Shellac for french polishing

Sorehand · #1 02-24-2016, 08:06 AM

I have been French polishing a current ukulele build. I have been having good luck using a solution I mixed from shellac buttons. Nice and dark and giving an "aged color". I have been watching some folk in a guitar building class using Qualasole for French polishing. It appears to be easier to work with than my home mix. No oil required or extra alcohol for spiriting away the oil.

What I am wondering is what are the trade offs with using this premade product. I know the obvious one is I can control the color with my solution. Are there other positive or negative issues that you folks might know about.

WaddyT · #2 02-24-2016, 09:20 AM

There are several pre-mixed shellac products that work, including Zinsser Seal Coat, which is a de-waxed shellac. Another good product is Royal-Lac which is available in a number of different natural shellac colors, Orange, Garnet, Blond, and a couple of others. They also offer a Seal-Lac product which has more solids added. The Royal-Lac products have resins added to make the resulting finish harder and more resistant to alcohol, perspiration and water damage. It works fine, and a number of builders, including me, use it. Results are quite good. I have no connection with the maker of Royal-Lac, just a satisfied user. The owner is working with a number of builders to come up with a satisfactory spraying solution. He is a very conscientious person interested in the satisfaction of his customers.

redir · #3 02-24-2016, 10:02 AM

Hey Waddy I've been thinking about giving the Royal Lac a try. Do you apply it the same way as traditional FP?

I've also looked into U-Beat but I cannot figure out where to get it. LMI has an article on it but son't seem to sell it.

Can these hard shellac's be repaired easily?

As for the Qualasole I've never used it but IIRC it's either used or one of the recommended finishes in one of Sloane's books. I get the feeling though that it's not generally accepted as a guitar finish. Having said that you probably could add color to it. I would not at all be surprised if it's not any easier to apply then regular FP too. Personally I like using oil as it just makes everything so smooth and less tacky.

Sorehand · #4 02-24-2016, 10:27 AM

I have used U-Beaut shellac in the past. It seemed very similar to the mixture of shellac that I am now using. Oil and alcohol were needed. It has become difficult to find in the US now that LMII is no longer importing it. The claim to fame is the polymer crosslinking formula they use. Supposedly makes it more resistant to alcohol when it is cured. Have not tried spilling a drink on my guitar yet. No doubt it will eventually happen!

arie · #5 02-24-2016, 01:46 PM

Quote:

Originally Posted by Sorehand

I have used U-Beaut shellac in the past. It seemed very similar to the mixture of shellac that I am now using. Oil and alcohol were needed. It has become difficult to find in the US now that LMII is no longer importing it. The claim to fame is the polymer crosslinking formula they use. Supposedly makes it more resistant to alcohol when it is cured. Have not tried spilling a drink on my guitar yet. No doubt it will eventually happen!

us distributors:

http://www.ubeaut.com.au/distribs.htm#USA

redir · #6 02-24-2016, 01:50 PM

Cool thanks Arie.

WaddyT · #7 02-24-2016, 09:21 PM

Quote:

Originally Posted by redir

Hey Waddy I've been thinking about giving the Royal Lac a try. Do you apply it the same way as traditional FP?

I've also looked into U-Beat but I cannot figure out where to get it. LMI has an article on it but son't seem to sell it.

Can these hard shellac's be repaired easily?

As for the Qualasole I've never used it but IIRC it's either used or one of the recommended finishes in one of Sloane's books. I get the feeling though that it's not generally accepted as a guitar finish. Having said that you probably could add color to it. I would not at all be surprised if it's not any easier to apply then regular FP too. Personally I like using oil as it just makes everything so smooth and less tacky.

The Royal-Lac can be wiped on to build doing a coat every hour or so, then polished like regular French polish to finish it up. After a couple of coats you can level with 400 grit, lightly. Then continue to build. Leveling when needed. It has a cross linking process as well, which is what makes it more durable. The additives are different from U-Beaut. From what I've been told, and I'm no chemist, Royal-Lac does not contain plasticizers, but has resins added to accomplish the hardening and cross linking.

As to repair, it's not hard, but you do have to sand a little to scuff the surface if it's been more than a month. The new finish will not melt into the old finish.

B. Howard · #8 02-25-2016, 07:32 AM

Buttons are the traditional materials for FP. They are polymerized in the process that makes them and therefore tougher than any dewaxed shellac or other all shellac product. This was the finish used on ballroom and gymnasium floors prior to the invention of polyurethane in the 1950's. So that speaks volumes as to the toughness of this type of resin.

I believe qualisole and others like that have modifiers added to them, who knows what is actually in them.

Here is a link to one of my presentations on traditional FP with buttons where I explain a bit about types of shellac, dewaxed vs. waxed etc.

