Types of guitar finish (Full Version)

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rombsix -> Types of guitar finish (Apr. 27 2013 5:16:43)

Hey everyone,

Was just wondering if someone can provide us with a summary on the different types of finishes used on classical / flamenco guitars (for example, oil, French, urethane, nitro, lacquer, etc.) and their pros & cons.

Another question I have is about the term "high-gloss". Is that a specific type of finish, or is that an "extra option" that can be added to any type of finish?

For example, can you have a French polish "normal" finish versus a French polish "high-gloss" finish?

Thanks!

PS: Check this video out - it's cool. I love it when people "know what they are doing" and are "experts" who can come up with high-quality results.




FlamencoD -> RE: Types of guitar finish (Apr. 28 2013 2:26:06)

Good topic, I hope there are some replies.



rombsix -> RE: Types of guitar finish (Apr. 28 2013 3:05:11)

I hope so too...



krichards -> RE: Types of guitar finish (Apr. 28 2013 8:42:11)

There has been lots of discussion on previous threads about the pros and cons of various finishes.
Not sure I have the energy to do it again.

But, if someone starts us off, I'll no doubt get involved.



constructordeguitarras -> RE: Types of guitar finish (Apr. 28 2013 13:56:23)

High gloss refers to the final look and could be any type of finish. Any finish can be buffed to high gloss or not. Or a flatting agent can be added to a sprayed or brushed on finish to make it look matte (not so shiny).

I use shellac (French polish) because it is beautiful and safe to use.

Nitrocellulose lacquer is very fast to apply and cure but requires special equipment (such as a spray booth) and the wet material is hazardous to one's health (and explosively flammable). (I worked in a factory spraying finishes on furniture parts for three years.)

I love marine varnish as a finish but there are often problems with it curing on exotic woods (such as ebony fingerboard edges and rosewoods) and the solvent fumes have made me sick. But it is an extremely tough finish, not delicate like shellac or even nitro. (According to Romanillos, this is the sort of finish Torres used, not shellac.)



tele -> RE: Types of guitar finish (Apr. 28 2013 14:02:16)

How about poly? Thin layer of poly lacquer is very popular and conde hermanos for example use it



constructordeguitarras -> RE: Types of guitar finish (Apr. 28 2013 15:13:48)

I don't know what that is. There are many synthetic finishes which are polymers. I'm sure they all have their uses.



tele -> RE: Types of guitar finish (Apr. 28 2013 16:27:57)

Poly as polyurethane



rombsix -> RE: Types of guitar finish (Apr. 28 2013 17:31:29)

quote:

High gloss refers to the final look and could be any type of finish. Any finish can be buffed to high gloss or not. Or a flatting agent can be added to a sprayed or brushed on finish to make it look matte (not so shiny).


Thanks tio.



jshelton5040 -> RE: Types of guitar finish (Apr. 28 2013 18:06:44)

quote:

ORIGINAL: tele

Poly as polyurethane

I've never heard of polyurethane lacquer normally polyurethane is a synthetic varnish. Are you sure you're not thinking of polyester?



tele -> RE: Types of guitar finish (Apr. 28 2013 18:28:11)

Sorry I dont know much about finishes, just that polyurethane is used on some guitars, if its varnish or lacquer I dont know



tri7/5 -> RE: Types of guitar finish (Apr. 28 2013 18:56:58)

Poly is heavily used on electric guitars, not sure about flamenco guitars (at least not on the top, maybe the sides). It seems like it might deaden the tone as it's a pretty thick finish, almost plastic like when it dries.



C. Vega -> RE: Types of guitar finish (Apr. 28 2013 19:17:38)

Any finish can be applied thinly or too thick, including shellac. Note that I didn't say "French polish". French polishing is a technique for applying a finish (usually shellac), not the finish itself. Many makers who use shellac as a finish, whether its sprayed or brushed and leveled/rubbed/buffed out or applied in the traditional way with a pad and spirited off to a high gloss tend to say, often incorrectly, that their instruments are French polished.

The American guitar manufacturer Taylor uses a very thinly applied polyester finish that is cured by UV light. The ultra-high intensity UV tubes used to cure it are frightfully expensive (thousands of dollars each) and the finishers must dress in what essentially looks like a space suit when applying it. The finish cures in about 60 seconds.

