A few people have asked if I could give a tutorial on how I apply french polish. But before I do that - I think a little explanation of why I use french polish is in order.
Of all the finishes available to me - french polish does the least damage to the overall color and clarity of the wood. Oil is a sure fire way to darken Rosewood to oblivion and all the color and vibrance that makes rosewood so stunning is killed. Oil also kills East Indian Rosewood, turning the vibrant purple and red tones into mud. Oil does not affect Honduran Rosewood as much, but it does darken it. I do use warmed double boiled linseed oil on boxwood and then a coat of paste wax. For some reason - that finish seems a perfect “fit” for boxwood - and the darkening is not a bad thing.
French polish will wear with use - and I don’t mind that because as your hand rubs the finish, it will burnish the remaining french polish and wood to a similar luster. It is also a welcome part of the planes patina - its story if you will.
French polish is also a very pleasing tactile finish, it has a bit of a sheen to it, but not a plasticized look.
Not to mention it is a fairly safe finish.
Ok. On with the show.
I sand all the infill pieces to 600 grit. I start at 220, then 320, 400 and finish with 600 grit. A fellow planemaker once suggested the reason I use french polish was to avoid having to be particular about sanding. I just said “hmmm”. The above photo shows the inside surface of the front bun without finish applied.
Here is the kit. The white(ish) piece on the bench is foamcore which I use to test the mixture of the french polish and the mineral oil. I used foamcore because the surface is very smooth and not absorbent... and it was lying around from my design days. The shellac in the mason jar is a 2lb cut - roughly. I mix my own shellac using super blond flakes. I write the date of mixture on the top of the jar and a few months in, will add a splash of shellac thinner to compensate for evaporation. The film canister holds the rubber and the clear bottle with the white lid is drugstore mineral oil.
The rubber is made up of two pieces of cloth. The piece on the left is a 2-1/2" square of 100% cotton bedsheet (no really - it is an old bedsheet). The other piece is some other cheesecloth like fabric... but it is not cheese cloth.
I fold the cotton into thirds and then thirds again, place it along a center line of the “cheese cloth”, fold the cheese cloth down, then each side over. This is the rubber. It is flat for a reason - it lets you get into corners and is quite flexible and agile.
This is the grip I use. The section of the rubber at the tip of my thumb is held to the edge of the mason jar of shellac. I tip the jar until the shellac touches and charges the rubber. There is a small pool of mineral oil to the right of this brown spot. I touch my finger to the mineral oil and then transfer this drop to the rubber.
I place the rubber on this brown area (created over the last 8 years) and start circling it around. What I am looking for is a vapor trail. I want to see the alcohol flashing off just behind the rubber. It is kinda like the tail of a comet. When the trail is continuous as I go round and round - it is properly charged (at least for what I am using it for).
This is what a charged rubber looks like.
Very quickly, and with a fairly light touch, wipe the surface of the wood. There should be enough shellac and oil mixture to change the color of the entire surface of this front bun. You have to be quick and keep things moving - if you pause, the rubber will stick and will make a mess of things. As a point of reference - the inside of this bun should take about 10 seconds to apply a single coat.
Here is the surface after the first coat.
A few other points. I apply two coats a day - no more. This gives the shellac enough time to harden a bit and the next coat will not soften and remove too much of the previous coat. This process of softening the previous coat is what makes french polish so repairable. A little bit of the first coat is softened during the second coat and this is what allows french polish to build and fill the pores of the grain.
The flat profile of the rubber is what allows me to get into the corners on the front bun of a panel plane for example. The bun of a panel will take about 4 charges of the rubber - one for each side. After about the 6th or 7th coat, there is usually a little bit of oil on the surface of the infill so I don’t always need to put a drop of mineral oil on the rubber for the remaining coats.
Some woods like Ebony, African Blackwood and Honduran Rosewood build quite quickly because their pores are so small. East Indian rosewood take a bit more time. On average - I apply about a dozen coats to each plane.