Electrostatic varnish (Full Version)

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rojarosguitar -> Electrostatic varnish (Jan. 19 2018 6:09:03)

Im curious about the technology behind the electrostatic coating of guitars. I have a flamenca blanca from Mundo Flamenco that has been made in China and distributed by a spanish distributor. It has a very nice, homogenous, hard and thin varnish that looks good and seems to have only little damping (compared to the thick varnishes one sees often on cheaper guitars). It also seems to be extremely durable and resistant to scratches.

I have been told that this varnish is sprayed in chambers and attracted to the guitar via electrostatic charge. By the regulating of the voltage the thickness of the layer can be controlled very finely. Afterwards the lacquer is hardened in a UV booth.

I wonder whether this is true or just a fantasy story?

And if it's true, I'd like to know how this technology is exactly called, so that I can gather some information about it. What kind of lacquer is it that they use for this kind of coating? Is it water based?



RobJe -> RE: Electrostatic varnish (Jan. 19 2018 10:29:52)

Here is the equipment.

Sad that powder coating has to be baked - the ashes of your new guitar delivered in a small urn! But electrostatic painting seems to offer the opportunity of blue sunburst. No idea about the acoustic properties.

https://www.alibaba.com/product-detail/Anti-electrostatic-UV-Acoustic-guitar-including_786843368.html

Rob



estebanana -> RE: Electrostatic varnish (Jan. 19 2018 11:41:34)

Rob, if you want a powder coating finish, you must specify you want the aluminum negra not the rosewood negra.



Morante -> RE: Electrostatic varnish (Jan. 19 2018 15:24:06)

I have a guitar finished by this technology and it looks great and sounds great.

However, it is a steel bodied dobro, so I would not even like to think what this technology would do to my Gerundino[;)]



RobJe -> RE: Electrostatic varnish (Jan. 19 2018 20:29:17)

quote:

you must specify you want the aluminum negra not the rosewood negra


Glad you are using the proper terminology. Blancas are made from cypress - any other material, whatever the colour is a negra.

UV cured painting looks interesting in one respect - that is being able to accurately contol the thickness. But from the machinery seen you might need to send 100 guitars at a time for finishing to make it cost effective.


Rob



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constructordeguitarras -> RE: Electrostatic varnish (Jan. 20 2018 3:30:34)



https://www.taylorguitars.com/guitars/acoustic/features/finish
"Gloss Finish
"Other than varnished guitars (Baby, GS Mini, Academy Series, 100 Series), all of our guitars are sprayed with UV-cured polyester — at least to form the base coat over the paste-filled surface. On full-gloss models, the base coat is sanded level then sprayed again with the same material, which is finally rubbed out and robotically buffed to gloss. While our standard gloss finish has an average thickness of 6 mils (6 thousandths of an inch), several Taylor series feature an ultra-thin 3.5-mil gloss finish. (This includes the 600, 800, 800 Deluxe, and 900 Series). The thinner coverage reduces the damping effect on the woods, resulting in a livelier, more resonant sound."



estebanana -> RE: Electrostatic varnish (Jan. 20 2018 3:49:19)

Ever try to do touch up and repair work on Taylor finish? You can't, you have to have the same **** sprayed on it with proprietary system.

Shellac and lacquer forever forward in independent shops. It's a non starter this cured poly, it's great for large scale factory work, but it's not as good as an A grade French polish or nitro finish. The factory guitars are fine too, but from the standpoint of carbon footprint, environment, waste, solvents, equipment, cleaning, all that shellac is better for the planet.



jalalkun -> RE: Electrostatic varnish (Jan. 20 2018 15:15:17)

What about mixing resins into shellac, like copal or sandarac? Do any of you see an advantage in this stuff?



constructordeguitarras -> RE: Electrostatic varnish (Jan. 21 2018 3:43:14)

quote:

What about mixing resins into shellac, like copal or sandarac? Do any of you see an advantage in this stuff?


I've thought about that too, every time I read about violin varnishes. I think they make the finish softer, so less suitable for guitars rather than more. But I haven't tried them.

Hey, Stephen, what do you put on cellos?



estebanana -> RE: Electrostatic varnish (Jan. 21 2018 4:12:06)

I use a pine resin/cooked oil varnish, applied with fingers.

Adding copal and sandrac, elemy, benzoin etc. to shellac is not a great idea. Shellac is complete by itself and the alterations often result in crazing or soft finishes later. Layering 'lean over fat' by accident can result in disasters.

Sandrac is hard. Think about different thicknesses in microns of shellac, some areas, due to uneven human application, low spots on the surface of the wood etc. the shellac film will be uneven if measured out in microns. Adding a hardener to shellac will create areas that are thicker and harder than areas adjacent to areas where the film is thinner. You're setting up places that have less ability to move next to areas that can move if the wood moves. If the guitar gets cold for example and moves a lot, the sections of finish will move at different rates. The result is crazing, craquelure. It's not a good idea to adulterate the shellac.

Adding gums a resins to shellac in guitars, which are in contact with the body makes the finish susceptible to damage is body chemistry effects the resins in the shellac. Acidity of perspiration can harm resins.

Elemy is a soft gum, put that in there and the shellac will be compromised in hardness. Copal is hard, similar to sandrac....why mess up good shellac?

There is a such thing as spirit varnish, which is shellac, seed lac usually, mixed with gums and resins and then heated a brushed on, but it creates a malleable self healing finish that is for violins, which require a different quality and softer varnish for them to sound best. Hard regular shellac films for guitars, softer varnishes for violins. It's part of the way the instrument functions that calls for the different qualities in varnish.



rojarosguitar -> RE: Electrostatic varnish (Jan. 21 2018 10:21:12)

Thanks for the responses (including the humorous ones). I'm not going to buy a production line from Alibaba (LOL), was just curiousabout what I had heard abot that Mundo Flamenco guitar. The coating seems to be very good, hard and thin, with little damping.



constructordeguitarras -> RE: Electrostatic varnish (Jan. 21 2018 13:33:07)

Great explanation, Stephen.



jalalkun -> RE: Electrostatic varnish (Jan. 22 2018 7:46:47)

It does make sense and you explained it very well. but two questions:

1. Why is a softer, more malleable finish sub-optimal for guitars and
2. would these differences of hardness on a µm-level still be there if the components are cooked to a homogenous varnish and applied thinly and evenly?



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