Sanding For A Hardwax-Oil Finish

New Installation or Renovation

Step One: Pre-sand with belt grinder up to 60 grit

Step Two: Sand across the grain with 60 grit

Step Three: 80 grit

Step Four: Fill Visible Joints and Gaps

Step Five: 80 grit

Step Six: 120 grit

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New Installation with minimal height discrepancies in floor

Step One: 40 grit

Step Two: 60 grit

Step Three: 80 grit

Step Four: Fill Visible Joints and Gaps

Step Five: 80 grit

Step Six: 120 grit

New Installation

Step One: Use 40 grit  if the flooring has large differences in height between the individual wooden elements OR use 60 grit if the flooring has only small differences in height between the individual wooden elements

Step Two: 80 grit

Step Three: Fill Visible Joints and Gaps

Step Four: 80 grit

Step Five: 120 grit

Step Six: Check surface quality and perform additional sanding steps if necessary (up to G150). Change to a single disc machine for the final sanding step.

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Renovation

Step One: Use 16 grit if the flooring has a thick finish layer, large amount of dirt and stains or deep scratches OR use 24 grit if the flooring has a thin finish layer, normal amount of dirt and stains or scratches

Step Two: 36 grit / 40 grit

Step Three: 60 grit

Step Four: 80 grit

Step Five: Fill Visible Joints and Gaps

Step Six: 100 grit

Step Seven: 120 grit

Step Eight: Check surface quality and perform additional sanding steps if necessary (up to G150). Change to a single disc machine for the final sanding step.

New Installation

Step One: Use 40 grit if the floor has large differences in height between the individual wooden elements) OR use 60 grit if the floor has small differences in height between the individual wooden elements

Step Two: 80 grit

Step Three: Fill Visible Joints And Gaps

Step Four: 120 grit

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Renovation

Step One: Use 16 grit if the floor has a thick finish layer, large amount of dirt and stains or deep scratches OR use 24 grit if the floor only has a thin finish layer, normal amount of dirt and stains or scratches

Step Two: 40 grit

Step Three: 60 grit

Step Four: 80 grit

Step Five: Fill Visible Joints And Gaps

Step Six: 120 grit

• Weathered/grey wood (no heavy film): Start P60 → P80. Optional P100 if needed.
• Old film finish or deep ridges: Start P40 → P60 → P80 (then stop, or P100 if still rough).
• Softwoods (cedar/pine) in good shape: Often P60 → P80 is enough.

Deck walking surfaces: Do not exceed P100—smoother than that can reduce traction and oil uptake.
Exterior furniture/handrails (not walking surfaces): P120–P150 is acceptable.

Before you start

1. Dry wood only. Moisture content max. 20%. Avoid sanding right after rain or washing.
2. Fix hardware. Set or re-drive any protruding screws/nails 1–2 mm below the surface. Replace damaged boards.
3. Clear the surface. Sweep, scrape off any blobs, and remove staples or metal that will tear belts.
4. Coatings check. Thick paint/varnish? Mechanically remove the bulk first (scraper/planer) to avoid clogging belts.

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Sanding technique (belt sander)

1. Orientation: Sand with the grain/board length. On cupped boards, your first coarse pass can be a light diagonal to knock down highs, but finish with the grain.
2. Flat & moving: Keep the plate flat; let the sander’s weight do the work. Don’t tilt. Keep a steady pace; overlap passes by ⅓”.
3. Edges first (coarse grit): Break down high edges very lightly to avoid rounding. You want crisp arrises for grip and a neat look.
4. Progress grits: Vacuum between grits. Don’t skip more than ~one step (e.g., P40→P80 only if scratches are removed).
5. Watch for issues:
   • Clogging/burn: Swap belts as soon as you see resin or burn marks.
   • Waves: Slow your pace; widen your stance; don’t push down.
   • Swirl marks: Usually from switching to a random-orbit—finish final passes with the belt sander along the grain.

Edges, corners & details

• Use an edge/detail sander or a sanding block with the grain around posts, walls, and steps.
• Don’t try to sand inside board gaps; clean them with a scraper or thin tool instead.
• For stair treads: treat them like deck boards—stop at P80–P100.

Clean-down

1. Vacuum thoroughly (boards and gaps).
2. Stiff-brush the surface to lift fine dust from open grain, then vacuum again.
3. Inspection under raking light: No paint/old finish, no shiny patches, scratches removed, edges still crisp.
4. Ready for finishing: Proceed once dust is removed and the surface is dry. For oil finishes, a P80–P100 profile is ideal for even absorption and long-term maintenance.

• DO keep fasteners sunk, belts fresh, and passes overlapping.
• DO stop at P80–P100 on deck walking areas (traction + oil uptake).
• DON’T over-round board edges.
• DON’T sand damp wood.
• DON’T rush grit jumps—remove the previous scratch pattern before moving on.