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[QUOTE=TRein]   Sprayed shellac will not harden to the same degree padded FP will.
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Are you sure? I sprayed a shellac finish on a F-style mandolin recently, and the finish seems pretty hard. I have never done a FP finish that I can compare it with, but I have not read a report from people who have done both that indicates that there is a difference in hardness.

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Rian Gitar og Mandolin

I'm also interested in what people have to say about Behlen's Rockhard.
I've been planning to use Al Carruth's method described in this thread:

http://luthiersforum.com/forum/forum_posts.asp?
TID=2098&KW=rock+hard+varnish#forumTopJames Orr39083.8478240741

I've been using Rockhard varnish on all my recent builds. It is a pain having to sand between every coat but I love the look.    It has a nice deep gloss without the plastic look of some finishes and I love the color it turns spruce tops - they look like they're fifty years old. I use zpoxy on the back and sides and several coats of padded-on shellac on the top to keep the varnish from penetrating the top wood.

                   Peace, Paul

Following up on Jon's question... what's the difference in just padding on some shellac and a true FP, besides the difference in thickness of the finish? What, if any, are other pro/cons?

Using walnut oil as a lubricant creates a type of emulsion that you don't get by just brushing it on. When I final polish with Novus 3, I can smell a bit of the walnut oil coming off the finish. Using linseed oil can create a disaster, because if it gets entrapped in the finish, it will turn white when the player perspires on it. Could have something to do with molecular weight. I don't know for sure, but walnut oil causes no problems with entrapment.
Arnt, I got the info about FP becoming harder by being compacted by the polishing process from Richard Brune. It seems to make sense. Also, proper FP technique is putting the shellac on as almost a vapor. If you can't see the alcohol flash off immediately when padding, something is wrong. Brushing or spraying on softens up all the layers you have already applied and maybe not all the alcohol leaves the final film?
As far as I know a fair number of violin makers use FP as the final gloss over a supple oil varnish. However, I could not sell guitars that look like the "aged" violins most contemporary fiddle makers are putting out. So, in theory, you could use FP as the final gloss over a harder varnish. It still will require maintenance to keep it looking good. Probably a lot as the film thickness would need to be very thin.
I am hoping some of our European builders will chime in about some of the shellacs they are using. I have no doubt that there are way more shellacs available than what come into the US. Button lac has the reputation of being harder than regular shellac due to the heat polymerization it undergoes during processing. The recent page I posted a link to indicated that handmade shellac is melted and forced through a canvas bag like button lac, but stretched into sheets rather than dropped on a metal sheet to form "cookies" as button lac is. It would be interesting to know how recently solvent extracted shellacs have been the norm. I am brewing up a batch of button lac at present to try out.

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Stay with the happy people.
--Reynolds Large

I have used the Behlens Rock Hard Tabletop Varnish and agree with Paul's comments above. I use the John How mixing recipe that I pulled out of the archives, also MichaelP has provided some insight into this finish as well. I love the vintage look it provided and from all indications is very hard and durable. Like Paul stated, sanding between each coat lightly adds some time and hassle factor but the final result is really nice. I am using it on another right now.

Mike

[QUOTE=Don A] Okay finish gurus, why not French polish over a couple of basecoats of lacquer? Seems the lacquer would provide the protection needed for steel strings and picks (plectrums) and the French polish as topcoats would be easy to repair. Anybody doing this?[/QUOTE]

Don, you are raising a very valid and interesting question here, i've been wondering the same thing after seeing Dudenbostel's technique of French polishing over varnish, his results were quite amazing, i'll be giving that a try on the current build and will let you know how it turns out.

Serge

You guys have made this a great thread.

Alain,,
I am actually going to pattern my accustic after Buddy Guy's Tele, and in place of the polka dots-holes

Ktm 9 is one of my standard finishes. I like it and have no softness issues. I also offer French polish, Nitro, and combos of French polished tops with other back and side finishes. I will continue to offer KTM 9 as my standard finish

Someone said that French polish offered no protection. IMOP, this is far from true. It offers a very good environmental protection to just about everything but alcohol. Depending on how thick you make the film it offer darn near as much dent protection as nitro. Yes flat picking and some finger nail marks may mar it but that should be only in the film and not the wood. Plus an informed average Joe can repair those marks in 10 min. you can't say that about lacquers.MichaelP39084.3876041667

I love this thread...we should have a section just for discussion of the various finishes...or a library

After doing an entire guitar in FP, I swore that I'd never do it again due to the elbow strain it caused me. Recently, while building 3 at a time, I decided to pad on shellac to protect the tops. Well, now that I know how to do the process it really wasn't all that bad...and the beauty of the finish was striking...and this was just a few sessions only to protect the surface. So, I decided to only lacquer the back and sides and do more sessions on the tops. I agree with others who stated that tops produce better response and tone. While it won't match the back and sides for gloss and protection, FP has a beauty of its own that really is more vintage looking. FP actualy seems to become more a part of the wood and doesn't appear as a coating like other finishing materials...and it's noticeable.

