Urushi Lacquer
I became very interested in urushi lacquer a few years ago after looking into alternatives to the oil-based finishes I use on my wooden tableware now. As my business grows my work is slowly being introduced to a broader market beyond that of the geeked out Green Woodworking community. My fellow geeks understand that a simple oil finish may not prevent woodenware from cracking during its characteristic movement in use, that it will have a taste, and show wear over time. Wood is fickle—cups and bowls made from it need to be used regularly. The broader market may not understand this nor like that woodenware with a simple oil finish needs very special care—and no it can’t be put in the dishwasher. Japan has a long history of using wooden bowls and cups in comparison to the West where the use of wooden tableware died out hundreds of years ago. Surviving woodenware from Japan dates back thousands of years. I have no doubt that the finish used on those wooden items significantly influenced their longevity and I wanted to learn more.
I learned a lot in my search. I found that ‘food grade’, according to the FDA means just about any finish that is completely cured and is not chipping or flaking off from use. This means epoxy, polyurethane, and many other natural and man made options. I don’t judge any of these options. Have you read the testing results for food grade epoxy that meets or exceeds the CFR Title 21, Part 175.300 relating to direct food contact? It’s impressive. I think breathing the air in most major cities might be more of a health risk than eating from something that meets the standards. Of course there are the natural standby’s that meet the same standards like food grade linseed, tung (china nut) or walnut oils. I’ve been using these oils for years and with it comes the endless discussions about allergies from nuts and in particular walnut oil (extremely unlikely) as well as navigating customers’ dislike of the strong taste or scent of these hardening oils. Not to mention the impossible curing times of months if at all (for the oil inside the wood).
This brings me to Urushi. It’s been used for over 8000 years in the Far East for all kinds of applications including coating woodenware. 8,000 years is a really long time. It’s just a guess, but its use is likely to predate any of the aforementioned natural pressed oils.
So what is it?
It’s the sap from a tree. It’s that simple. But there is a caveat. This tree, Toxicodendron vernicifluum, and its sap contains the compound urushiol. This compound, urushiol, is also in poison oak and poison ivy among a few other plants. It’s the urushiol that’s the key. When exposed to high humidity an enzyme is activated and extracts oxygen from the water and supplies it to the urushiol. The urushiol solidifies or polymerizes, forming a hard film. Even after it’s hardened, the urushi retains some of the original water, making it look perpetually wet and shiny. Fully hardened Urushi lacquer is very stable and strong. It is able to withstand alkali, acid, and alcohol, and also being able to resist temperatures of over 300 C - 570 F. It is also resistant to molds and mildews. It does have weaknesses…it can be degraded by UV rays from the sun and other sources or extremely dry conditions. The draw back for such a perfect natural finish is that contact with the uncured sap creates contact dermatitis. Most of us have had or seen a reaction at one time or another from contact with poison ivy or oak. You can do a quick internet search for some brutal images. There are a few among us that are immune to the effects so count yourself lucky if you fall into that group. I used to get poison ivy pretty bad when I was a kid. Once fully and properly cured, reactions are very rare. But curing needs to happen in very specific humid and warm conditions. Without the ideal conditions it may not cure or only partially—thus exposing anyone to the potential for a serious rash. Here is information that is commonly included when purchasing lacquered goods in Japan.
One of my bowls finished with urushi lacquer.
The quality of the finish stands on it own and it’s easy to see just how special this lacquer is. In fact, after Europeans were introduced to it they tried to copy it using a variety of ingredients and processes. The term ‘Japanning’ basically refers to the imitation of Asian urushi lacquer. I wish there was a book on this history in English. It would be fascinating.
Urushi lacquering is a specialized trade in Japan with a lot of regional differences and techniques too numerous to list here. Many of them require years of training to become proficient and all of them require constant exposure to the raw lacquer. Most of these techniques require many thin layers of lacquer to be applied over many days. Each layer needs to harden first before applying the next coat. Depending on the humidity and temperatures 20 layers could take months to apply. There are also many types of lacquer, some for the base coat, some for the middle coats and some for the top coats. There is very little information on these processes or the types of lacquer in English.
