How to Harden Urushi Lacquer.
It is crucial to master this key step, which is often overlooked in all Kintsugi processes involving urushi and its hardening. The 'muro' is absolutely essential for the lacquer to harden properly.
The drying box for kintsugi helps control the drying process of repaired ceramics, ensuring precise, stable results for this traditional Japanese art of restoration. In Japan, Kintsugi artisans and lacquer craftsmen place their lacquered, moistened objects on large wooden shelves called ‘muro’ (pronounced ‘mulo’) to maintain humidity while the lacquer hardens. The ‘muro’ also serves as a dust barrier.
Urushi lacquer hardens (it doesn't dry) and becomes firm in the presence of oxygen and high humidity, at an appropriate temperature.
Urushi lacquer hardens when the enzyme laccase present in the mugi-urushi and sabi mixture absorbs oxygen from the moisture in the air, oxidizes, and polymerizes the urushiol, there by hardening the lacquer.
Post : lire WHAT IS URUSHI DERMATITIS ?
It is said that a temperature of 24 °C - 28 °C and a humidity of 70% ± are suitable for the lacquer to harden. In an environment that des not meet these conditions, the lacquer will not harden easily or may present issues such as poor coating or, for example, lacquer shrinkage due to excessive humidity.
The drying of the lacquer is a natural chemical reaction.
Typical values for Kintsugi are 70 ± % relative humidity and at least 25 °C.
An appropriate environment must be maintained for 24 hours or more, typically in a cabinet, wooden box, polystyrene box, or cardboard, called Muro, Furo, or Urushi buro.
For larger objects, whole pieces are suitable as drying spaces and are called Urushi-Muro.
Of course, the muro should be checked or designed first before any Kintsugi preparation.
Create a muro for Kintsugi / simple muro.
Another solution.
1. In a cardboard box large enough to hold a bowl, cover the bottom and sides with plastic.
Then, place a sheet of newspaper or cloth on top.
2. Moisten the newspaper (or cloth, towel) with water using a spray bottle.
3. On the damp newspaper (or cloth, towel), place a board or polystyrene to create a support.
4. Place your bowl and the humidity meter next to it. Ensure that the temperature exceeds 24 degrees and the humidity is above 70%.
Notes :
For a significant number of pieces, choose a shape that corresponds to the size and number of items to be hardened. To enhance the hardening process, I add a slight source of heat.
However, if you want to go further and work with several ceramics at different stages of hardening, I use a polystyrene box with a lid equipped with a small heat source created by a lamp (not LED) with a filament of 15W/25W depending on the season. This raises the temperature to around 27-30 °C. Additionally, for humidity, I use an appropriate bowl filled with water and a hygrometer thermometer.
In hot seasons, I turn off the lamp and regularly monitor the humidity. It’s important to adapt your muro to the seasons.
WARNING -
Typical cheap hygrometers are not very accurate.
Expect ± 10% variance in humidity readings from a cheap hygrometer. Hygrometers suitable for our Kintsugi needs with ± 5% accuracy are acceptable.
#Kintsugi # ArtJaponais #RéparationCéramique #BeautéDesImperfections #KintsugiArt
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