PhilQ · #9 02-25-2016, 08:30 AM

Great presentation, Brian. Thanks for sharing!

redir · #10 02-25-2016, 08:47 AM

Agrees, I liked that video as well. I guess I always thought that dewaxed shellac was the only way to go for guitars. I've never tried the button shellac before.

I do tend to agree that FP finish is a tougher finish then most people are led to believe. I built a Semer guitar for myself a few years ago with FP finish and that guitar has been to hell and back and still looks good. Granted there are pick scratches and so on that a hard poly finish would simply deflect but I think, as many others do, that the thin FP finish is the best finish you can get for good tone and is worth it.

I also found it interesting how you charge the muneca through the back side, so to speak. I've always dropped shellac on the dolls head then padded it out on a surface.

Sorehand · #11 02-25-2016, 09:03 AM

Thank you Brian. You answered questions that I did not even know I needed answers for! I will go forth and not even consider using anything but button shellac. No oil!? I have never heard this before. I can barely wait to try it. Thank you for sharing your knowledge.

Imbler · #12 02-25-2016, 09:04 AM

I have used both unadulterated shellac flakes in alcohol, and Royal lac. I'm a big fan of Royal lac for myself because my body chemistry is hard on regular shellac. Royal lac is impervious to most solvents and applies like regular shellac for FP so I use it now

If the guitar is for you, and you know your chemistry is not hard on shellac, I'd use regular shellac because touchups are easier. With Royalac, after a month or so, you need to redo a complete surface to do a touch up (sides, top, or back for example), as after it cures it will not melt back into itself, and you need to scuff sand an entire surface and coat it to avoid witness lines,

I do all my guitars in Royal lac now, because I don't know where they will end up, and the increased durability is quite remarkable at a reasonable cost.
Mike

Ned Milburn · #13 02-25-2016, 12:02 PM

It is pretty common for FP pros to avoid over-the-counter products with a long shelf life. They will necessarily require the addition of chemicals to stop the shellac solution from going bad, and it seems likely that this will affect the quality of the final polish on the instrument. (Good or bad, I don't know...)

I am re-quoting part of a post I made on another finishing thread since it has bearing on this thread's OP's query. Apologies in advance to those who have to suffer through reading this portion twice.

It has come to my knowledge via a conversation with Serge DeYonge that many traditional blends for French polish were not simply shellac and alcohol. More likely than not, traditional FP recipes included various different resins (based upon availability and knowledge, choice, and preference by the artisan). The addition of certain resins can aid in the durability of the finish, as well as its shine and even the way that the underlying wood develops a patina by slowing or speeding patina development.

I would expect that the highly refined (and nearly "pure"??) shellac flakes that are available today were not available in days of yesteryear, and that the choices were button lac or the dark waxed flakes that often seem to us now like a low grade lac product. Again, I highly expect that it was not the quality of the raw shellac flakes or button lac that determined the end quality of the artisan's finish; rather, it was the recipe and process the artisan used which determined the quality of his finish.

If you do a search for "violin shellac varnish recipes" you'll come up with a whole lot of interesting and enriching information. Here is a link that is particularly interesting to me.

http://www.kramers.org/finishes.htm

Regarding the OP's comment/question about oil versus no oil... I have successfully applied a FP finish on a test piece with no oil. Truth is, it turned out very well. That said, applying the finish with no oil on a full guitar would present a serious challenge, and I used a much thinner shellac solution, so to do this style regularly, I would end up using a whole lot more alcohol. Once you get the hang of FP using oil, it is pretty hard to screw up. Using no oil was always like holding on by the seat of my pants. Anything is possible, however, and I've heard of people using no oil as their regular FP routine.

PhilUSAFRet · #14 04-18-2016, 09:55 AM

https://www.youtube.com/watch?v=KXRdJ6psTLg

charles Tauber · #15 04-18-2016, 10:24 AM

Quote:

Originally Posted by Ned Milburn

It has come to my knowledge via a conversation with Serge DeYonge that many traditional blends for French polish were not simply shellac and alcohol. More likely than not, traditional FP recipes included various different resins (based upon availability and knowledge, choice, and preference by the artisan). The addition of certain resins can aid in the durability of the finish, as well as its shine and even the way that the underlying wood develops a patina by slowing or speeding patina development.

Perhaps drifting a bit off topic, but....

One way Serge has found - an old European recipe - to toughen shellac and extend shelf-life is to add sandarac and benzoin resins: 24 g shellac, 3 g sandarac and 3 g benzoin, boiled for 5 minutes. He stated that he no longer uses sandarac due to allergies some people (players) have to it. A Canadian source for the resins - and other interesting things - is http://www.kamapigment.com/index_en.html.