French Polish

[David Lay]

I have searched, but cannot find where others have made recommendations for applying shellac by the "French Polish" process, though I remember reading some.  I tried the typical instructions found on-line and by an author, Tage Frid, using a 2# cut, a pad, and sometimes a bit of oil, but my result was bad.  More recently, I went with what another author, James Krenov, advised using what is a 1# cut or even more dilute, and no oil.  (Lots of coats, but then one web source recommended 30 coats with the 2# cut). I like the result. Frid wrote that for traditional FP, filled pores is usual.  I left my mahogany with open pores and it is not glossy like I would expect from traditional FP. 

I used orange flakes in "190 proof denatured ethanol".  (Ethanol will distill to 95% ethanol/water easily.  Getting that last 5% out is difficult, and once a container of it is open it will absorb water from the air and be 95% quite quickly, making it 190 proof.)  The labeled ingredients of my alcohol are ethanol and water, so I have no idea what makes it "denatured". 

Zinsser shellac from my hardware store gives a wide range for how much shellac is in their product, so it might be 2# or 4#.  It lists up to 10% propanol as an ingredient, but nothing more scary.  Propanol (rubbing alcohol) is a common denaturing agent. Shellac is said to go bad if not fresh but Zinsser does not have an expiration date on the can (??).  Krenov thought the canned product an OK option provided it is diluted and strained. 

To be safe, I used flakes and as pure an ethanol product I could buy, freshly mixed.  So, if I filled the pores and went to 30 coats or so of my 1# cut, would I get a glossy french polish?  

Also, the use of oil seems counter-intuitive.  It seems it would polute the finish since alcohol and oil are miscible.  What can be said about this part of the process?

[Łukasz Martynowicz]

The process of French Polish I was taught goes like this:

- first you prime with undiluted solution, wait 24hrs, lightly sand with fine grade steel wool and then rub filler into the pores with another coat of undiluted shellac and sand again

- you then proceed to put on layers of gradually thinner dilution, starting with half up to 1/8 or even 1/16 for the last few

- oil is there to ensure no friction of your pad. You add only a tiny amount to later layers, but since it is pure lineseed oil it will harden along with resin. Since concertinas are so small, it is not really needed, because you’ll still have a fresh load on your pad at the end of the current layer. You basically make one or two quick swipes and then wait for the layer to solidify for an hour or two.

 

Final coat thickness is too low to even out pores, so no, even 30 layers is not enough to ensure glossy finish without filler. 
 

If however a satin finish is the goal, it is way faster and simpler to apply shellac with flat, soft brush.

[Peter Smith]

This reminded me of a link a while back, where 'Super Nicko' burnishing cream was recommended for cleaning up old french polished surfaces.

It works a treat - like a very fine abrasive - removing dirt and leaving a highly polished surface. I use this to clean up old wooden concertina cases, which still leaves the deeper old marks but improves them dramatically.

See the link below for more information.

 

Peter

[alex_holden]

I tend to get very inconsistent results when I try to polish up to final gloss by just rubbing with a pad. Sometimes the process seems to be going OK, then I rub all the way through the finish in one spot (typically on a sharp corner), or the pad sticks to the surface and leaves a rough patch.

 

The process I have recently been using with a reasonable amount of success is:

 

