Sanding & Finishing Reference: Grits, Woods, and Coat Counts by Finish Type

This is a quick-reference companion to the step-by-step Tru-Oil application guide — use that guide for a full walkthrough of one specific finish, and use this page to decide which finish to use, and to look up grit progressions and coat counts across all of them at a glance.

1. Grit Progression by Wood Type

How far you need to go before finishing, and whether you need to grain-fill, depends on whether the wood is open-grain (visible pores) or close-grain (tight, fills itself in effect).

Wood	Grain type	Grain fill needed?	Recommended prep sequence
Mahogany	Open	Yes, for a glass-flat film finish (oils can skip this if a slightly textured look is acceptable)	120 → 180 → 240 → grain fill → 240 (back to bare) → 320
Ash (swamp/open-pore)	Open	Yes	120 → 180 → 240 → grain fill → 240 → 320
Korina (limba)	Open	Yes, for gloss builds	120 → 180 → 240 → grain fill → 240 → 320
Walnut	Open, finer pore than mahogany	Optional — many builders leave walnut unfilled	120 → 180 → 240 → 320
Maple (hard/flame/quilt)	Close	No	150 → 220 → 320 → 400
Alder	Close	No	150 → 220 → 320 → 400
Basswood	Close, soft — sands fast, dents easily	No	150 → 220 → 320 (light pressure throughout)
Poplar	Close, can have green/purple streaks (cosmetic only)	No	150 → 220 → 320 → 400

Always sand with the grain at every grit, and wipe/tack-cloth between grits so you can see scratch patterns under raking light before moving on — skipped grits are the single most common cause of blotchy or streaky finishes.

2. Grit Progression by Part: Neck vs Body

Necks and bodies are prepped to different endpoints because they’re finished differently in practice, not because the wood itself needs different treatment.

Neck (back of neck + headstock face):

• Prep to 320–400 grit maximum. Necks almost always get a thinner finish (oil, or a thin satin lacquer) so a glass-flat 600+ prep is wasted effort — the wood’s own smoothness at 320–400 is what your hand feels once the thin finish is on.
• Pay extra attention to fret ends, the neck/heel transition, and headstock edges — these get handled constantly and any missed scratch there is the first thing players notice.
• Round over any sharp edges at the headstock and heel before your final grit, not after — sanding a finish coat to fix a missed edge means starting the finish over.

Body (front, back, sides, especially under a gloss finish):

• Prep to 320–400 minimum for oil finishes; if you’re building toward a sprayed gloss lacquer or poly, prep to 400 and let the finish’s own build-and-level-back process (see table below) take it further.
• Body edges/binding channels need careful hand-sanding — power sanders round over binding lines fast.
• Any dents need to be steamed out (damp cloth + iron) and re-sanded before finishing — a poly or lacquer build will not hide a dent; it will highlight it.

3. Finish Type Comparison

Coat counts below are for a full body; necks typically need roughly half as many coats since a thick build isn’t wanted there (see above).

Finish	Application	Sanding between coats	Typical coats (body)	Final buff / rub-out	Cure before buffing
Tru-Oil	Wiped on by hand/cloth, no spray gear	400-grit wet-and-dry or 0000 wire wool	6–10	800 → 1000 → 1500 grit wet, then compound + optional wax	48–72 hours
Danish oil / tung oil (pure or polymerized)	Wiped on, excess wiped off after 15–20 min	Light 0000 wire wool scuff, not full wet-sand	4–6 (thinner build than Tru-Oil, more of a “fed into the wood” finish)	Wire wool + wax only — these finishes don’t build a hard film to compound	24–48 hours between coats, ~1 week full cure
Boiled linseed oil (BLO)	Wiped on, heavy excess wipe-off (BLO is prone to gumming if left thick)	0000 wire wool between coats	4–8, thin coats	Wax buff only — BLO stays soft/low-build, never compound-buffed	24 hours between coats; full cure can take 2–3 weeks
Nitrocellulose lacquer	Sprayed, multiple thin coats per session	320–400 grit level-sand after initial coats have flashed off, before final coats	6–10 spray passes (often grouped in 2–3 coats per session over several sessions)	Wet-sand 600 → 1000 → 1500 → 2000, then compound + polish	2–4 weeks before final level-sand and buff (lacquer keeps shrinking as solvents fully evaporate)
Polyurethane (poly)	Brushed, wiped, or sprayed depending on product	320–400 between coats once fully cured (poly sands gummy if cured too little)	3–6 (poly builds thicker per coat than lacquer, fewer coats needed)	Wet-sand 800 → 1200 → 2000, then compound	24–72 hours between coats depending on product; 1–2 weeks before final buff

Reading the table: oils (Tru-Oil, Danish/tung, BLO) are “in-the-wood-plus-thin-film” finishes — more coats, but each one is thin and forgiving, and repairs are easy (sand back locally, reapply, blend). Lacquer and poly are true build finishes — fewer, thicker coats, a proper level-sand-and-buff cycle, and a full-strip-or-blend-carefully approach to repairs since a bad patch will show as a sheen mismatch.

4. Choosing a Finish

• Best for a first build / no spray equipment: Tru-Oil — see the full application guide for the complete process.
• Best for a fast, low-maintenance, “just feed the wood” look: Danish oil or BLO — lowest coat count, no film to ever crack, but least durable and lowest sheen ceiling.
• Best for a vintage-correct look/feel and repairability by a tech later: nitrocellulose lacquer — but requires spray equipment, a dust-controlled space, and patience for the multi-week cure.
• Best for durability with the least finishing skill required: polyurethane — most chip/scratch resistant, most forgiving to apply, but hardest to blend a repair into invisibly and can look “plasticky” if oversprayed too thick.

As with the Tru-Oil guide, all grit numbers and coat counts above are practical starting points from common builder practice, not a single universal spec — humidity, temperature, and the specific product you’re using will shift these numbers. Always test your full schedule on an offcut of the same wood first.