF8&amp;qid=1546978055&amp;sr=8-2-spons&amp;keywords=epoxy+resin+crystal+clear&amp;psc=1

 

If you took some cooked down pine resin cut with some acetone and colored it first, but not enough to burn it,,, it would really show it off, then apply the epoxy it would be the real deal. The finishes used for the high gloss applications have been specifically formulated  with extra high solids content so it won't grow to the substrate and go flat as at dries. Industries that use this stuff for a living don't have time to go back and keep adding coats till it stays shiny. Generally not sold in your local outlets, professional use only.

I think that's actually much thicker and glossier than I wanted.  But the finish I ended up with (while perfectly inoffensive) just wasn't the finish I was expecting.

17 hours ago, Violadamore said:

...

Have you considered using urushi

...

I can answer - with perfect honesty - no. ^_^

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On ‎1‎/‎8‎/‎2019 at 3:10 PM, Violadamore said:

BTW, when clearing such plants out of your yard, don't ever throw the stuff in a fire, just pile it up by itself someplace, and let it rot.  :wacko:

Very true...stay upwind. As young boy of 7 our family rented a beautiful house of stone on an old dairy farm. The land was sold and developed into a sub division. The place was covered in poison ivy and I remember them burning large piles of it.  I remember standing in shorts,..no tee shirt and watching the piles burn and smoke and the next day the itching started. I remember my mom putting calamine lotion on almost my whole body.

 

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