1. Sand the bare wood to a high grit (at least 800).
2. Pore fill. There are different ways to do this depending on the colour of the wood and how deep the pores are. If the pores are quite shallow I sometimes just put a few thick coats of shellac on, let it harden, sand back to the wood, and repeat until the pores are all full of shellac. This takes a while but may look more attractive than filling them with some kind of opaque paste. For woods with deep pores I've tried a bunch of different things with mixed success.
3. Build up a reasonable thickness of shellac by wiping on a lot of coats (I'm using a 2lb cut IIRC) and letting it dry between coats. This will probably take several sessions over a few days. Try not to get carried away and put too many coats on in a session or the finish can get tacky and take a long time to harden up. It's important not to let any significant dirt or fibres build up in the finish because they will become more visible when you polish the surface later. I try to keep the pad and the work area as clean as possible, and if I find any dirt that got trapped in the finish from the previous session I sand it out before putting a new coat over it. The worst sort of contamination I've had was fine metal dust, e.g. brass filings, because it shows in the finish like glitter and it's really hard to get rid of it all.
4. Let it harden for a while (at least overnight, a week would probably be better). I test the hardness of the finish by pressing a fingernail lightly on an inconspicuous spot. If it doesn't leave a dent it's hard enough to polish.
5. Sand it smooth in several stages up to 1500 grit. (If you accidentally sand through to the wood anywhere, go back a couple of steps and build up more layers of finish.)
6. Polish to a gloss using Super Nicko polish.

 

I've stopped using any oil because it didn't seem to do anything useful for me, and the final finish seemed softer if there was oil in it.

[SteveS]

I add gum sandarac to my shellac to improve the hardness - it was recommended to me by a luthier acquaintance.

[SIMON GABRIELOW]

When I made a few veneered boxes ( and musical zither type instrument) I used a very tough resistant coating, that I believe was also used in commercial settings for hard-wearing worktops; horrible to put on, but so tough it has never needed recoating decades later.  It came with a separate bottle to mix in that hardened the coating.

If you are not too concerned about traditional finishes, then there are many modern alternatives, varnishes, polishes, that can be used equally as successfully these days. And could be removed if need be without harming the original surface. In the past, I have merely painted on a single layer of varnish then sanded over, to help fill in the grain, before polishing begins.

Incidentally, for standard furniture polish you can make your own by using gum turpentine, and mixing in shredded beeswax blocks. It gives a lovely mellow colour to wood and nice scent when using it too. ( Possibly not recommended for concertina wood though) as wax polish would get into instrument.. just a nice polish to make generally.

Edited February 4, 2023 by SIMON GABRIELOW
Added thought to text.

[alex_holden]

12 hours ago, SteveS said:

I add gum sandarac to my shellac to improve the hardness - it was recommended to me by a luthier acquaintance.

 

Interesting, what ratio do you use? I've also heard the suggestion to add a synthetic resin called Paraloid B-72 for the same reason. I've not experimented with either myself yet.

 

There are loads of different finish recipes in the violin and guitar worlds, and a degree of secrecy too. I was listening to a guitar maker on a podcast a while ago and he claimed to have invented an easier to apply and much more durable shellac based finish, but he wouldn't say what was in it because it was his trade secret.

[alex_holden]

12 hours ago, SIMON GABRIELOW said:

When I made a few veneered boxes ( and musical zither type instrument) I used a very tough resistant coating, that I believe was also used in commercial settings for hard-wearing worktops; horrible to put on, but so tough it has never needed recoating decades later.  It came with a separate bottle to mix in that hardened the coating.

 

Sounds like it might have been an epoxy resin finish.

 

12 hours ago, SIMON GABRIELOW said:

Incidentally, for standard furniture polish you can make your own by using gum turpentine, and mixing in shredded beeswax blocks. It gives a lovely mellow colour to wood and nice scent when using it too. ( Possibly not recommended for concertina wood though) as wax polish would get into instrument.. just a nice polish to make generally.

 

If you replace some of the beeswax (say 10-15%) with carnauba wax, it will make it harder and longer lasting.

 

See also Alfie Shine. It's the Rolls Royce of wax polishes.

[SIMON GABRIELOW]

Just a quick note to say when making wax polish using gum turpentine, and shredded wax pieces, it is NOT heated up, but used cold throughout the process.

The wax is gradually allowed to dissolve in the cold turpentine. Gum turpentine is the sort supplied for Artist paints and very pure.