Most Spanish factory guitars, including flamenco models and numerous instruments from high-end makers like Ramirez as well, are finished with a two-part catalyzed polyurethane that cures by chemical reaction.
Asian guitar factories have used polyester finishes for many years.

"Lacquer" has become a generic catch-all term for most guitar finishes other than shellac but when most professional wood finishers use the term "lacquer" they're referring to nitrocellulose lacquer which was once quite common but has fallen from favor in recent years. It is still used in the U.S. by manufacturers like Martin and Gibson but not on all of their instruments. A number of individual steel string makers in the U.S. also use it.

There are also oil finishes, varnishes, etc. based both on natural and synthetic ingredients too numerous to get into in a format like this.
There are many good books devoted to the subject. There's also a lot of bad information doled out by amateur "wood finishing experts" and others on the web.

Marine and other oil-based varnishes will cure just fine on ebony, rosewood and other exotics when applied over a good shellac washcoat.
Manuel Velazquez and Robert Ruck are two makers who have used and continue to use this type of finish.



krichards -> RE: Types of guitar finish (Apr. 29 2013 7:51:06)

French Polish (shellac) is without doubt a very beautiful and satisfying finish for the hand builder. Its safe to use, smells good, applied slowly and produces a depth of shine that is hard to beat. It also comes in natural yellow/orange shades, so generally, no artificial colours are needed.
The only problem is, its not very tough or durable. On the other hand it can easily be repaired.

Cellulose lacquer is a superb high gloss hard finish. But, its not safe for the hand builder unless expensive spray booths etc. are used.

Polyurethanes have a bad name because the factories tend to apply it too thick. But I use a product that is a mixture of Acrylics and Urethane. Its water based, easy to apply by brush and can be applied in a thin durable layer. I usually use a few sealer coats of shellac to get the colour I want, and then apply the Polyacrylic on top. It works very well and gives the best of both worlds.

Oils are used by some makers but I have no experience of these.

If I had to choose just one finish I'd choose to French Polish with shellac. Its just a very satisfying technique and gives a truly beautiful finish.



Anders Eliasson -> RE: Types of guitar finish (Apr. 29 2013 9:41:42)

Kevin, what is the brand of polyacrylic varnish and where do you buy it?

Also this with marine varnishes Ifind to be interesting. What kind of marine varnish do you refer to? There are so many types.



keith -> RE: Types of guitar finish (Apr. 29 2013 12:55:21)

rombsix--to respond to your question, and to follow up what charles vega stated, here is a good resource. do the "look inside" to see the topics covered by the author



http://www.amazon.com/Understanding-Wood-Finishing-American-Woodworker/dp/1565235487#_



Ricardo -> RE: Types of guitar finish (Apr. 29 2013 18:09:55)

Maybe Ramzi wanted a clear list. Like Techniques/type of stuff.

FRENCH POLISH (spongue/cloth build up)
shellac
oil based
Marine based
more?

SPRAY
nitrocellulose laquer
acrylic polymer
polyester
water based laquer
shellac????
more?

BRUSH ON
shellac?
paint? [:D]

TWO STEP CHEMICAL PROCESS:
catalyzed Polyurethane
Polyurea ??

Maybe folks can fill in the blanks above or add.
And mixed techniques like a shellac base first then spray later etc.

Here is a guy does shellac/french polish first then water based laquer/spray on top.

http://gicl.cs.drexel.edu/people/sevy/luthierie/guitarmaking_guide/finishing/finishing.html



jshelton5040 -> RE: Types of guitar finish (Apr. 29 2013 18:48:45)

quote:

ORIGINAL: Ricardo

FRENCH POLISH (spongue/cloth build up)
shellac
oil based
Marine based
more?

SPRAY
nitrocellulose laquer
acrylic polymer
polyester
water based laquer
shellac????
more?

BRUSH ON
shellac?
paint? [:D]

TWO STEP CHEMICAL PROCESS:
catalyzed Polyurethane
Polyurea ??


