What is a French Polish technique on a lathe?

[Brian Kent]

I have tried a whole lot of finishes on lathe work. But I am not sure what it would mean to do a French Polish on a lathe. Could someone point me to a process or describe the materials?

Thanks

[Steve Schlumpf]

Brian, the term French Polish loosely means applying multiple thin coats of finish in order to achieve a high gloss. The key to success is to use very thin coats and allow to dry before applying more. By being very thin, drying time is greatly reduced and depending on temperature and humidity, you can often get multiple coats applied in a days time. I do this (off lathe) on all my WOP finishes.

[Brian Kent]

Well then I do that with several kinds of wipe-on finishes. Dewaxed shellac, WTF, WOP, leveled when needed.

[Doug Herzberg]

Brian, my understanding is that French polish refers to a blend of 1/3 shellac, 1/3 BLO, and 1/3 DNA. It is applied on the lathe with a cloth in several thin layers. The idea is that the BLO acts as a lubricant, allowing you to bring the shellac to a high polish before it gets too sticky. Some turners use the method because it allows them to finish a project quickly while on the lathe and move on to the next job.

[Brian Kent]

Good, Doug. I'll try that combination.

[Frank Drew]

In most traditional versions of the French polish method, the oil is only used as a lubricant to the pad which is actually apply the shellac finish. The pad is usually balled up cotton or wool wrapped inside a piece of fine-weave linen, or sometimes cotton.

[Allan Speers]

Brian, my understanding is that French polish refers to a blend of 1/3 shellac, 1/3 BLO, and 1/3 DNA. It is applied on the lathe with a cloth in several thin layers. The idea is that the BLO acts as a lubricant, allowing you to bring the shellac to a high polish before it gets too sticky. Some turners use the method because it allows them to finish a project quickly while on the lathe and move on to the next job.


Technically, french polish is a technique, not a formula. The really important part of the process is using a lubricant, like mineral oil, and an abrasive material like pumice, which sort of "sands" the top layer of the wood and creates a slurry that fills the pores. You can do it without the pumice, but then it takes much longer.

However, some species with tight, closed grain, like Maple, don't need the abrasive.

[Michael Mills]

I agree with Doug and Frank. I used a premixed/premade which was Qualasole for flat items (jewelry boxes).

Mylands friction polish is basically the same thing.
On the lathe (with an item maybe 8" long) you apply the Mylands a couple of drops at the time to the pad. By the time you reach the end (maybe 10 seconds) the other end is dry and ready for the next coat. When I have used it I can apply 20 coats in no more than 30 minutes with time to add new polish. I use standard shellac first and burnish with 4-0 steel wool before the Mylands; if not it may take forever to fill any pores or voids.
Make sure the cloth is wrinkle free or it will build up in the wrinkle area and leave rings on the piece.
I have never used it on anything over 3" diameter. I'm not sure it can be used on a bowl because it dries so quickly.

[Steve Huffman]

Brian, my understanding is that French polish refers to a blend of 1/3 shellac, 1/3 BLO, and 1/3 DNA. It is applied on the lathe with a cloth in several thin layers. The idea is that the BLO acts as a lubricant, allowing you to bring the shellac to a high polish before it gets too sticky. Some turners use the method because it allows them to finish a project quickly while on the lathe and move on to the next job.

I just used this method for the first time as Doug has mentioned here on a small pet urn. I got this Brian from the "Capt. Eddie" video on youtube, and I was looking for something other than the glassy look of sprayed lacquer, more like polished wood look, or more satin appearance. I didn't get the best results I had hoped for, and I have the feeling my shellac is old too if that makes a difference. I ended up with a couple coats of tung oil finish, (not the pure oil) and a couple coats did the job. Polished it up with Ren wax and got just right amount of sheen. I hope to post this urn soon....other work is killing my turning time.

[Doug Ladendorf]

Fine Woodworking had an excellent article on French polish a couple years back. If you subscribe to the online site you can access.

[Prashun Patel]

I am unfamiliar with the mix Doug references.

French polishing that I've read about and tried involves 1) padding on shellac in the 1#-2# cut range, possibly lubricated with a drop or two of mineral oil, then 2) 'spiriting off' the finish by padding on DNA to remove the mineral oil and to move the shellac around to a thin, perfect finish. It can also involve some grain filling.

