Tuesday, May 12, 2009

French Polish

Some time ago I made a business decision that I think many more furniture makers should consider; to become friendlier to ourselves and to the environment.

One of the greatest leaps forward in this department is considering what material gets used as a finish on the furniture.

I used to use a pre-catalyzed lacquer that went on smooth and looked reasonably good (about as good as any mass produced furniture with a sprayed finish) however the ease in application was overshadowed by the dangers in using highly explosive, highly toxic material with a huge amount of VOC’s that off gas even months after the furniture is completed and delivered to the client.

I started searching for a finish to replace lacquer in my shop. It had to fill two major rolls;

- It had to be non (or nearly non) toxic

- It had to look great

I decided to adopt shellac as a finish, and not just ordinary shellac, but shellac applied with a technique called ‘French Polishing’.

This is the undisputed king of finishes, and has been for several centuries.

There are countless texts describing the various ways to apply a good French polish finish, but one thing that is true of all of them is the ingredients; Shellac flakes, Alcohol, and Oil

The shellac can be purchased easily at most well equipped finish suppliers, the oil, (olive, or in this case mineral oil) can be purchased at the local pharmacy, but the alcohol is a different story.

Because in Canada alcohol is heavily taxed, manufactures of grain alcohol must add a toxic element to the alcohol to sell it as non-potable alcohol, thus eliminating the need to pay taxes on it, and eliminating the possibility of people consuming it.

The most common form of toxin added in Canada is Methanol, which if ingested causes blindness and potentially death. It also has a nasty habit of migrating through protective gloved and passing through the skin, making it difficult to handle. One other nasty habit of it is that it also passes right through gas masks and gets absorbed by the body through the lungs.

I set out to find a product that was denatured with chemicals other than methanol, and I did find it after some serious searching.

So finally, on with the finish...

The one point that defers between the Italian, English and North American techniques of French polishing, and the TRUE French polish is that only in the true French polish is oil applied to the bare wood before any shellac.

I start by using a cheese cloth and liberally apply mineral oil the surfaces to be finished.

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I then wipe the surface immediately with paper towel to remove any oil not absorbed by the wood.

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I then take the ‘pad’ and add some 2lb. Cut shellac and some alcohol and begin by rubbing the pad in small circular motions all over the surface. Once the pad begins to dry out I add more shellac and more alcohol (always more alcohol than shellac)

When the rubber begins to drag on the surface I place a drop of mineral oil on the surface and use it to lubricate the pad.

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All the while I am adding just a light dusting of pumice (4F grade) to cut the finish and shine the surface.

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I keep this technique going for at least two days, and when I think the shellac is built up enough I slowly start to reduce the amount of shellac I use when recharging the rubber.

I also begin to scale back on the pumice and eventually I switch to a new pad with no pumice on it, and begin to use rottenstone.

For the final polish I use the tiniest drop of alcohol and polish the surface to a very high gloss finish using up every last bit of alcohol in the pad while at the same time removing every last trace of mineral oil.

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If all goes as planned I'm left with a very high gloss flawless finish.

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Now if I don’t want to have a super high-gloss finish on the furniture, I will rub out the gloss with 0000 steel wool impregnated with 4F pumice to leave a pleasing satin finish.