The upper limit for polymerization of urushi is within a temperature range between 20°C to 30°C and a relative humidity between 65% and 85%. In order to guarantee these conditions a damp room (urushi furo ) is used. A damp room has the advantage of temperature and humidity controlled conditions as well as being dust free and being equipped with adjustable shelves.
Urushi is almost always used in combination with other materials that need to be mixed with the lacquer, such as plant oils, color pigments, fil- ling materials, and camphor. For this kind of work a spatula (hera) is used by the lacquer artist. The spatula, which varies in width and slant, is manu- factured from cypress wood, Japanese spindle tree, or Viburnum plicatum.
Fude (round brush) are available in different models and styles depending on the bristle length, thickness, and flexibility of the brush (bristle). They serve to draw fine lines and to fill decorative areas and are mainly used in the decoration of makie (spinkled pictures). It is characteristic for fude to have a one to two millimeter long brush tip on the end of a more rounded body shape of the brush’s bristles. The rounded body part of the bristles is used as a deposit for the medium, in this case urushi, that heads to the tip and, depending on the size of the deposit, allows one to draw very long lines without interruption. The brushes are always moved from the top to the bottom, vertically.
Since 2008, it is prohibited to import or trade cat fur within the European Union. Thus, alternative brushes to the usual Japanese cat hair brushes are offered within Europe. Brushes with a metal trim are not recommended because it causes discolorations of the urushi.
Ashirai kebo is a specific brush made from horse hair from the back of the horse that is used to apply very fine gold powder.
Alternatively mawata (silk wadding) can be used. In order to sprinkle gold or to polishing, the silk wadding needs to be formed to a puff.
Another small tool for area coating with sprinkling metals are scattering pipes with different mesh sizes.