Official Luthiers Forum!

This is a separate thread that is addressing some of the points that came up in Ed's Clean Armor thread.
Don, you mentioned that you are exploring a finish that will allow a guitar to look good without special care, and what could probably be called abuse in your bug spray analogy. And you drew an analogy to a Fabergé eggs referring to guitars that are so fragile they stay in the case.
I can see where you are coming from and wish you luck in your quest. Personally, I'd never go near that stuff. There are some hefty hazard ratings regardless if the products are 100% solids. But, obviously this is a risk you are willing to take.
All the finest guitar players I have come into contact with and some for whom I have built guitars realize that a guitar that is played will show signs of wear and tear. They expect a guitar to hold together and be stable but nicks and dings are not even a minor concern provided the guitar is giving them what they want. If we look at the Fabergé egg analogy again it would seem the guitar that retains a super glossy, non-dented finish is more like the egg than the one that is well played and has the scars to prove it.
This next bit is not addressed solely to Don. Have any of you had the chance to inspect guitars from the pre-nitro days? For production shops look at Lyon & Healey who were pushing out vast numbers of guitars under different brand names. Take a look at early Martins. I've never had my hands on an Orville Gibson instrument but most seem to have their original finish. Then, look at antique Spanish guitars and Hauser I guitars. I inspected an Enriqué Garcia from 1910-1920 that had been played lots and it looked remarkably good. I had the good fortune to inspect 2 Torres guitars that, again, had been played lots and still had the original finish. I could go on but you no doubt get the drift.
None of these guitars looked the way they did when they left the builder's shop. They all had honest wear which had no impact on the value. A player would place a value on how it plays and sounds and a collector would place a value on it by how rare it is.
Most of these guitars had some sort of shellac finish (possibly with added gums). Folks more knowledgeable than I have said Torres' finish is some sort of a copal oil varnish.
I think it is well established that a thin finish of .003" or less does not prevent dents and dings to the soundboard no matter what the finish is. I often see builders say "it doesn't matter what the finish is so long as it is thin". In logical terms this is a claim. But no evidence is supplied to back it up. I used to spray nitro on the soundboards of my classicals and just use steel wool to finish it, like John Gilbert used to do. The thickness was close to or less than .003" I shipped one of these guitars out to a dealer and it hung around for probably about a year without selling. In the mean time I had switched to French polished shellac. I had the guitar shipped back to me and there was a certain vitality missing from this older guitar when compared with my French polished guitars. It was easy to strip with lacquer thinner and then re-polish with shellac. The difference was clearly audible. I'm sure some are thinking confirmation bias. I cannot prove them wrong but at least I had a control by listening to the same guitar with 2 different finishes.
I have mentioned this before on this forum but I think the answer to an appropriate finish for us hand builders is staring us in the face: shellac. Lots of information was lost when the world switched to synthetics for wood finishes. But much info has been rediscovered in the past 25 years as people have become interested in shellac again. Whether you believe lac resin was created by God or the result of evolutionary biology its sole purpose is to stick to wood. i.e. tree branches.
I look to the earlier guitars I mentioned in this post as proof that a low tech, non-toxic finish can indeed hold up very well for over 100 years, and not hinder the sound, which is what we are all seeking.

_________________
Stay with the happy people.
--Reynolds Large

This is why I’m also interested in the Royal Lac. Can be applied in French Polish but cures to the hardness of polyester, immune to alcohol and sweat. Aside from the work it takes to FP, it seems ideal…

A buddy of mine back in Missouri tried RL on his hammered dulcimers and it was an abject failure that cost him $. I couldn't get RL to work for me either and I tried a few different methods. I've written about my travails which will show up in a search.
Maybe RL will be the ticket for you. If you get some nice results please post details.

_________________
Stay with the happy people.
--Reynolds Large

I have a friend who can consistently get a 1.5mil finished result. I do know that people had problems at one point but at this time it seems to be resolved…

I just got home from working all night as I do and have been doing for over a year now we are so busy.

Finish can be heard, sadly and too much of the wrong finish can result in a terrible sounding instrument.

The best sounding guitar that I ever built is French polished shellac and was intended to be an adult owned and cared for instrument. It also weighs 2.9 lbs.... It's my go-to geetar to this day.

Many of the instruments that I work on that are made in China and these can be high end stuff too that cost several thousand dollars often have thick finish and they sound "clicky" to me which is not desirable. I no longer hear the tone wood but I hear the dang finish when it's too thick. It's even more noticeable on mandolins IME.

