Finish Stainless Steel: 180–320 Grit & Scotch-Brite Guide

Want that clean, professional linear grain on stainless steel—no random swirls, no blueing, and no “patchy” sheen? The secret is a short, disciplined grit ladder and consistent stroke direction, finished with a non-woven pad. This guide shows exactly how to build a straight, even grain using 180 ? 240 ? 320 grits, when to go wet, and how to avoid the heat and loading that ruin stainless surfaces.

Why Sanding Matters for Stainless

Stainless steel work-hardens and heats quickly. Over-pressure polishes instead of cutting; aimless circles create visible swirls that catch light. A linear workflow—straight, overlapping strokes in a single direction—produces a uniform scratch field that looks intentional and hides seams. Balancing grit, pressure, pad hardness, and cooling prevents blueing and galling while keeping edges crisp.

Tools & Materials

• Rigid sanding block (flats) and thin foam pad (gentle curves)
• Random-orbit or inline sander with variable speed (optional; finish by hand to align grain)
• 9×11 in wet/dry silicon carbide or AO sheets: 180, 240, 320
• Non-woven pads (maroon/gray Scotch-Brite–type) for final uniforming
• Lubricant/coolant: water with a drop of dish soap or a light cutting fluid
• Raking/side light, pencil/Sharpie for guide-coats, straightedge
• Shop vacuum, microfiber cloths
• PPE: gloves, eye protection, respirator rated for fine metal dust

Recommended Grit Sequence

• 180 grit — Primary cut: remove existing swirls, oxidation, and scratches; establish the new grain direction.
• 240 grit — Refine depth and tighten the scratch field.
• 320 grit — Final linear blend before the non-woven uniforming pass.

Step-by-Step: Clean Linear Grain

1. Degrease and map. Clean the part and dry fully. Under raking light, mark defects and draw a faint guide line in the direction you want the grain to run. This line keeps every stroke aligned.
2. Primary cut at 180 (set direction). On flats, wrap paper around a rigid block. Make straight, overlapping strokes along the grain direction—no circles. If the surface is large, you can power-sand at moderate speed, then finish by hand with straight passes. For reliable bite, stock 180 grit (25-pack). Keep pressure light so you cut cool; if warmth builds, pause and cool.
3. Lubricate when needed. Stainless can load and smear as heat rises. Mist water with a drop of soap or apply a light cutting fluid. Wipe and re-wet often; a cool, wet cut keeps scratches crisp and shallow.
4. Refine to 240 (erase 180 completely). Re-map a faint pencil guide and step to 240 grit (50-pack). Repeat the same straight, overlapping passes. Your goal is not shine—it’s a tighter linear pattern with 180 fully gone under side light.
5. Final grit at 320 (tighten the grain). Step to 320 grit (100-pack). Use fresh sheets, minimal pressure, and longer uninterrupted strokes. Stop the instant the 240 pattern is uniformly replaced by a fine, even satin in the same direction.
6. Uniform with non-woven pad. Switch to a gray (finer) Scotch-Brite–type pad. Pull it in the same direction as your sanding. Two or three passes even out micro-variations without changing the grit signature you just created.
7. Edge & feature control. On outside corners, reduce pressure and shorten strokes so you don’t thin or brighten the edge. Inside corners or cutouts: wrap narrow strips around a dowel and keep the stroke direction consistent with adjacent faces.
8. Final clean & read the light. Vacuum, wipe with a clean microfiber, and inspect under raking light from several angles. Any cross-lines? Back up one grit locally, restore direction, and re-blend quickly at 320, then non-woven again.

Special Cases

Deep scratches/gouges: If a fingernail catches heavily, spot-level first with 120–150, then re-establish direction at 180 ? 240 ? 320. Keep the coarse work localized and blend out wide so halos disappear.
Brushed appliance panels: Factory brush often reads ~240–320. Test in a corner: a quick 320 pass + gray non-woven usually matches. Always align strokes with the factory grain.
Tubes/rounds: Use a shoe-shine (belt) motion with the strip pulled straight along the axis for a longitudinal grain, or rotate uniformly for a wrapped grain—stay consistent across the part.
Heat-sensitive assemblies: Near gaskets/adhesives, go wet, lighten pressure, and keep strokes short to avoid softening bonds.

Pro Tips

• Direction is everything. Pick a grain direction once and never break it—your eye will catch any cross-line later.
• Moderate speed, light pressure. Let grit cut; pressure makes heat and glazing.
• Fresh sheets win. Dull paper polishes stainless, widening scratch scatter and killing uniformity.
• Block for flats, thin foam for curves. The backer controls geometry; fingers create flats and wobbles.
• Use the light. Raking/side light is your cheapest QC. Advance only when the previous scratch is 100% gone.

Aftercare

• Remove any lubricant residue so coatings or decals adhere properly.
• For fingerprints and daily care, use a stainless-safe cleaner and soft cloth; avoid abrasive pads that cross the grain.
• Protect high-touch zones with consistent cleaning in the same grain direction to keep the finish even.

FAQs

• Can I jump from 180 straight to 320? You’ll spend longer at 320 and risk mixed scratch depths. 180 ? 240 ? 320 stays cooler and more uniform.
• Dry or wet? Dry is fine for small areas; go lightly wet for larger panels to control heat and loading.
• Why do I see “clouds” after finishing? Likely uneven pressure or direction changes. Re-establish direction at 240, then 320, then a non-woven uniforming pass.
• Non-woven pad color? Maroon cuts more; gray is a finer uniformer. Start with gray for finishing; use maroon only if you need a touch more bite before returning to 320.
• Will RO sander marks show? Yes if you don’t finish by hand. Always end with straight, with-grain strokes to mask the orbit pattern.

Watch the Linear Finish Flow

Closing: A pro stainless look is simple: pick a direction, cut at 180 to set it, refine at 240, finish at 320, and unify with a gray non-woven—keeping strokes straight and pressure light. Control heat and clean between steps, and your panels will read as one smooth, intentional grain from every angle.