Rob's April 2017 Tip: My two Favorite and Only, Finishes
My Two Favorite Finishes (Part 1)
In the era of artisan cabinetmakers, the finishing process was done by a professional finisher - not the cabinetmaker. Developing the skills to both build and finish fine furniture was beyond what these craftsmen thought was practical, 
therefore the craftsman specialized into guilds of cabinet makers, jointers, finishers, and others. All apprenticing and learning the skills of their chosen profession. I can imagine the fine furniture maker getting particularly fussy about who topped off his work. Finding a good one would be a major coo!
Fast forward to 2018 and we find weekend hobbyist trying to do what the artisans would not – master two complicated and different skills. Trying to use multiple finishing methods will most likely leave the average among us mediocre at best. I think a smarter plan is to practice with one or two easy finishes and bring that process up to par with your building skills.
I have ruined and have seen others ruin beautiful woodwork with a lousy finish. I learned my lesson the hard way. The night before a big furniture show in Halifax, Nova Scotia, I decided to try a new water-based lacquer on a key piece of work - what a disaster! The rough finish dried to the hardness of glass and could not be removed.
Since then I have stuck to just two easy to use finishes: a spray-on lacquer and a rub-on oil.
I use just one brand of lacquer and just one brand of oil. In 30 years of use I have gotten to know both very well and now I can accurately predict how they will respond under various temperatures, humidity conditions, and on different woods. I consider this skill/knowledge to be pivotal to my success in furniture making. 100 hours of careful craftsmanship can be destroyed in minutes with bad finishing. The opposite is to have great craftsmanship further elevated with a well applied finish - talk about making your day!
For my rub-on finish I use tung oil. Tung oil is extracted from the nut of the Tung tree, which grows primarily in China, Argentina, Paraguay, and parts of Africa. Tung oil has been around for thousands of years. The first record of Tung Oil appears in the writings of Confucius dated about 400 BC. Even then, the Chinese recognized the amazing qualities of Tung Oil. Throughout their history, the Chinese have used tung oil to waterproof the masts and sails of junks (boats), to finish furniture of royal families.
The brand I prefer is Circa 1850 tung oil. But you must be careful when purchasing tung oil. If you don’t read the ingredients on container you may end up with a product that while it has “tung oil” in its label it contains solvents and/or metal compounds that speed up polymerization (hardening), and/or other mystery ingredients. Sometimes the actual percentage of tung oil in these products is very low. It’s also possible to buy tung oil that has undergone a heat treatment to partially polymerize it, making it harden faster. I’m not criticizing any of these products, just informing you that buying tung oil can be confusing. If you want to read a great explanation de-mystifying all this I recommend Bob Flexnar’s Wood Finishing 101.
Tung oil penetrates deep into the wood and can give a depth to the surface unavailable from other top coats. On the downside It takes multiple coats to achieve a nice luster and requires a day between coatings to completely dry (technically it hardens). In an active and crowded shop having big furniture pieces hanging around drying can be an accident waiting to happen. Additionally, depending on the type of wood you are applying the oil to, the wood my “bleed” out some of the tung oil and bleeding can occur even hours after you think you have wiped everything dry. Close porous woods like maple and cherry tend not to bleed after wiping compared to woods like Walnut and ash that must be wiped often during the few hours after applying the oil because of bleeding.
Additionally, oil is not the most protective finish, but applying 6 or 7 coats will make a huge difference over the two coat "quick and dirty" finish routine I have seen more than once. Oil will also highlight surface imperfections that a top coat wouldn't. Dovetails that aren't perfectly tight will show when oil penetrates the end grain and magnifies that previously not so noticeable gap. Any torn grain will jump off the surface screaming "LOOK AT ME"! The penetrating characteristic of oil must be well managed. Surface finish has to be even throughout the piece to prevent color variations caused by varying absorption rates.
All that said, my Circa 1850 tung oil seems to be just right for my atmospheric conditions. I can keep a fairly large piece of furniture wet for the 15 minutes it might take to absorb sufficiently. This means keeping the surface wet with a brush and not having the starting area get tacky before you can get back to it. And I love the look obtained from an oiled, hand planed surface, it is completely different from an oiled, sanded surface, in the same wood. Cherry is a great example of this, the oil planed surface has a depth that makes it appear you can look into the wood and the oil sanded surface is like laying a piece of frosted glass over the same wood.
In terms of living with an oil finish you will have to be careful with any liquid spills, oil finishes have no place in kitchens but anywhere else they do what top coats can't-add depth! Final note on living with oil is on touch ups, oiling a scratch will only highlight it as the broken fibers absorb extra oil in the exposed end grain and darken down in contrast to the surrounding wood. However, refreshing a tired or faded surface is simple and can be done in the house with a drop cloth protecting the floor.
This reminds me of one of my earliest business horror stories. I had just delivered my biggest commission to date, a cherry dining table and 8 chairs of my own design. Custom made to go in a large new mansion, I was nervous as a cat and stupid enough to apply "one more coat" of oil on the table top in the customer’s house. While they watched, I carefully wiped the oil on with a soft cotton cloth, drop cloth in place to protect the brand-new floor in the brand-new mansion! As I carefully approached the edge of the table with the oil-soaked rag a little string of the cloth got whipped around and flung three huge drops of oil onto the custom drapes that had just been hung. I'll never forget that pit in the stomach feeling as I felt the weight of their combined stare! I am so glad I no longer do custom work!
Good luck with your oil finishes, Next month, in Part 2, I will cover my favorite spray-on lacquer finish!