Back in the day when I was building and I had to reconcile the need for a tough finish for a gigging musician with the need for a great sounding guitar what my circle of friends arrived at was Polyester for the back and sides, cat poly Ala Mr. Joe White and a French polished shellac top.

But I totally agree finish makes a huge tonal difference as to what finish it is, how thick it is, how restrictive it is, etc. etc. etc. I likely handle and play more instruments than most here with thousands under my belt repaired now and the difference that finish can make for better or worse is absolutely obvious to me it's real and can be a game changer.

I know EXACTLY what you mean by 'clicky.' Great way to describe it.

---

I don't know exactly when I started doing FP but a good 7 or 8 years now probably and I noticed a difference immediately in tone. And I didn't start doing FP because I thought it would be better for tone, I started doing it because it is a safe small shop finish with thousands of years of history to back it up and with a few hundred years in the musical instrument world. So I think that rules out at least some confirmation bias.

I have used RL on a few now and have gotten really good results. My phone camera and me basically suck at taking pics but here are a few of this one done in RL. I use the FP technique for applying RL with oil and all.

I still love the idea of the perfect finish and look forward to Ed's results with the ClearArmor stuff. I'd love nothing more then to have a guitar totally finished in 3 days. I'm even willing to give up a bit of pure tone for it but not much.

I'm pretty big tent when it comes to finishes. By that I mean: Different folks have different needs and priorities, and different finishes can work for different people.

I French polished all of my early guitars. They sound really good, but they don't wear well. And that's OK for those guitars.

Right now, I'm trying to put a more durable finish on, and still have them remain great sounding guitars. I am in the camp of believing that the thickness of the material matters a lot more than the type of material used when it comes to the impact on the tone of the guitar.

I know there are builders who make great sounding guitars and finish them with more durable materials, and they remain great sounding guitars. James Olson and Kevin Ryan use UV cured finishes. There are lots of builders using catalyzed finishes. UV cured finishes and catalyzed finishes are not very different from each other once they are solid on the guitar. So, I just don't agree with the notion that using a modern finish will doom the tone of a guitar. These builders prove otherwise. When applied thin, the durable finishes can still yield a great sounding guitar.

Tom referenced the notion of finish enhancing the tone of the guitar. I don't really see things that way. I think thick finishes (of whatever material) hamper the tone of the guitar, and thin finishes (of whatever material) hamper the tone less. I don't see any finishes making guitars sound better. That's something violin family builders subscribe to, but I think it is rare among guitar builders to think that a finish makes a raw wood guitar sound better.

Regarding risk to the builder: I think it is appropriate for anyone spraying any finish to take better precautions than many currently do to protect themselves. This is true no matter what the finish material is. Think about it: There is this liquid that will turn into a solid (after evaporation of solvent, or a chemical reaction occurs), and we are atomizing it and shooting it into the air that we breathe? Yes, no matter what the material is, that is dangerous, so you need to protect yourself. I also think that those who brush on any finish other than shellac made with grain alcohol would be smart to use an organic vapor respirator, because there are solvents that are not good for you at all, even in waterborne finishes. So, the risks are not just from using UV cured finishes; they are from spraying anything, and from using any solvents other than grain alcohol. I protect myself pretty well. I have a spray booth that moves air at 150 fpm, which is replaced with fresh air from the outside world, and I wear a PAPR and a Tyvek suit. When curing UV cured materials, I have the appropriate visor, and I cover every inch of my body. The good news is that these materials (both UV cured and catalyzed) are only dangerous while mixing, spraying and curing. With UV, that can be a pretty short period of time, as in minutes. Before that, the materials are in cans, and after that, they are inert.

If there are customers who are willing to pay a lot of money for a guitar, and live with the guitar being very prone to damage from chemicals or the wrong type of sweat or body oils, that's great. Seriously. But I think there are also different customers who would really like to have a great sounding guitar without worrying about their sweat or body oils eating the finish (some folks have that type of body chemistry), or taking their guitar to an outside event and the finish being harmed by bug spray or sunscreen, or the finish being shocked by extreme cold, etc. Just speaking for myself (I do try to consider what I would do as a buyer), if I pay thousands of dollars for a guitar, I want it to hold up to wear and tear, and I don't want to have to baby it. Maybe that's a different type of customer, which is fine. Again, I'm big tent. But I don't think those customers should be led to believe that the only way to have great tone is to put on a fragile finish. Again, with the James Olsons and Kevin Ryans and Froggy Bottoms , etc., of the world out there making great sounding guitars with very durable finishes, we know that if there is a tonal sacrifice associated with using a more durable finish, that sacrifice can be rendered de minimus by keeping the finish thin.

