Chapter 7

Abrasives: what to buy and how to keep it clean

Buy abrasives for a named operation, not as one long ladder of numbers. Wood preparation, ground shaping, between-coat levelling, roiro polishing, and decoration reveal use different materials. The grade number matters, but so do the grading standard, abrasive grain, backing, lubricant, support, and condition of the lacquer.

Abrade only a mechanically ready layerA dry-looking coat may still be soft below the surface. Test a control swatch before sanding. If the lacquer smears, rolls, clogs the abrasive at once, or takes a fingerprint, stop and return it to stable curing conditions. Treat a breakthrough or soft layer as uncured urushi and follow Chapter 2.

Start with the operation

Operation	Useful abrasive form	Buying question
Prepare bare wood	Quality coated paper on a flat or shaped support; cutting tools where the method calls for them	What surface must remain for the first lacquer coat: crisp tool finish, open grain, or uniformly sanded wood?
Shape a ground layer	Whetstone, abrasive paper, or another method-specific rigid cutter	Will the tool preserve the plane, curve, rim, and edge rather than follow every hollow?
Level a cured middle coat	Waterproof coated abrasive, fine whetstone, or polishing charcoal	Does the method specify water, a supported sheet, or a dressed charcoal face?
Prepare for uwa-nuri	Fine whetstone or polishing charcoal in traditional Wajima work; a documented paper stage in some modern methods	Can it remove dust and high spots without exposing the layer below?
Produce a roiro finish	Polishing charcoal, then the specified oil and powder stages, rubbed lacquer, and final polishing powder	Are you buying the materials for one complete published sequence rather than substituting by name?
Reveal maki-e or shell	A technique-specific supported abrasive progression	How hard and how high is the decoration compared with the surrounding lacquer?

Grit numbers need a surname

There is no universal grit scale. FEPA identifies coated-abrasive grades with a P prefix and defines each grade as a particle-size distribution. ANSI and JIS use other standards. Micro-Mesh has its own proprietary scale. Its maker describes the conversion chart as a guide to a working range and provides separate columns for different Micro-Mesh product families and materials. The numbers are not interchangeable with FEPA grades. (FEPA; Micro-Surface)

Label	What it tells you	What to record
P600, P1000, P2000	FEPA coated-abrasive grades	Keep the P, brand, product line, and whether the sheet was used wet or dry.
600, 1000, 2000 without a prefix	An incomplete description unless the maker identifies the standard	Find the standard on the package or technical sheet. Do not guess from the number.
Micro-Mesh 1500 to 12000	A separate family with product-specific grade numbers	Record the Micro-Mesh type as well as the grade. Regular, MX, and other lines are made for different materials.
Charcoal or whetstone	A material name, not a fixed paper equivalent	Record the type, source, dressed shape, lubricant, and the coating stage.
Tonoko or migakiko	A powder name that does not guarantee one particle distribution or recipe	Record the supplier, product, carrier, cloth or hand tool, and stage.

Never write only "#1000" in a process recordWrite the complete product label. A repeatable note looks like "Brand X waterproof P1000, water, hard flat block," not "fine paper."

A sensible first paper kit

Tamenuri Studio suggests that beginners keep quality papers from roughly 320 through 2000 or 3000, plus Micro-Mesh from 1800 through 12000. Read that as a broad workshop inventory, not a single continuous progression. The same guide uses 400 to 600 paper for one fuki-urushi practice sequence and much finer materials for a polished pen build. (Tamenuri Studio)

For a first purchase, choose one good waterproof coated-abrasive product line and buy the grades named in the method you plan to follow. Add the adjacent grade on either side for test panels. This keeps the backing, grain, and grading system consistent while you learn what each step removes.

Buy	Why	Check before ordering
Waterproof abrasive sheets	They support the wet-levelling methods used for many cured lacquer layers.	The grading system, abrasive material, backing flexibility, sheet size, and maker's wet-use instructions
One hard flat block	It keeps paper from dipping into low spots on planes and broad curves.	A clean face, crisp edges, and a size that fits the work
Several shaped or firm flexible pads	They spread pressure over cylinders, convex surfaces, and gentle hollows.	A shape that matches the object without rounding rims or corners
Small water trays and clean rinse containers	They keep slurry controlled and make it possible to separate stages.	Enough containers that coarse residue never enters the fine stage
Raking light and magnification	They reveal the old scratch pattern, glossy low spots, and edge breakthrough.	A movable light and magnification strong enough for the scale of the work
Labelled storage sleeves or boxes	They prevent an unidentified offcut from returning to a nearly finished surface.	A separate compartment for every grade and product line

Micro-Mesh is optional. Buy it only when your chosen method uses it and start at the grade recommended by its own chart or by the complete method. A full set does not replace the need to remove the previous scratch pattern before moving finer.