For those who are doing this for the first time, pay a lot more attention to pore and gap filling...the surfaces must be PERFECT before you start the FP process. And digest everything that Michael has ever posted on the techniques and tricks...I think he's seen it all!

My question on FP has to do with a comparison between the Zinnser de-waxed canned stuff vs. dissolving the flakes in ETOH. I've used the canned stuff so far but was thinking of going to flakes. Can anyone describe the difference expected as far as quality of finish, durability, application, etc.? Also, the first 2 sessions were with the canned...can I complete with dissolved flakes or should I sand off and start fresh?

TRein...your experimentation with shellac is interesting. I'm looking forward to more of your results and comments.

One more thing...The 2 Parlor guitars I finished with KTM-9 are now 2 years old and are played regularly. They look great and seem to have no hardness issues. I believe that it takes months for most of the finishes to completely cure out and we get into trouble when we try to speed up the wet sanding and buffing process. With KTM-9, I forced myself to wait 2 weeks before even touching the surface with sandpaper. I believe that waiting even longer would be better...but that's the perfect world JJ Donohue39084.4411921296

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JJ
Napa, CA
http://www.DonohueGuitars.com

I have used french polish on a number of my steel strings. I used the John Greven instructions in the old LMI loose leaf catalogue. he adds a small amount of walnut oil to the shellac and uses walnut oil as a lubricant as well. Walnut oil dries very hard and combined in the shellac makes for a hard, durable finish, and if you use pure ethyl alcohol as the solvent it is totally enviromnently friendly, although drinking some of the alcohol while FPing can affect the quality of the work.
My only problem with FP is the time it takes. That is why KTM 9 is my finish of choice.

JJ,
My take on your question is that if you are looking for a vintage appearance the Seal Coat is great. premixed, 50% amber 50% blond mix gives a nice light amber hue. If you want a more garnet or a true blond hue then you will have to mix your own.

The other thing that I like about Seal Coat is the shelf life.

Michael...so you feel there is no qualitative difference between the flakes and Seal Coat? If not, then I'll continue with the canned stuff. It really is convenient.

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JJ
Napa, CA
http://www.DonohueGuitars.com

Anyone interested in French polishing would do well to check out Robbie's finishing video or take a class from Marshall Brune (I did the latter, I don't have the dvd but Robbie was in the FP class with me). This method is so much easier and quicker than the Milburn tutorial or the Fernandez video LMI sells. Search for some of Roger Labbe's posts here, too, as he's taken the class and posted pictures of some of his work.

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Jonathan Kendall, Siloam Springs AR

I still say FP offers little to no protection, regardless of the thickness of the film. You should see the top of my first guitar. True, I have acrylic nails, use a thumb-pick and I can be quite agressive while playing, so I guess the wear I put on a guitar is probably not considered 'normal', still the top looks like it's been through heck. (lately, I have been playing a few hours a day). I doubt I would have so much damage if the finish were nitro or poly...

Now don't get me wrong, I love FP, but like I said, seriously consider using a pick-guard if you do.

Now, ask me about the tone...

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I'd like to be able to prove, just for once, that money wouldn't make me happy...

[QUOTE=JJ Donohue] Michael...so you feel there is no qualitative difference between the flakes and Seal Coat? If not, then I'll continue with the canned stuff. It really is convenient.[/QUOTE]

No diff in the quality of the final product IMO, out side tint. After the volatiles flash off you are left with 100% wax free shellac. Like I have said before it is my standard FP mix unless I want a different hue.

[QUOTE=Don Williams] There is tremendous evidence that shellac is the most acoustically transparent finish available.[/QUOTE]

Don,

I used to think that but now I am not so sure. I finished my cedar/maple Grand Concert with FP but found that my arm was reacting with the finish on the bass side lower bout. I stripped the FP off and re-finished with 4-5 thin coats of a pre-catalysed lacquer (this is not the acid catalysed stuff that you mix with a seperate catalyst, but the stuff that has replaced nitro here in the UK. Comes in one can and the coats burn in to each other like nitro). I also took the opportunity to use Z-poxy for the first time under it on the back and sides. The lacquer was rubbed out to a sub-gloss finish similar to Lowdens.

The sound when I strung it up was much better than with the FP to my ear. Could be that the guitar was still in the opening up phase or could be my FP was not good or hard enough. I've used this finish on 4 or 5 instruments since and the results sound wise have been very pleasing.

