Sanding Teak & Oily Woods: Solvent Wipe, Fresh Grits, Pace

Teak, ipe, cocobolo, and other oily hardwoods are gorgeous and durable—but their natural oils, silica content, and density make sanding tricky. Push too hard and you’ll polish (burnish) the surface shut so finishes won’t bite. Go too coarse and you’ll leave scratches that telegraph under oil or varnish. This guide shows a controlled approach that prioritizes clean abrasives, light pressure, and smart grit pacing so you get a crisp, even surface that actually accepts finish.

Why Sanding Oily Woods Is Different

Oily hardwoods contain extractives that migrate to the surface, especially when warmed by friction. They also tend to be dense and, in teak’s case, can contain silica that dulls abrasives quickly. The result: paper loads fast, heat builds, and the surface can burnish—leaving a slick, shiny feel that resists stain or varnish. A successful workflow keeps the surface cool, clean, and uniformly scratched with minimal pressure and timely sheet changes.

Tools & Supplies

• Hand sanding block (firm face) and a soft foam pad for gentle profiles.
• Random orbital (DA) sander with dust extraction (use low/medium speed) and a soft interface pad for edges/curves.
• Wet/dry silicon carbide sandpaper sheets: 120, 180, 320 (optional 400–600 for between-coat de-nibbing).
• Solvent for surface prep: mineral spirits, naphtha, or acetone depending on your finish system.
• Raking light and a pencil for light crosshatch “map” marks.
• Vacuum with brush head, clean microfiber towels, and tack cloth.
• Finish system: marine varnish, spar urethane, penetrating oil, or hardwax oil compatible with oily species.
• PPE: respirator (organics), eye/ear protection, and gloves.

Recommended Grit Sequence

• 120 grit: Initial leveling and scratch reset on weathered or machine-marked surfaces.
• 180 grit: Refinement step to remove 120 tracks and avoid premature burnishing.
• 320 grit: Pre-finish tightening for a smooth feel without sealing the pores shut. (Stop sooner for penetrating oils on very dense woods.)

Step-by-Step: Clean, Cool, and Consistent

1. De-grease before sanding. Wipe the surface with a compatible solvent (naphtha or mineral spirits; acetone for very waxy exotics) to remove surface oils. Let it flash dry fully. Degreasing prevents immediate loading and reduces heat smears.
2. Map and protect edges. Under raking light, draw a faint pencil crosshatch on the field. Tape knife-sharp edges and arrises so you don’t round them during the coarse step.
3. Shape and reset at 120. Wrap a firm block with 120 Grit (25-pack) or run a DA at a moderate speed with light pressure and an interface pad. Work in long, overlapping passes; finish with the grain. Replace sheets early—dull paper polishes, then scratches. Stop when your pencil map just disappears and machine marks are gone.
4. Vacuum, wipe, and solvent flash. Vacuum thoroughly, brush the abrasive face, and wipe the surface with a quick solvent pass. Allow complete flash-off before the next grit—this keeps paper cutting crisply at the refinement step.
5. Refine at 180. Switch to 180 Grit (50-pack). Slightly change your pass direction (then finish with-grain) so lingering 120 lines are obvious. Use feather-light pressure—let the abrasive do the work. If 180 seems to stall, you likely need a fresh sheet, not more force.
6. Final pre-finish at 320 (optional depending on finish). For film finishes (varnish/urethane) or high-touch pieces, take a brief, even pass with 320 Grit (100-pack). Keep strokes long and the pad dead-flat to avoid creating shiny burnished zones. For penetrating oils on very dense woods (ipe), stopping at 180–220 often yields better absorption and color uniformity.
7. Dust control and final solvent check. Vacuum twice in different directions and wipe with a clean microfiber. Do a fast solvent wipe only if your finish system allows it; let the surface return to a completely dry, cool state before coating.
8. Apply finish. For penetrating oils, flood on and keep wet per label, then wipe off uniformly with the grain. For varnish/spar, apply thin coats and avoid over-brushing—warm passes can pull oils to the surface and fisheye. Maintain a steady shop temperature for predictable cure.
9. Between coats (if using film finishes). After the first coat is fully sandable, de-nib with 320–400 by hand on a soft pad. Clean carefully and recoat within the specified window to maintain intercoat adhesion.
10. Final inspection. Under raking light, look for shiny “polished” islands (burnish) or dull streaks (clogged paper scratches). If needed, back up one grit locally, re-refine lightly, clean, and recoat.

Special Cases

Teak (boat trim & outdoor furniture): Teak’s oils are persistent. Degrease before every grit change, and consider stopping at 180–220 before a penetrating oil or marine varnish sealer coat.
Ipe & cumaru (ultra-dense): These burnish in a heartbeat. Keep pressure minimal and avoid going finer than 220 before oil; for film finishes, a gentle 320 pass is OK only if the surface still powders under the sheet.
Cocobolo, rosewoods (very waxy): Some finishes won’t cure on these without special primers/sealers. Do a thorough acetone wipe before the first coat, and test finish compatibility on an offcut.

Pro Tips

• Fresh paper, not more pressure. If cut slows, rotate to a fresh section or sheet. Pressure makes heat, which pulls oils up and polishes the surface.
• Block the flats, pad the curves. A firm block keeps panels true; a soft interface pad prevents edge dig-in on profiles.
• Short sessions, cool surface. Give the piece a moment between passes. Warm wood sweats oils—let it cool and flash off solvent before continuing.
• Alternate directions between grits. A slight diagonal shift reveals leftover scratches so you don’t lock them under finish.
• Test boards save time. Keep an offcut from the same batch. Prove your grit ceiling (e.g., stop at 180 for oil vs 320 for varnish) before committing to the whole piece.

Aftercare

• For outdoor pieces, plan seasonal maintenance: a quick clean and a light 320 de-nib before renewing oil or spar.
• Use pH-neutral cleaners; avoid strong detergents that strip oil finishes or soften young varnish.
• Address spills promptly—sunscreens and bug sprays can soften/coarsen film finishes on oily woods.
• Store abrasives flat and dry; humidity curls paper and weakens adhesion on the backer.

FAQs

• Can I start at 80 on weathered teak? Only if the surface is heavily ridged or gray. Take the briefest 80 pass, then move quickly to 120/180 to erase deep tracks and prevent burnish.
• Why does the surface look shiny before finish? That’s burnishing from heat/pressure or dull paper. Back up one grit with fresh sheets and lighten your touch.
• Should I wet-sand oily woods? Generally no before finish—water can trap slurry and raise fibers unevenly. Dry-sand, keep it cool, and solvent-wipe as needed. Wet sanding is fine between coats on fully cured film finishes.
• My varnish fisheyed—now what? Degrease, let dry thoroughly, scuff with 320, and apply a compatible sealer or tie-coat recommended for oily species, then resume finishing.
• What grit should I stop at for penetrating oil? Usually 180–220 for best absorption and even color. Going finer risks blotchy uptake on very dense woods.

Watch & Learn

Closing: Oily hardwoods reward restraint. Degrease early and often, keep pressure light, and climb a simple ladder—120 → 180 (→ 320 for film finishes). Work cool and clean, and your teak, ipe, or rosewood will take finish evenly and glow without swirl or burnish. Stock the three workhorse grits so you can stay disciplined at each step: reset with 120 (25-pack), refine with 180 (50-pack), and—when the project calls for it—tighten the field with 320 (100-pack).