IMHO, a modified French polish technique on the lathe is extremely easy. It's the way I apply shellac on turned vessels (unless I'm hvlp-ing). You just pad on thinned shellac with the lathe on. You do one pass from the foot to the rim, and keep the lathe on for a minute. Then let the shellac fully dry, and do another coat. You do this a couple times, then do the same with a pure DNA pad.

(edit): the one caveat I'll offer is that if the lathe speed is high, the shellac heats up under the friction of the pad, which can prevent a perfect shine. You have to use a light touch, low speed, and don't linger.

[Jon Nuckles]

As others have said, a true french polish involves very little oil -- just enough to keep the pad from sticking as you apply the shellac. After you get the shellac on, you then spirit off the oil with alcohol (dna unless you are concerned about denaturing chemicals and are willing to pay the taxes on pure grain alcohol). The idea is to apply a very thin but absolutely smooth surface. The pores should be filled prior to or as part of the process. As you polish, you will go over the section you are working on dozens or perhaps hundreds of times during a single finishing session. That is why it is so labor intensive when doing flat work, and it is more art than science in knowing how much pressure to apply, how much shellac to add to your pad, when to add a drop or two of oil, and when to stop and let the finish rest.
A french polish is much easier on the lathe because you only have to do a little of the work of moving the pad across the piece. While you can "body up" by applying shellac more heavily at first, the real polishing is more about moving around the shellac that is already applied than it is about adding more. If you are looking for a high gloss finish without the plastic look that poly can leave, a french polish can't be beat. If you want anything less than high-gloss, a french polish is not for you.
Keep in mind that shellac can always be dissolved by alcohol, so use coasters if you put your scotch on a french polished table top. You can also use a "padding lacquer," which is a shellac with a mix of solvents formulated to give an evaporation rate that is ideal for the padding process. Mohawk sells a couple of them that are mostly marketed for repairing finishes in the field. One has a higher shellac ratio and gives a faster build than the other. Both are very thin compared to a typical shellac cut, however, so I recommend applying some shellac first and then using the padding lacquers to get the final finish. On the lathe, you probably don't need a padding lacquer, so you can save yourself from their fumes and expense.

[Geoff Whaling]

Brian not sure if you get "Ubeaut Shellawax Glow" in the US but it will create a fine lusterous finish similar to french polishing. I have heard of a similar product available as "Dr Kirks" I think?

[Brian Kent]

For French Polish is Isopropyl Alcohol the same as denatured alcohol? I mean can I use Isopropyl Alcohol?

[Prashun Patel]

Denatured alcohol is typically ethanol. It is to isopropyl alc what naphtha is to mineral spirits. They are largely interchangeable. Ipa will slow the drying of the shellac marginally vs ethanol.

Dont use rubbing alcohol tho.

[Brian Kent]

I already had a number of dewaxed shellac layers. Yesterday I spent a lot of time applying more dewaxed shellac with denatured alcohol and a bit of mineral oil mixed together. The lathe was on the minimum speed of 250 rpm.
This morning I used the alcohol to take off the oil and move the shellac. The lathe was off and I moved in long circles mainly bottom to top to smooth out the rings.

I can see that it is not done. Still dull at the base. A dull area near the rim, and a little bit left of the circles.
I can repeat the process, either using mineral oil or blo in the mix.
Will I do this many times? Will it be glossy when I am done or will I need to Beall-buff after it hardens?

Thank you all for your help.

[Mark Greenbaum]

The french polish technique I subscribe to was from a guitar building forum, and the demonstrator used super blonde flake shellac dissolved in DNA or PGA, and applied liberal coats with dauber made of lint-free cotton with cotton balls inside. The coats melt in the previous layer, and the final coats are lubricated with drops of olive oil. I have hand applied and applied while on the lathe at low speeds, and gotten a nice luster that is natural, and water-repellant, as well as easy to maintain.315695 The mentors at the club said it's not a durable finish for a salad bowl, but we wash it in dish soap and wipe off fine. I have not had to repair it yet, and that's 4 years now.

