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 20 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 necessary for gluing projects. The standard lacquer usually used for those projects is ki urushi which in Japan is also used for kint- sugi. One can find that ki urushi is available under its trade name Seshime Urushi.
In former times the neatly cut tree branches were immersed in water during the winter in order to win seshime urushi – the branch lacquer – or also known as eda urushi. Seshime urushi is mainly used for base coating and glue lacquer which can be used in combination with other natural glues such as nikawa (animal glue).

ki urushi - Rohlack

kuro urushi - Black lacquer

The best-known lacquer is the black lacquer (kuro urushi) that impresses by its fantastic gloss and its glaze-like depth. In the past, carbon in the form of lamp soot or fine charcoal dust has been used for its manufacturing. Later, acetic iron oxide (iron content between 0.5 % and 2 %) was added to the refined lacquer in order to achieve a blackening with a certain optical effect. A lacquer that obtained its color from iron oxide is also referred to as roiro urushi or kuro roiro urushi.

kuro urushi - Schwarzlack

aka urushi (shu urushi) - Red lacquer

By mixing cinnabar, suki hakushita urushi (translucent lacquer), and Perilla oil, red lacquer (aka urushi) is produced that is also called shu urushi. The shade of color varies according to the fineness of the pigments from light to dark.

aka urushi (shu urushi) - Rotlack

syuai urushi - Translucent lacquer

Transparent varnish - translucent varnish - (Syuai urushi)
In the Japanese lacquer technique, the translucent lacquer is mixed with the colored Urushi red, blue, yellow and green, as these contain a larger proportion of solids (pigment).

aka urushi (shu urushi) - Rotlack

bengara urushi - Red-brown lacquer

Compared to the shu urushi, the bengara urushi, which is also considered to be red lacquer, is a bit browner. Bengara urushi is made by adding iron(III) oxide (iron oxide red, Indian red) to translucent lacquer.

bengara urushi - Rotlack

Grain

High-starch rice, such as that used for making sushi, works best. It is boiled until a porridge is formed or ground into flour similar to wheat grains and then further processed accordingly. For the natural paint technique, wheat flour has also been processed for about 500 years as an adhesive thickener for primer and design masses, but also as an adhesive with other raw materials and urushi.

Reismehl

nikawa - Animal glue (hide glue)

These gluten-based hot glues are water soluble and not temperature resistant. Glutin glues can discolour on contact with metal, which also reduces the adhesive strength. Hide glue is more elastic than bone glue and is therefore more suitable for kintsugi.

nikawa - Tierleim (Hautleim)

jinoko and tonoko - fillerstoffe

Diatomaceous earth (jinoko) has been mined in Wajima for over 500 years. Diatomaceous earth is diatomaceous earth - also known as tripel or celite - a weathering product of silica-containing shells of fossil diatoms. The diatomaceous earth is fired at approx. 700 °C and then ground.

The second filler is tonoko - a mixture of malleable (clay and kaolin) and non-ductile minerals. The inductive portion is around 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.

jinoko - Diatomenerdetonoko - Tonpulver

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.

kinpun - Pudergold