I want to build more durable guitars because, for the type of buyer I am thinking about, a more durable guitar is more likely to be played somewhere beyond the couch, and I want my guitars to be played.

I've mentioned this before but I spent about 2 years researching and experimenting the hell out of this very topic. The trigger point for me was that Joe White stopped doing finish work (I sent my guitars to him for over 10 years) and that I occasionally French Polished just the tops during that time period and each guitar had an openness and maturity that was absent from the polyester topped guitars. And it was definitely a noticeable difference -- not massive but noticeable. My guitars still sounded exceptional with the poly but the FP guitars were clearly better sounding instruments. What I'm currently doing with urethane gives me the same sound I got with French Polish. It is incredibly challenging but it is possible to use urethane or lacquer and not compromise on tone.

Read this page on my website for a summary of my thoughts:
http://fayguitars.com/Guitars/finish.html

My opinion is exactly that -- an opinion. But I build responsive and highly refined guitars at the highest level and so I feel that it is well-informed opinion. IMO, the bottom line is that for most finish types so long as you keep it under 3 mils on the top (and fairly thin elsewhere as well), then it just doesn't matter all that much. Will shellac be the best sounding even at 3 mils. Yes, it will but in my experience the difference is barely even perceptible. 3 mils is about as a thick as a piece of Scotch tape. The problem is going over 3 mils. It's like that magic point with purfling thickness where you can bend it into any shape you want but go another 0.005" thicker and it not longer bends the same way. It's the same principle here. 3 thousandths of an inch leaves the material ultra flexible but go any thicker and you absolutely feel more resistance to bending.

For a glossy finish, you have to be meticulous to get 3 mils. The wood surface must be absolutely perfect beforehand. The finish leveling must be absolutely consistent. For a material like urethane which doesn't burn in -- 3 mils takes an exacting process with no room for error. And ideally, you want to be closer to 2 mils if possible. If you can do this, then that open, mature, and warm sound we all notice with French Polished soundboards will occur with both lacquer and catalyzed urethane. In other words, the tonal compromise is gone.

Personally, I love shellac. It is an incredible finish but it is so much more delicate than something like lacquer or urethane.

One last thing, the only way to achieve a 3 mil finish on the top is to utilize something like Frisket tape. You mark off the bridge and fretboard area. When leveling the finish (before the last spray session) I make sure to sand evenly and once I'm level with the 2 mil Frisket tape -- I keep going as much as I dare and hope to take the finish to 1 mil or even less. Then the subsequent finishing session's goal is to add about 3 mils of finish and leave only 1.5 mils of that 2nd coating session after buffing -- giving you about 2 to 3 mils total.

If doing gloss on the regular, one of these would probably be a good investment…

https://www.defelsko.com/resources/dry- ... substrates

I may get one of those eventually but they're just so expensive. And ultimately, even spraying and even sanding does yield an even coating thickness. But it sure would be useful, especially during the sanding of the base coat.


One thing I would like to say is that I believe every single builder should French Polish a few of their guitars at some point. This will help you understand the true potential of your guitars and whether your current finishing method is limiting your ceiling.

The only published article I know of comparing the properties of various finish materials on wood was by Martin Schleske. He's a violin maker who holds both a PhD in physics and a master's rating from the German violin makers guild, and is best known for making 'tonal copies' of old master instruments that are very hard to tell from the originals, so he's qualified. From various writings of his that I've seen he seems to feel that there is no finish that helps the sound, but that some hurt it more than others, and that less is better, no matter what the finish is.

I, too, wish that shellac was a bit more durable, particularly as regards body chemistry. It does improve with age, but it takes about 75 years for it to become bullet proof. Since my customers, patient as they are, don't want to wait that long, I've been using other finishes. Having made nitrocellulose (as pat of a science project years ago) I know enough about it's chemistry to avoid it. I've been using one or another oil-resin varnish for decades. The oil content does add a bit of damping, but when kept thin (that magic .003" or less) it's not objectionable. My main beef is that whenever I get practiced at using some varnish it's discontinued, so I have to find something else. I brush it, and, yes, it takes a fair amount of practice to get a nice uniform coat. But it can be done. A hard short oil (rubbing) varnish is no more protection against dings than French polish, but it will usually be more scratch resistant, heat resistant, and chemically stable than shellac.

I don’t believe there currently is, nor ever will there be, a perfect finish. In shellac’s favour, much of the general wear and tear that a finish might sustain over the years can be improved, in some cases fully repaired, with a few sessions of polishing. I feel this is a low maintenance cost to the owner of a high-end instrument, if they were to have a luthier do a few hours of polishing every several years.

