Kintsugi Techniques: A Detailed Look at the Art of Repair
This bowl shows the telltale golden veins of a repair by the ancient Japanese technique of kintsugi.
There is a boom going on in the Japanese art of repair called kintsugi. A quick search on the Internet will turn up links to several major exhibitions in the last couple years. This ancient, traditional art is starting some well-deserved attention outside of Japan.
As I’ve noted in a previous article, if you are interested in an ecologically sound way to repair treasured items kintsugi is a great alternative.
There are many ways to approach the basics of kintsugi. The foundation of the ecologically sound repair method is lacquer. Real lacquer. The fact that lacquer is such a difficult material to work with and that it causes a rash has kept the methods on how to use it shrouded in mystery.
Lacquer is a very strong adhesive, and its adhesive strength lasts many hundreds of years. Lacquer used on its own to repair a piece isn’t enough. A broken piece of ceramic usually has missing bits that need to be filled in. There may be problems with the way the piece fits back together or the alignment.
Kintsugi starts with a test fitting of all the broken pieces to ensure they fit properly without gaps.
Using lacquer that has been mixed with a medium can compensate these imperfections. The medium gives it bulk and added strength.
Commonly used mediums include a powder called tonoko, a specialized type of wheat flour and rice. Rice is the most traditional medium, relatively inexpensive and readily available. Tonoko is also readily available but more expensive than rice. Flour is common, but the type that is recommended for use as a medium is much less common.
This tonoko powder is ready to be mixed with lacquer.
After coating with the medium, the pieces are fitted together before cleaning.
Each of these mediums produces a different type of finish. Rice is fast drying and produces a hard finish. Tonoko is slower drying and makes a rougher finish. Flour takes a long time to dry—about two weeks—and produces a strong finish but is more difficult to work with when it is wet.
The basic steps for putting a piece back together with kintsugi are the same, regardless of which medium you decide to use. First, all the shards of the piece to be repaired are gathered. A trial fitting is done to make sure there aren’t any missing pieces. The medium is then mixed and applied to the edges of the piece. After all edges have been coated, the piece is fitted back together to its original state.
The seam after it has dried and cured.
Unlike glue, lacquer doesn’t immediately form a bond. It takes a minimum of two days, though usually about two weeks, to cure enough to be handled.
The curing process is not a simple question of setting the piece aside and letting it dry. Lacquer will only cure in an environment of 80 percent humidity and more than 28 degrees Celsius (82 degrees Fahrenheit). There are special curing boxes that are used to dry it.
After the lacquer has cured sufficiently, the piece is taken out of the drying box and the cleaning begins. All the excess lacquer must be removed and the seams smoothed. This takes from one day to several weeks, depending on the amount of excess lacquer and the surface of the piece being repaired. The rougher the surface of the piece, the more difficult it is to clean.
A thin bead of lacquer is applied to the seam and metal powder is dusted to the surface.
The next step in the process is the heart of kintsugi. A thin bead of lacquer is carefully applied along the seams and gold dust is sprinkled on. Sufficient time is allowed for the gold to bind with the lacquer and then the surface is polished with a cotton-type material.
Without the polishing, the surface wouldn’t be smooth. There are some additional steps that involve polishing the gold with a fine grit paste to a smoother finish.
There are also many variations of the basic steps I’ve laid out. Some people use gold foil, some use powder. The basics are the same if it is traditional kintsugi. Lacquer followed by gold. In some variations, gold is used more as a decorative element with images of birds and leaves rendered in gold.
After polishing and cleaning, the final seam shines above the porcelain.
Some of the kits sold on the Internet and labeled kintsugi are just tubes of glue and a gold-colored powder, similar to powder sold for children’s craft projects. The materials for real, traditional kintsugi are expensive. Using lacquer is a time-intensive process and the raw material, the sap from the lacquer tree, is not easily gathered.
To get the finest lines it is important to use specially made brushes. The cotton-like material used for buffing the gold is a byproduct of silk manufacturing and is difficult to acquire. The gold is a specially ground, pure powder that is the single most expensive material for doing kintsugi.
There have been some new types of lacquer developed that are less allergenic than usual. Synthetic lacquer has also come into use. Alternatives to gold are also available. Gold powder is about $150 a gram in its ground form, and silver runs about $20 a gram. There are now powders of ground brass that are about 30 cents per gram, and aluminum sells for about the same price.
David Pike is a Worthologist who specializes in items from Japan, including porcelain.
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