How lacquer is made

True lacquer is tree sap that hardens into glossy armor in warm, damp air.

stations: 8
things upstream: 19
raw sources: 8
steps from the ground: 5

The short version

Asian lacquer starts as sap scraped from cuts in the bark of Toxicodendron vernicifluum, in Japan about 180 grams from a tree that took 10 years to grow. Refiners strain out wood particles, whip the sap smooth, then stir and heat it to drive off water. Coats harden in a humid cabinet. Modern lacquers instead dry as a solvent evaporates.

Score the bark

Harvesters slice several horizontal grooves into the bark, then gather the sap the tree pushes out to heal them. In Japan a tree gives about 180 grams and is harvested only once. The sap contains urushiol, a skin allergen until cured.

about 180 grams per tree
Strain out the wood

Wood particles are removed from the collected sap. Now called kiurushi, or raw lacquer, it can already serve as a base coat on wooden vessels.
Whip it smooth

A step called nayashi whips the raw lacquer into an even mixture.
Stir over gentle heat

The kurome step stirs and warms the sap slowly until excess water evaporates. What remains is a see-through, brownish, viscous coating material called refined lacquer.
Tint the refined sap

The refined sap is dyed for colored lacquerware. Japan imports 98% of its lacquer now, mostly from China.
Or dissolve a resin

Modern lacquers dissolve shellac or synthetic polymer, such as nitrocellulose or acrylic resin, in a thinner. Shellac-based types use alcohol.

Goes in
Ethanol Acrylic
Brush on thin coats

Lacquer goes on in several coats over a base, usually wood. Each layer stays thin so it can set properly.
Cure in a humid cabinet

Sap coatings do not really dry, since no solvent is involved. They harden over several days inside a humid cabinet known as an urushiburo. Modern lacquers harden as their solvent leaves.

End of the lineLacquer Next it goes into tin can, acoustic guitar, electric guitar and 10 more.

Worth repeating

The word urushiol comes from the Japanese name of the lacquer tree.
Compared with oil-based or latex paint, a modern lacquer finish usually dries harder and snaps more easily.
The English word lacquer traces back through Portuguese and Arabic to the Sanskrit word for lac.