I generally shoot nitro. It’s what my customers want and all it’s “undesirable” aging characteristics have, by the miracle of the marketplace, been transformed into benefits.

Left to my own devices I would use a lot more shellac on my builds. I use it constantly in my repair work. If every finishing product ever invented disappeared tomorrow, we’d be ok as long as we still had our little beetle buddies.

At the risk of belaboring my point, many of the guitars I referenced were finished with shellac and have fantastically durable finishes. The knocks against the durability of the shellac commonly used today are warranted. The shellac used in the guitars I mentioned was heat processed. With the exception of button lac and handmade shellac today all shellacs are solvent extracted. My work with button lac has confirmed its superior hardness and toughness when compared to super blonde or the like. It's also entirely likely other gums like sandarac and mastic we're incorporated into these durable polishes, although it is unlikely Lyon & Healey would have used anything too exotic.

_________________
Stay with the happy people.
--Reynolds Large

Finishing is as much an art as science and not all finishes are the same.
I gave up on shellac as it isn't very durable. I love French Polish on classical's but still not my forte .
Lacquer has been around and Martin started using it in the 20's. Yes it is a great finish but lets look at this from a home shop point of view.
There are a variety of finish materials and many ways to apply them , sand , buff and polish.
You can rub , brush on or spray and if you spray please get a good spray gun. Cheap tools are costs good tools are an investment.

Lacquer needs to be handled properly as it is not a health food. You need a proper booth and you
do need protective wear when using it. RH control mix and thinning , along with cure , level sanding are all part of finish work.
Most beginners are too heavy on finish and too light on level sanding and buffing , so accept there is a learning curve.
It has a big advantage in its repairability and and use in production facilities but again there are a lot of VOC's that are not good for you

Shellac French polish
worth trying but not my favorite finish

Now today UV cured water based lacquers and other more environmentally friend finishes are out there so educate yourself
and find what will work for you. Not all modern finishes will allow repair so that has to be part of the equation. We all have opinions on what is best but the fact is , Technique is often as important as the material .
Water based when they first came out had a weird blueish hue to it. I am experimenting with Emtec 9000 and Akzo Nobel's finishes
and find them easy to work with and they are much clearer. The AKZO drys hard and I am happy with the initial results. Sealers are part of the process as is filling and staining. Learn the steps.

Also note when we are talking shellac we are talking about making our own and not Bullseye . I use flakes and mix it with everclear. Yes Shellac makes a good sealer.
My 2 cents. Just find what works for you and your situation. Sometimes farming out finish work is the best way to go but learning how to do it can be frustrating or rewarding.
A few things that helped me were a good buffing wheel and a good dual action hand buffer. Learning this process is another exercise . On you tube there is a group call the ( finish society ) its worth a look , granted its mostly on cars but the detail process is similar to what we do.

Now I agree finish is important but your wood joinery is more importanter .

_________________
John Hall
blues creek guitars
Authorized CF Martin Repair
Co President of ASIA
You Don't know what you don't know until you know it

I only use shellac based spirit varnish on my restorations. I brush it on and dampen the shine with fine steel wool, followed by some hand polishing with a dry cotton rag to regain some of the shine. This varnish is a bit harder than real French polish, and oh so easy to apply. A day or two it all that it takes, two or three layers can be put on in one day. After that, it will take a couple of weeks until the lacquer hardens.

I buy it ready-made from the JOHA website, https://www.joha.eu/en/varnishes/spirit ... arnish-ia/

I can't be more happy with this varnish, no fumes, fast drying, easy repaired, thin layers and perfect on an old guitar.

_________________
New will change the old,
turn to ashes or gold

http://www.gammelgura.se

Tom if you have one please post a pic of your a FPed guitar like the one(s) you brought to our place when we met you. Your FP work was about the very best I've ever seen, beautifully done, warm as can be too. Thanks!

That is interesting, Roger. I looked at their MSDS and of course the component resins were not listed (no surprise). Ethyl alcohol is the only hazardous substance listed. So that looks good. My only worry about buying it in the US is shelf life. Buying from shop with high turnover of inventory would be essential.
I'm also interested that you state it is harder than real French polish. Could you please elaborate a bit on how you came to this conclusion? Was your control freshly dissolved shellac flakes? What type of oil did you use in applying your real French polish? Did you notice this difference over more than one instance?
I'm not trying to interrogate you! The answer to these questions might impact your observations comparing the JOHA the real French polish. Thanks.