Here's that video link: http://www.finewoodworking.com/how-to/video/how-to-create-a-sunburst-finish.aspx (http://www.taunton.com/finewoodworking/SkillsAndTechniques/SkillsAndTechniquesArticle.aspx?id=30182)

[Allan Speers]

The french polish technique I subscribe to was from a guitar building forum, and the demonstrator used super blonde flake shellac dissolved in DNA or PGA, and applied liberal coats with dauber made of lint-free cotton with cotton balls inside. The coats melt in the previous layer, and the final coats are lubricated with drops of olive oil. ....

Mark, are you sure he didn't have pumice inside that dauber? (often referred to as a "tampon" BTW) I used to build classical guitars, and that was the standard way to french polish. It would be a royal PITA without it.

[Mark Greenbaum]

Mark, are you sure he didn't have pumice inside that dauber? (often referred to as a "tampon" BTW) I used to build classical guitars, and that was the standard way to french polish. It would be a royal PITA without it.
Nope, no pumice. I don't own any pumice (except a 5 lb chunk I picked in Oregon). I did sand while still on the lathe, and burnished it with shavings. The first coat was a flood coat, and let it sink in and seal the wood. This bowl is spalted silver maple. Then 0000 steel wooled. Also steel wooled after every 3rd additional coat (I applied about 12 coats), then good old fashioned elbow grease and final coats with olive oil lube. After it settled in, I did put a coat of Johnson's paste wax (because I love the smell of that stuff - reminds me of when I was a kid, and Mom would wipe off the furniture with it). Then I lightly rinsed it with warm water and a towel to dry it off.

[Jon Nuckles]

Brian --
Because the alcohol will dissolve the shellac as you are spiriting off the oil, it is very important to keep the rubber moving and control the pressure or you can easily spoil the finish you have achieved. I have also found that using too much oil when applying the shellac can make the finish soft and impossible to rub out to a high gloss. I would try to do the last step with the lathe on. If the finish is soft, however, my only success in getting a good finish is by removing the finish (with liberal doses of alcohol) and starting fresh.

Allan --
I have used pumice to fill the pores, but not beyond that point in the process. Do you use pumice throughout the process?

[Allan Speers]

Thanks, Mark.


I think the fact that you didn't use pumice is why it took 12 coats. When I built guitars, the spruce tops used to take maybe three short sessions, because the pumice creates a swarth that fills-in the pores. You don't see it when finished, so for me this is a no-brainer, but obviously there are other workable methods. I did a few maple bodies, and they didn't require pumice, as the pores fill much faster than spruce & rosewood.

[Allan Speers]

Allan --
I have used pumice to fill the pores, but not beyond that point in the process. Do you use pumice throughout the process?

Not the last coat. - but again, this is a guitar-finishing thing. (Extremely standard with luthiers.) I don't profess to know what's best for all furniture & all species of wood. In fact, I'm finding this thread fascinating.

[Doug Herzberg]

Not the last coat. - but again, this is a guitar-finishing thing. (Extremely standard with luthiers.) I don't profess to know what's best for all furniture & all species of wood. In fact, I'm finding this thread fascinating.

I'm learning a lot, too, Allan.

Brian, I don't use this method often. When I did, I was usually turning green to finish and wanted something that would be done when I took it off the lathe. I fiddled with the finish until I was satisfied, often taking everything off with DNA and starting over, but when I was done, I was done. The whole point for me was to have a finish I didn't have to keep coming back to. I was able to get some satisfactory results, but it takes a little practice.

[Mark Greenbaum]

Allan:

I did not use pumice because I don't think that video was geared towards the filling of the wood pores, as much as learning to do the dyeing and bursts then covering with a French Polish. The silver maple was sealed after the first coat. And I had a good lustrous shine at about 4 coats; I just wanted more for the durability. Recently a demonstrator at our club show how to seal with 50/50 Helms Sparathane and mineral spirits with lathe spinning about 50 rpm. He sanded lightly with about 280 grit, and wiped, and applied more coats of full strength Helms Sparathane, a coat every 20 minutes. Great finishes with minimum work.


Thanks, Mark.


I think the fact that you didn't use pumice is why it took 12 coats. When I built guitars, the spruce tops used to take maybe three short sessions, because the pumice creates a swarth that fills-in the pores. You don't see it when finished, so for me this is a no-brainer, but obviously there are other workable methods. I did a few maple bodies, and they didn't require pumice, as the pores fill much faster than spruce & rosewood.