I decided I would look further into urushi when I taught and traveled in Japan last spring. I talked to many different craftspeople about urushi. They all expressed with a nod and smile by saying “urushi” as they simulated scratching their arms or wrists. I had arranged a short lesson which consisted of coating a bowl I made and Jazmin coated a spoon she had carved. We learned enough to feel confident that we could continue to learn back at home in the US.
Lacquered woodenware is very common in Japan. Most everyone knows it. In fact you can find it in department stores sitting alone aside plastic bowls. It’s a weird sight, but true. We returned with a few bowls and cups and we’ve been using them at least once a week if not more. The more they are used the more rich the finish gets. Slowly it becomes more transparent revealing a layer of colored lacquer underneath the top layers. It’s really amazing.
Two renge spoons that I made with urushi finish are in our Japan Fundraiser shop.
I take learning about urushi very seriously. This is because Urushi is viewed by some as deeply connected to Japanese culture. I started using it with very little background to its significance or without in-depth training. This leads to a much bigger question about craft, craft skills and their ties to culture. These big questions are also strengthened by the requests to post a how-to video on youtube, like it is something you can master by watching a video or more recently reading someone’s Instagram post about their experiments with urushi and actually stating falsehoods about its potential skin reactions or describing a very haphazard way of attempting to cure it. These situations really get me thinking. While discussing and reflecting to Jazmin she interrupted sarcastically “So what are people to do, go to Japan and learn?” I thought about it for a minute and then replied with a firm yes. This is how to respect urushi. It is a skill that absolutely requires some training. Anyone wanting to work with it should have at least some training and basic understanding of how to properly cure it. It’s really that simple. In this day and age the idea of having to have some special training I’m sure will be viewed as elitist. But I really don’t care. The risk of giving someone a reaction is not worth it to me. This is in part why I’m writing this post. It is also why I don’t post a lot of photos about my experiences with urushi as I learn to use it. This includes countless reactions on my hands, arms, etc…and accidental ingestion of partially cured lacquer because I was careless and didn’t understand the importance of proper curing. So yeah, it deserves the utmost respect.
But I digress.
The method I was shown was called fuki urushi. It uses a type of urushi lacquer called seshime which is dark brown in color. After wiping the wood with a dust free cloth you brush on a thin coat of seshime then wipe it off. We use a special type of cloth for this that doesn’t leave it’s fibers behind like a paper towel would. We then put the freshly lacquered object in a muro. This is a wooden cabinet that has been set up so that the humidity and temperature can be controlled. Japan is a humid place, especially in summer, so curing is easier there. Once you understand this it becomes easier to understand just how the finish was first developed all those years ago. Did I mention that was 8000 years ago?! I’ve heard stories that during the summertime lacquer artists try to take advantage of the ideal conditions for curing and plan on getting a lot of work done. In our muro we use humidity and heat controllers that are marketed for folks that have pet reptiles. Once in the muro we leave the coated object for at least three days with very strict climate control of 75-85% humidity and temperature of 70-80F. I like to put on 3-5 coats, so to complete the process can take weeks.
I’m not sure what you believe in, but I can say that urushi has a presence. As soon as I walk into the room I feel it. Glancing over in the direction of my dedicated work area is like reacting to the sense that someone is watching me. The tubes of lacquer are there, quietly resting. Working with it takes dedication. It’s inevitable that after you begin to use it you will react—even while wearing gloves and trying to be very careful. I’ve recently gotten over a few reactions on my fingers and upper underarm (I’m not sure how it got there). I’ve also had more serious reactions that covered my whole forearm this past summer. Because the reaction from urushiol is an allergic response, the body can be trained through exposure and mental attitude to not react. I’m slowly building up an immunity to it. This could take years—especially if exposure is infrequent. Because of this I try to use it every few days.
This Spring we will travel back to Japan were we have more extensive lessons planned. This will continue my training and is very exciting. Traveling to Japan is not cheap so we thought that we would offer a few lacquered or painted bowls, cups, and spoons as a way to raise some money for our trip. These objects will be made after we return from our trip in April and after more extensive training. If you are interested the fundraiser is here.
I believe that our work with urushi is important. Here in the US or in the West urushi is pretty much unheard of. My hope is that its use may help to increase the use of woodenware. But I need to say again that it is not something to ‘play’ around with. I’m beginning to accept that working with it takes dedication and respect. In fact it demands it.