An Ancient Tried and Proven Finishing Method

Having spent 40+ years in woodworking, including cabinet making, furniture designing and building and antique restoration I have discovered many different techniques in doing finishing.  My finish of choice for fine furniture and antiques is in a built up oil based finish.  This process is very time consuming, but results in a very durablefinish that last hundreds of years.

This process begins with choosing a naphthenic oil as your medium.  My favorite oils are Tung oil and Linseed oil either alone or combined.  Linseed oil is most readily available as boiled Linseed oil.  If you are looking for a faster build up this oil would be a good choice.  It gives a faster build up because the oil has already been boiled.  The downside is it is softer and not as durable as Tung Oil.

On denser hardwoods such as Maple or Birch I make a solution of 2 parts Tung oil to 1 part raw Linseed oil.  I blend these oils thoroughly then cut the solution by 1/3 with a solvent such as mineral spirits, turpentine or orange oil. For softer woods such as Poplar or Basswood I cut the aforementioned blend with ¼ solvent.

After having meticulously sanded the wood to be finished with increasingly finer grit paper and ending this process with 220 grit sand paper, I thoroughly clean the wood with vacuuming and then wiping it down with mineral spirits.  It is very important to make your finishing area as dust free as possible.

When the wood is clean and ready apply the aforementioned oil solution generously with a rag.  After all surfaces are thoroughly covered then take your hands and rub the wood vigorously until you feel the heat generated.  Let the oil stand on the wood about 1 hour then wipe off the excess oil. You will then let the finish set overnight.  After a minimum of 12 hours, then rub down the wood with 000 or 0000 steel wool and again thoroughly clean before applying more of the oil solution to the wood.  On denser woods you will apply this diluted combination of oils an average of 4 times, rubbing it down with steel wool between each coat.  On softer woods this requires 8-12 applications.  The objective is to get as deep a penetration of oil into the wood as possible and to completely seal the pores of the wood.  You will generally be able to tell when this has been accomplished, but when in doubt it is better to add more coats.

After the wood is completely sealed from the inside out it is now time to build up the finish for successive coats of oil.  Make sure you have meticulously rubbed down your last sealing coat and thoroughly cleaned it as you have previously.  At this point it is now time to cook your oils.  I prefer at this point to use only straight raw Tung oil.  Many of the products sold as Tung oil are actually diluted oil with mineral spirits.  I have found two good sources for pure Tung Oil: www.realmilkpaint.com  and Hope’s Pure Tung Oil on www.amazon.com.

It is important to heat your pure Tung oil slowly uncovered until it reaches a boil, then let it slow simmer for 20-30 minutes.  At this point let the oil cool slowly.  When it is room temperature pour it into a container with a good seal top.  This is important because exposed to air the oil will harden.

Now it is time to apply the boiled oil onto the wood evenly with a clean cloth (I like to use t-shirt material).  Let each coat sit a minimum of 24 hours, after which you rub down the coat with 0000 steel wool and as before clean between each coat.

Four such coats are adequate for most applications, but I almost always do more coats, especially for hard wear areas like table tops in which case I do 8-12 coats.

When you have reached your desired build up it is time for fine finishing to reach the desired sheen and patina.  Firstly the wood is to be rubbed thoroughly with 0000 steel wool.  It may take longer than 24 hours before starting this process.  Make sure that when you are rubbing the surfaces with steel wool that the wool does not become oily.

Secondly, the surfaces are to be vigorously rubbed down with extra fine pumice stone powder.  I spray my surfaces with a spritzer bottle containing paraffinic oil, usually found in lamp oil.  Then apply the pumice stone powder to a clean soft cloth.  For flat surfaces be sure to use a flat block to make certain you are rubbing the surfaces evenly and rub with the grain of the wood.  Be fastidiously thorough with this process.  On flat surfaces I apply the oil evenly and then salt the surface with the fine powder.

After you have accomplished this step wipe off the oily surface with a rag and then wipe again with mineral spirits and finish again with a clean dry cloth.

Thirdly the final finishing is done with Rottenstone which is super fine.  You will use the same process as with the pumice stone.

This finishing process is the most durable of any finish I know and will literally last for centuries so it is worth all the time, expense and care it takes to do this finish.  It withstands water and most chemicals.  The wood remains unaffected by scratches of daily use because it has sealed the wood from the inside out, unlike topical finishes such as polyurethane or lacquer.  You will never have to worry about condensation rings on the table top.  For table tops which are cleaned weekly it is best cleaned with window cleaner or with ammonia and water solution.  Other surfaces can be cleaned monthly with orange oil.

I went to the pains to describe this ancient finishing process for the serious woodworker or for the antique restorer, because this is an authentic process of finishing that goes back thousands of years.  For ancient folk instrument crafts people this finish or a variant thereof would have been used in the finishing of their instruments even up through the 19th century.  I have seen 300 year old violins finished with oil finishes and 40-100 year old Appalachian folk instruments done in this fashion.

All that having been said, I go further to say this is not the best finish to use on modern wooden stringed instruments.  The simple factor for not using this method is that this method so thoroughly seals and finishes the wood that it dampens its sound and sustain.