Materials for KINTSUGI Technique
URUSHI - Japanes lacquer
URUSHI NO KI (Latin: Rhus-verniciflua or also Toxicodendron vernicifluum), a tree belonging to the family of anacardiaceae (sumac family), is the source of the natural lacquer known under its Japanese name URUSHI that is obtained in Japan, China, and Korea. After ten years of growth an URUSHI NO KI tree reaches a height between ten and fifteen meters with a trunk circumference of about half a meter, and it produces about 200 grams of lacquer.
Varieties of lacquer for KINTSUGI
KI URUSHI - Raw lacquer (SESHIME URUSHI - Branch lacquer)
Raw lacquer is required for gluing work. The standard raw lacquer is KI URUSHI, which is now often available under the trade name SESHIME URUSHI and is used for KINTSUGI.
The SESHIME URUSHI (also EDA URUSHI) is mainly used for primers and together with other natural materials such as NIKAWA (animal glue), rice paste or wheat flour.
KURO URUSHI - Black lacquer
The best known is the black Lacquer (KURO URUSHI), which impresses with its fantastic gloss and glaze-like depth effect. In early times, carbon in the form of lampblack or the finest charcoal powder was used for its production. Later, acetic acid iron oxide (iron content between 0.5% and 2%) was also added to the refined Lacquer to achieve a black color with corresponding optical effect. Lacquer that gets its color from iron oxide is also called ROIRO or KURO ROIRO URUSHI.
AKA URUSHI (SHU URUSHI) - Red lacquer
Red Lacquer (AKA URUSHI) is made by mixing cinnabar and SHUAI URUSHI (translucent lacquer) with the addition of perilla oil. The shade varies from light to dark depending on the fineness of the pigment. Today, synthetic pigments are often used for cost reasons.
SHUAI URUSHI - Translucent lacquer
Transparent lacquer or translucent lacquer, (SHUAI URUSHI) is mixed with colored lacquers (red, blue, yellow, and green) in Japanese lacquer art, as these contain a larger proportion of solids (pigment).
BENGARA URUSHI - Red-brown lacquer
Compared to the AKA URUSHI, the BENGARA URUSHI, which is also considered a red lacquer, is somewhat browner. BENGARA URUSHI is produced by adding red ocher containing iron(III) oxide to translucent lacquer.
Grain
Rice with a high starch content, as used for the preparation of SUSHI, is most suitable. It is cooked until it becomes a paste or ground into flour similarly to wheat grains and then processed accordingly. For the natural varnish technique, wheat flour has also been processed for about 500 years for priming and design compounds but also for the preparation of an adhesive with other raw materials and URUSHI.
NIKAWA - Animal glue (hide glue)
These glutin-based hot-melt glues are water-soluble and not temperature-resistant. Glutin glues can discolor on contact with metal, which also reduces the adhesive strength. Both hide glue and bone glue or a mixture of both are used together with URUSHI.
JINOKO and TONOKO - fillers
Diatomaceous earth has been mined in WAJIMA for over 500 years. Diatomaceous earth is diatomaceous earth — also known as tripel or celite, among other names — a weathering product from siliceous shells of fossil diatoms. The diatomaceous earth is purified with a great deal of work, formed into blocks and fired at about 700°C. The diatomaceous earth is then finely ground. The fired material is then finely ground to produce the mineral powder JINOKO.
The second important filler is TONOKO - a mixture of image-forming (clay and kaolin) and non-image-forming minerals. The unformable portion is about 75% and consists mainly of quartz, feldspar, and mica. Other trace elements influence the color of the clay, which ranges from white (SHIRO TONOKO) to red (AKA TONOKO). TONOKO is mined in YAMASHINA near KYOTO.
KINPUN - powder gold
Powdered gold (KINPUN, HONKIN) is processed for KINTSUGI. It is available in various grain sizes, shapes and colors, with the shade of pure gold being preferred.