Finishing fuki-urushi chopsticks and spoons: sanding, additional coats, and polishing sequence

What goes wrongTiny wood rays create pinpoint crevices that trap whetstone powder during the final roiro-migaki, leaving visible dark specks in the surface. The same commenter notes that applying the next coat too soon—when the previous one looks and feels cured but is not—compounds the problem.

What recovers itBrush out the trapped powder and apply additional uwazuri coats to bring the crevices up to level. Alternatively, accept the crevices as part of the wood's character. For future work, invest more effort in the initial sanding and sealing stages so the crevices are filled before the decorative coats begin.

Apply fuki-urushi sealing coats

Wear nitrile gloves and rub raw urushi on with the fingers in a fairly thick but non-pooling layer. Allow 24 hours of curing between coats at 70–90 % humidity. Apply five coats.

Apply uwazuri leveling coats

Apply five further coats using the uwazuri technique, again allowing 24 hours between coats at 70–90 % humidity. After each coat perform do-zuri and then tsuya-age.

Burnish with aluminum oxide

Rub a brick of aluminum oxide (waxy-bound) onto a piece of cotton canvas wrapped around a rubber backing. This step is described as experimental rather than conventional.

Burnish with iron oxide

Repeat the burnishing motion using iron oxide (jeweler's rouge) on the same cotton-canvas-and-rubber setup.

Perform roiro-migaki

Prepare a slurry of powdered Japanese natural whetstone and water. Apply with bare hands to achieve the final mirror polish.

Sand raw wood before the first seal

Sand with 320 grit, lightly wet the surface to raise the semi-loose grain, sand again at 320 and progress to 400–500 grit, then begin the fuki sealing coat. Avoid sanding raw wood above 600–800 grit before the first lacquer layer.

Allow the first penetrating coat to cure fully

Leave the first diluted or penetrating coat in the furo for at least one week, preferably two, then move to ambient humidity for a day or two before applying the next layer.

What was reported

• Chopsticks and spoons finished by fuki-urushi can be sanded to 5000 grit and then have further coats of ki-urushi applied until a glassy surface is achieved; the number of coats is a matter of personal satisfaction rather than a fixed requirement. ↗
• A workable finishing sequence for chopsticks involves five fuki-urushi coats, five uwazuri coats, aluminum-oxide burnishing, iron-oxide burnishing, and a final roiro-migaki with whetstone powder and water. ↗
• The aluminum-oxide burnishing step is described as an experiment rather than a conventional part of the sequence. ↗
• Sanding raw wood above 600–800 grit before the first lacquer coat does little; it is better to sand at 320, wet the surface to raise the grain, re-sand at 320, progress to 400–500, and then begin the fuki seal. ↗
• The first penetrating or diluted coat should be left in the furo for at least a week, preferably two, before the next layer is applied, even though it may look and feel fully cured sooner. ↗
• Several factors influence how much the wood darkens under fuki-urushi: the smoothness of the initial sanding, the degree of dilution, the speed of initial curing (slower yields lighter colour), the specific type of raw lacquer used, whether processed rather than raw lacquer is chosen, the number of layers, and the passage of time (finished objects often lighten over months or years). ↗
• Special raw lacquers formulated specifically for fuki-urushi darken the wood very little, are often used undiluted, and tend to separate quickly so they must be mixed well before use. ↗
• Metal powders (tin, silver, gold) can be used to fill wood crevices as an alternative to additional lacquer coats. ↗
• The practitioner in the opening post has completed six coats of raw urushi by the fuki-urushi technique and is considering whether to sand and re-apply or to accept the current colour as finished. ↗

Whether uwazuri coats should be used to level visible crevices