[SteveS]

4 hours ago, alex_holden said:

 

Interesting, what ratio do you use? I've also heard the suggestion to add a synthetic resin called Paraloid B-72 for the same reason. I've not experimented with either myself yet.

 

My ratio of gum sandarac to shellac is around 5% by weight.

 

[SteveS]

I struggled initially with FP - everything I did, following guidance on YouTube and other sources didn't work - I concluded that although the various videos were helpful, they were missing a vital aspect to FP, maybe not revealed deliberately.  I was convinced that FP might remain a black art.

Later I found a pamphlet in a junk shop (I'm unable to find it amongst my things) published around 1905 that explained exactly how to do FP, and especially to load the rubber with a small amount of 1/16 cut shellac when polishing.  Given the small surface area of the concertina, this is particularly important so as to prevent the rubber from sticking - and I tend to use a tiny drop of refined olive oil (the variety from a pharmacy) as the lubricant for my FP.

 

Also what I found using olive oil is that the oil comes to the surface as the shellac hardens.  After maybe a month or so, the FP finish is sufficiently hard to be cleaned using a little white sprit to remove the oil, and then lightly wax polished.

 

Here is an example of finished ends with a high gloss finish.

Edited February 5, 2023 by SteveS

[DDF]

On 2/4/2023 at 6:36 PM, alex_holden said:

I tend to get very inconsistent results when I try to polish up to final gloss by just rubbing with a pad. Sometimes the process seems to be going OK, then I rub all the way through the finish in one spot (typically on a sharp corner), or the pad sticks to the surface and leaves a rough patch.

 

The process I have recently been using with a reasonable amount of success is:

 

1. Sand the bare wood to a high grit (at least 800).
2. Pore fill. There are different ways to do this depending on the colour of the wood and how deep the pores are. If the pores are quite shallow I sometimes just put a few thick coats of shellac on, let it harden, sand back to the wood, and repeat until the pores are all full of shellac. This takes a while but may look more attractive than filling them with some kind of opaque paste. For woods with deep pores I've tried a bunch of different things with mixed success.
3. Build up a reasonable thickness of shellac by wiping on a lot of coats (I'm using a 2lb cut IIRC) and letting it dry between coats. This will probably take several sessions over a few days. Try not to get carried away and put too many coats on in a session or the finish can get tacky and take a long time to harden up. It's important not to let any significant dirt or fibres build up in the finish because they will become more visible when you polish the surface later. I try to keep the pad and the work area as clean as possible, and if I find any dirt that got trapped in the finish from the previous session I sand it out before putting a new coat over it. The worst sort of contamination I've had was fine metal dust, e.g. brass filings, because it shows in the finish like glitter and it's really hard to get rid of it all.
4. Let it harden for a while (at least overnight, a week would probably be better). I test the hardness of the finish by pressing a fingernail lightly on an inconspicuous spot. If it doesn't leave a dent it's hard enough to polish.
5. Sand it smooth in several stages up to 1500 grit. (If you accidentally sand through to the wood anywhere, go back a couple of steps and build up more layers of finish.)
6. Polish to a gloss using Super Nicko polish.

 

I've stopped using any oil because it didn't seem to do anything useful for me, and the final finish seemed softer if there was oil in it.

Another way of finishing is once you've built your layers and let them cure/harden is to then do the final gloss finish.This can be done by using the same" rubber" but only charging it with meths/alcohol, this thins the shellac remaining in the rubber until you are almost removing a little of the finished surface . You'll get a very gloss finish but it it is very easy for things to go awry so a lot of care is needed.

[David Lay]

22 hours ago, SteveS said:

 

Thanks to all for your great input!

SteveS: When you say "1/16 cut", I interpret you are diluting your shellac with 16x more ethanol.  What is you starting concentration?   ...or have I missed your meaning entirely?

DDF: What is "meths/alcohol"?  I might guess you are using methanol.  My web search result showed articles about methamphetamine 😐.