I also used to think that no finish at all (the wood polished up) was the best sound but I now believe that the finish put on the wood actually makes the guitar sound better. There is I believe a sort of sound/finish thickness curve that shows an improvement in sound as coats are applied up to a certain thickness and then a drop off in sound quality as the finish thickness increases from there.

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Dave White
De Faoite Stringed Instruments
". . . the one thing a machine just can't do is give you character and personalities and sometimes that comes with flaws, but it always comes with humanity" Monty Don talking about hand weaving, "Mastercrafts", Weaving, BBC March 2010

I'm known as a fan of French polish, I like the fact that I can apply it without having to look like Neil Armstrong. I like the fact that it's a very personal process that keeps me very much in touch with the wood, rather than at arms length (or however far away you are when spraying).

I think that the difficulty of the whole process has been blown out of proportion. When it comes down to it all your doing is rubbing shellac onto wood. As with all things to do with building a guitar or lute , if you break it down into individual actions it's very simple. If you looked at a pile of planks on the bench and pictured the guitar you've got to make them into it is very daunting indeed and you probably wouldn't start, but if you break the job down into each small separate step it's not so hard. Same with French polishing.

I've FP'd about 30 instruments now, and as has been said, like the sheen that it gives the wood. As to it's durability, I have only had to refinish one top, and that was one I lent to my son! If applied correctly with enough pressure on the padding, then I believe it builds into a relatively hard and durable finish. Will it stand a flatpick? Don't know, don't know anyone that owns one! But I assume a flatpicker would have a pickguard. And anyone that rests a fine instrument against a belt buckle should be given an Ovation!

I used to make up my own shellac from flake and DA, however, on the initial recommendation of our full time French polisher at the University, I have switched to the Liberon de-waxed Special Pale. I am exceptionally pleased with it, I get a good build and final lustre, it is just good quality flakes and alcohol, without the fuss. I just buy a new 250ml bottle for each guitar, the previous bottle gets used for washcoats etc. Once I start to apply the shellac that is the last time that my guitar sees abrasives, I have never found the need to level sand it and I certainly do not buff it out, after glazing, that's it, just a nice sheen.

I can get quite intense about this, did you guess?

ColinColin S39084.7504513889

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I don't believe in anything, I simply make use of a set of reasonable working hypotheses.

[QUOTE=JJ Donohue] Michael...so you feel there is no qualitative difference between the flakes and Seal Coat? If not, then I'll continue with the canned stuff. It really is convenient.[/QUOTE]

JJ, check with BobC as there is another option. I haven't tried it but I believe Bob has given it a go and if my memorry is correct he liked the product. It is Oxford Ultaseal-WB, a water based shellac from Target Coatings.

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Don Atwood
Arlington, VA

Water-based! I'll look into it. Thanks, Don.

Would that mean I could expose my guitars to alcoholics again? I guess as long as they don't have water in proximity to chase it down. Some of my best buddies are single-malt Scotch guzzlers.

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JJ
Napa, CA
http://www.DonohueGuitars.com

There are people FP'ing over epoxy. This is the same as doing it over lacquer or any other finish. It works fine. I once did a repair on a UV cured Taylor finish. I went over the repair area with cat urethane then hid the witness lines with FP. Works like a charm.   

[QUOTE=Ken Franklin] I've used KTM, catylized urethane, french polish, precatylized lacquer, True Oil, and varnish. They all have their disadvantanges and I hate the outgassing and smell of nitro. I'm presently using a catalyzed car clearcoat finish applied very thin so it won't affect accoustics.
[/QUOTE]

Isn't a car clear coat just a cat urethane? i.e. 2K urethane

[QUOTE=Hesh1956]Another question I have is even though you don't want epoxy on guitar top if the rosette is in need of pore filling (BRW) can you just fill the rosette area in the traditional manner with epoxy and then use a thin wash coast with 50% DA 50% epoxy on the rest of the top?

Sorry for the partial highjack here too...... [/QUOTE]
You could also just use epoxy to pore fill and/or even level the rosette and then sand it back til it is clean. No need to put 50/50 on the entire top.

I FP'd the top of a SS (learned from Robbie, thanks ) and put a
clear pickguard on it. It has held up beautifully to lots of flatpickin' and
you really can't see the pickguard anymore than you could on a high gloss
nitro finish. I got the FP really glossy too of course with the ol' buffing
wheel.SniderMike39084.8625810185

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Mike

"The Dude abides. I don't know about you but I take comfort in that. It's good knowin' he's out there. The Dude. Takin' 'er easy for all us sinners. Shoosh." The Stranger

This is my exact problem now. Taylor 810 with lots of surface problems. I have sanded down quite a bit and drop filled with nitro. But, I am worried about the build and finish layer. I realize that nitro (or anything else) will not bond with the uv polyester. So I am looking for a solution (besides polyester). I was thinking of pre-cat lacquer. Ideas welcome.

Mike