There are also padding lacquers (applied like FP), acrylic lacquers and catalyzed lacquers which contain urea so maybe that's what you're referring to with polyurea. Catalyzed lacquer can be used as a top coat (clear coat) since it becomes very hard and cures fast but it's sensitive to cold temperatures if multiple coats are applied so it's not a good substitute for nitrocellulose. Conversely acrylic lacquer is somewhat heat sensitive and can soften if the guitar is left in the sun or locked in a hot trunk.

I don't know why you put question marks after sprayed and brushed shellac since those are perfectly acceptable ways of applying it.

The poly prefix generally refers to polymer or polymeric. It has to do with the molecular structure and how the molecules link together as in "long molecule polymers" which are really outstanding finishes but not for guitars. Think of those clear coffee table tops with shells and stones embedded in them and you get the idea. Wasn't Ethan Deutsch involved in chemistry or chemical engineering in a previous life? If so he would be the one to ask about finishes.



rombsix -> RE: Types of guitar finish (Apr. 29 2013 21:55:29)

Thanks mates!



krichards -> RE: Types of guitar finish (Apr. 30 2013 7:34:42)

Anders
I use General Finishes Polyacrylic

You can buy it here
http://www.rutlands.co.uk/finishes-glues-&-materials/oils,-waxes,-stains-&-polishes/finishes---varnishes/GF10013/Polyacrylic

I use the gloss type



Ricardo -> RE: Types of guitar finish (May 1 2013 18:18:13)

quote:

I don't know why you put question marks after sprayed and brushed shellac since those are perfectly acceptable ways of applying it.


trying to organize for ramzi and wasn't sure since everybody only talked about shellac via FP. I thought why not apply with different technique? And also since you clarified that it is fine to brush it or spray it, how can one (meaning a layman player like me) tell the difference between applications if it is the same material? For example, Brune told me that Hauser (II) did not ever FP (or rarely did) and my father's guitar was almost certainly lacquered...and I was shocked.



jshelton5040 -> RE: Types of guitar finish (May 1 2013 20:43:27)

quote:

ORIGINAL: Ricardo
trying to organize for ramzi and wasn't sure since everybody only talked about shellac via FP. I thought why not apply with different technique? And also since you clarified that it is fine to brush it or spray it, how can one (meaning a layman player like me) tell the difference between applications if it is the same material? For example, Brune told me that Hauser (II) did not ever FP (or rarely did) and my father's guitar was almost certainly lacquered...and I was shocked.

The simple answer is "you can't". In my opinion it is visually impossible to tell the difference between a high gloss shellac finish (fp or not) and a high gloss lacquer finish. It's relatively easy to tell the difference between a properly applied thin lacquer or shellac finish and a thick factory finish. I know I'm considered a heretic for perferring lacquer over fp and I freely admit that I think fp shellac is a beautiful finish but so is lacquer. Soundwise I doubt there's any difference as long as the finish is thin.



Andy Culpepper -> RE: Types of guitar finish (May 1 2013 20:57:29)

I can almost always tell the difference between a FP and a sprayed lacquer finish. You look at the line where the heel meets the body, with a spray finish that line is usually "filled in" with finish more.

Both finishes are good if done well. FP can also be applied too thick and hurt the tone of the guitar same as lacquer IMO.



Anders Eliasson -> RE: Types of guitar finish (May 2 2013 7:23:47)

quote:

Anders
I use General Finishes Polyacrylic

You can buy it here
http://www.rutlands.co.uk/finishes-glues-&-materials/oils,-waxes,-stains-&-polishes/finishes---varnishes/GF10013/Polyacrylic

I use the gloss type


Thanks Kevin.
(its expensive)

What do you use for porefilling?



krichards -> RE: Types of guitar finish (May 2 2013 12:30:38)

Shellac and pumice and alcohol in the traditional way

I always use shellac as a base/sealer, so pumice is the logical choice.

If you try the Polyacrylic on dark woods you must be sure that it dries quickly to avoid a white bloom. I think this happens when the temp is low and/or the drying is slow.
Give it a trial on some spare rosewood before you use it on a guitar.



Anders Eliasson -> RE: Types of guitar finish (May 2 2013 13:45:34)

Ok, thanks.

Its just a maybe for the future idea. But I have saved the information.



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