[alex_holden]

1 hour ago, DDF said:

Another way of finishing is once you've built your layers and let them cure/harden is to then do the final gloss finish.This can be done by using the same" rubber" but only charging it with meths/alcohol, this thins the shellac remaining in the rubber until you are almost removing a little of the finished surface . You'll get a very gloss finish but it it is very easy for things to go awry so a lot of care is needed.

 

That's basically what I used to do, but I found it so error-prone that I now prefer to "cheat" by using Super-Nicko for the final step. It's much more forgiving and the end result is pretty much indistinguishable.

[alex_holden]

6 minutes ago, David Lay said:

Thanks to all for your great input!

SteveS: When you say "1/16 cut", I interpret you are diluting your shellac with 16x more ethanol.  What is you starting concentration?   ...or have I missed your meaning entirely?

DDF: What is "meths/alcohol"?  I might guess you are using methanol.  My web search result showed articles about methamphetamine 😐.

 

I wondered the same thing about 1/16 cut. I was guessing 1/16 lb (i.e. one ounce) per gallon?

 

Meths is short for methylated spirits, which is the British name for denatured alcohol. Our meths also usually includes purple dye (to make it more obvious that it's undrinkable), which means I prefer not to dissolve shellac in it because it can give the finish a slight purple tint. You would probably be OK using it for the final polish step because that isn't building up any more thickness.

[DDF]

I have never found the dye in meths an issue with darker woods such as mahogany and rosewood etc but if the wood is pale, satinwood,birch etc I would use de waxed bleached shellac with clear alcohol. If anyone is interested the mixture we used to use to revive dirty tired french polish was equal parts linseed oil, meths and vinegar. shaken up to emulsify and rubbed on to the old polish with clean lint free cloths or a rubber then buffed of to remove the dirt and oil.

[David Lay]

8 hours ago, alex_holden said:

 

I wondered the same thing about 1/16 cut. I was guessing 1/16 lb (i.e. one ounce) per gallon?

 

Meths is short for methylated spirits, which is the British name for denatured alcohol. Our meths also usually includes purple dye (to make it more obvious that it's undrinkable), which means I prefer not to dissolve shellac in it because it can give the finish a slight purple tint. You would probably be OK using it for the final polish step because that isn't building up any more thickness.

Interesting.  I interpret that the name methylated is derived from spiking ethanol with methanol to make it dangerous to drink.  Seems a bit mean when they could use something that makes you sick rather than blind.  As I mentioned, other denaturing agents include propanol, and I just learned, methyl-isobutyl-ketone (MIBK).  I can buy "off-road"/heating kerosene that is dyed to make it clear that the road tax was not paid in the price.  (I am sure there are cheaters who put it in their diesel trucks.). I bought 190 proof denatured ethanol labeled as hand sanitizer - no dye.

Edited February 6, 2023 by David Lay

[SteveS]

My starting concentration is 200 ml of meths and 50 grams of shellac flakes.  The final shellac cut is 1/16 from the starting concentration.

 

My final polish step is with a rubber charged with meths only - but only after the 1/16 stage has cured for a month or so, and after I've removed residual oil.  When charging the rubber I use maybe 3 drops or so of meths and keep the rubber moving otherwise it'll stick to the shellac requiring then to go back a few steps, including a possible sanding stage.

 

I tend to use blond shellac and colour it with whatever dye I require, e.g., ebony.  In some cases, e.g with rosewood, I don't colour the shellac if I want the natural hues of the wood to show through.  I've never noticed the purple dye in meths being an issue, and I've not yet had occasion to FP pale woods.

 

-------

 

Ed. drops of meths when polishing are dispensed from an eye dropper.  What I found surprising at first is just how little is needed.  This is the step no one explains in YouTube videos or anywhere else, but was clearly explained in the 1905 pamphlet I have (and I wish I could find it to share).

Edited February 7, 2023 by SteveS