Traditional cutting and polishing materials

The Wajima Museum's production sequence shows why one bag labelled "abrasive" cannot cover the craft. Coarse whetstones cut early ground coats. Fine whetstones or polishing charcoal refine middle coats. Polishing charcoal levels the hardened top coat. Oil and tonoko remove finer scratches during roiro, followed by rubbed lacquer and a final polishing compound. (Wajima Museum of Urushi Art)

Material	Documented role	Buying note
Toishi, whetstone	Shapes ground layers and refines prepared lacquer surfaces. Wajima practice uses different stones at different stages.	Buy the stone named by the method. Shape and dress it for the object's plane or curve.
Togi-sumi, polishing charcoal	Wet-levels middle and top lacquer. The Wajima Museum records charcoal made from woods such as tung and magnolia.	Buy from an urushi supplier and state the intended stage. "Charcoal" alone is not a specification.
Suruga charcoal	Appears in Wajima accounts for preparation before the top coat and for roiro levelling.	Choose the form and grade supplied for lacquer polishing, then dress the working face to the object.
Tonoko	A fine clay used in sabi mixtures and, with oil, in a roiro scratch-removal stage.	Keep foundation material separate from polishing stock. Follow the polishing method's preparation and filtration instructions.
Jinoko	Fired diatomaceous earth used in traditional Wajima ground layers.	This is a ground-building material, not a general substitute for final polishing powder.
Migakiko	A fine hand-polishing powder. The Wajima Museum notes deer-horn and titanium-white forms.	Buy the named product for the final system. Do not infer particle size from colour or material name.

The Japan Artisan Foundation's togimono account also shows that abrasive shape is part of the tool choice. Stones may be prepared with round, pointed, or concave faces to suit the work. A fine abrasive on the wrong support can damage the form just as readily as a coarse one.

Keep every stage separate

Cut full sheets into manageable pieces and mark the grade on the back before use. If water erases the mark, store each grade in a labelled tray.
Use a separate block, pad, cloth, water container, and towel for fine polishing when possible. At minimum, clean them fully before moving to the next stage.
Discard a sheet that falls on the floor, picks up a hard particle, curls away from its support, or stops cutting cleanly. Saving one small piece can cost another lacquer coat.
Do not return a used sheet to the clean stock. Dried lacquer crumbs can scratch more deeply than the printed grade.
Keep water stages and oil stages distinct. Oil left before a later lacquer coat can create a wetting or adhesion problem.
Clean the object before inspection. Wet slurry fills scratches and makes the surface look finer than it is.

Control dust and slurry

Wet work contains residue but does not make it harmless. Keep slurry off bare skin, collect it at the bench, and do not rinse unknown lacquer and mineral waste into a household drain. Dry sanding can release wood, cured coating, clay, charcoal, and polishing-powder dust. NIOSH identifies inhalation and eye or skin contact as exposure routes for wood dust and lists respiratory, eye, and skin effects. Use source capture for machine sanding, avoid compressed air, and follow the eye and respiratory guidance in Chapter 11. (NIOSH Pocket Guide, Wood dust)

If a layer may be soft or uncured, do not dry-sand it. Isolate the object, test a control, and use the recovery sequence in Chapter 21.

Watch the material differences

Papers, charcoal, stones, and powders, 16:55. Tamenuri Studio compares the forms used across urushi work. Treat each demonstration as part of its stated method rather than converting every material to a paper grit. Watch on YouTube.

Continue from here

Sanding and polishing explains progression design, scratch inspection, supports, edges, slurry, and published schedules.
Shitaji covers jinoko and tonoko as ground-building materials.
Roiro-nuri covers charcoal levelling, dozuri, rubbed lacquer, and final hand polishing.
Curing and troubleshooting gives the readiness tests to use before abrasion.

Sources for this chapter