_________________
Stay with the happy people.
--Reynolds Large

Thanks, Hesh. I'm finishing up an all French polished steel string presently and will endeavor to get some pics taken, although I am a Luddite with these sorts of things.

_________________
Stay with the happy people.
--Reynolds Large

They have two versions of the varnish, the more expensive one have more expensive ingredients. I buy the cheaper version since I'm so satisfied with it. I keep the 1 liter metal cans in a refrigerator in the shop, and I have not seen any degradation after storing a can a year or two.

It is harder than fresh French polish from the start anyway. In my usual way I have not done any scientific experiments, I go with the feel, comparing with the few times I have actually done a real French polish. The varnish is really dry to the touch after about 6 hour or so, but it will keep on getting harder for about a month and probably longer than that. I wait a week until I polish the varnish with a dry cloth, before that I can't get enough shine and I can feel that the varnish is not bone dry at that state.

It is not as hard as nitrocellulose lacquer, but in my opinion harder than pure shellac (until the shellac is 75+ years!). It also don't react much to water, I can use plenty of water when cleaning up later on without any problems.

I guess the only way to really know if it's suitable is to try it out. I know it works perfectly for me, but then again, I'm not after a mirror like finish on my old guitars - actually the opposite.

Here is a recent slide of a newly painted and semi dry neck (the body with original nitro lacquer is not varnished). The varnish is very shiny without dulling down with steel wool!

_________________
New will change the old,
turn to ashes or gold

http://www.gammelgura.se

Hi Roger, the spirit varnish interests me, a lot. If you don't mind I have a few questions. Do you seal with shellac? When needed are you able to add color? What kind of brush do you use? Thanks.

Edit: I've been French polishing with Royal Lac and although I like the results the arthritis in my hands is slowly getting worse and a user-friendly brush-on finish would be really nice.

_________________
Steve Smith
"Music is what feelings sound like"

I don't seal with shellac, there is plenty of shellac in the varnish. But if you are on the hunt for that mirror result, then you can save a lot of time by doing the grunt work with varnish and top it off with some layers of French polish. On the same JOHA website you can find spirit solvent colors in powder form. The neck in the picture is painted from bare white wood with one of the colors and about 5 layers of varnish - still very thin. I started off with a layer of spirit primer (also on the site), this layer dries very fast and gives a good base for the varnish.

I use the biggest varnish round brush I can find, almost an inch in diameter. They are hard to find. I also sand between layers with 600 paper and/or steel wool. Sometimes, if you are not careful, you will get some "run out" or droplets, they are easily sanded off and can be painted over with a thin new layer of varnish.

_________________
New will change the old,
turn to ashes or gold

http://www.gammelgura.se

Thanks Roger, I’m going to give it a try.


Steve

_________________
Steve Smith
"Music is what feelings sound like"

I'm glad you do, I hope you get the same good result as I!

I can add that you really need to be fast with the brush, when you start brushing, never let the brush stand still until you're done.

Keep a keen eye for any "runs" and attack them as quick as possible with the brush. On the neck, the slots for the tuners is a trap where the varnish can run to the other side, I keep the brush loaded as little as possible on the head and keep turning the neck around to kill any excess varnish. Always draw the brush away from the body, start the strokes from the inside and finish the stroke in the air. If you go the other way, there is a good chance that you will scrape off some varnish and get a "run" on the side. When I do the brushing on the top and bottom, I always check the sides for runaway varnish. The rim of flat surfaces can also easily collect excess varnish when the brush leaves the surface.

The brush is cleaned with desaturated spirit, you can also buy pure 99% alcohol on the site.

Many thin layers are better than one thick layer, especially if you have color in the varnish.

The varnish dries to almost no thickness, violin makers can put on 20 layers without getting a too thick varnish.

The varnish shrinks when drying, with an old tired lacquer, a couple of layers of spirit varnish on top of it will give more trebles to the guitar.

I use the varnish on both old nitrocellulose lacquer and old Frensh polish. The varnish gets stuck on both.

I use a U-shaped clamp through the soundhole as a handle when doing the brushing.
https://www.amazon.com/BESSEY-TOOLS-LMU ... B002RJ82YI

_________________
New will change the old,
turn to ashes or gold

http://www.gammelgura.se

Well, such a shame. I filled out a nice order for about 40 euros but shipping to the US was 280 euros. I expected shipping would be fairly high but that's too steep for me, I suppose it's due to the hazardous material charge.

I found another source in the US: International Violin Supply in Baltimore, MD. I'll get some from them.

_________________
Steve Smith
"Music is what feelings sound like"

I think metropolitan music in vt carries it as well.

_________________
Stay with the happy people.
--Reynolds Large