Choosing the Correct Sanding Grit

Matching Grit to the Job, Not the Other Way Around

One of the most common mistakes in any finishing process — woodworking, collision repair, or industrial fabrication — is not using the wrong disc. It is using the right disc at the wrong stage. Grit selection should follow the condition of the surface and the goal of that specific step, not just whatever is already loaded on the sander.

The disc already loaded on the sander is rarely the right one for the next stage.

The First Question Isn’t Grit — It’s Paint

Before you think about a number, answer one thing: has this panel been painted yet?

That single question sorts almost every job, because the two LEVEL disc systems divide on exactly that line.

	Alpha	Omega
When	Before paint	After paint and clear
Grits	P80–P800	P1200–P2500
The job	Remove material	Level a finish, then erase your own scratch
Working on	Bare substrate, filler, primer, e-coat	Paint and clear coat
Interface pad	Optional	Required — Piston Hook
	Shop Alpha	Shop Omega

If you are stripping a coating, shaping filler, grinding metal, leveling gelcoat, feathering an edge, or knocking down primer, you are in Alpha’s range and you should be somewhere between P80 and P800.

If the panel is painted and cleared and you are chasing orange peel, a run, dirt, or a nib, you are in Omega’s range and you should be somewhere between P1200 and P2500. Reaching for an Alpha disc here is how a small defect becomes a refinish.

P80 and P2000 — opposite ends of the same job. Which one you reach for is decided before you pick a number.

Then Start With the Material and the Damage

Within Alpha’s range, two more questions set your starting grit: what is the material, and what is currently on the surface?

Heavy paint, filler, rust, or significant surface damage calls for a coarser, more aggressive grit — this is where TiVFE self-sharpening ceramic and EAP Technology are built to remove material quickly across wood, body filler, metal, carbon fiber, and painted surfaces without loading up or losing consistency.

Once that heavy material is gone and you are working a leveled but still-rough surface, the job shifts from removal to refinement. That is a different grit range, and eventually a different disc system entirely.

Coarse Alpha grit is built to move heavy material without loading up or losing its scratch.

Coarse to Fine: Why the Progression Matters

Skipping grit stages is the fastest way to create more rework than you started with. Every grit level leaves its own scratch pattern, and each subsequent grit’s job is to remove the previous stage’s scratches while leaving a finer pattern behind. Jump too many steps — say, straight from heavy P150 removal to a P2500 refining disc — and the finer grit simply cannot remove the deeper scratches underneath it, leaving inconsistent results that show up under paint, primer, or clear coat.

A typical progression moves from aggressive stock removal, through a mid-range leveling stage, into a fine refining pass:

• Coarse — heavy removal: P80–P220. Alpha grits, built to strip material fast on wood, filler, metal, and painted surfaces.
• Fine — stock refinement: P320–P800. Still Alpha, used to level primer, blend, and prep the surface for paint.
• Leveling: P1200 and P1500. Omega’s leveling discs correct orange peel and debris in fresh clear, creating a consistent, even scratch pattern that is easier to refine.
• Refining: P2000–P2500. Omega’s refining discs deliver the final pass before polishing, for smoother refinement and better depth of image.

Every grit exists to erase the one before it. Skip a step and the finer disc has nothing to cut against.

Where to Start, by Job

The job in front of you	Start at	System
Stripping heavy coating build	P80	Alpha
Stripping a single coat	P120–P150	Alpha
Rough filler shaping	P80–P120	Alpha
Finishing filler to shape	P180	Alpha
Feather edging	P150–P220	Alpha
Leveling primer / removing guide coat	P220–P400	Alpha
Final blending before paint	P400–P800	Alpha
Heavy orange peel or heavy debris in clear	P1200	Omega Leveling
Average orange peel, typical dirt or nibs	P1500	Omega Leveling
Light defect, going straight to cut and polish	P2000	Omega Refining
Refining a P1500 scratch, killing pigtails	P2500	Omega Refining

Signs You’re Using the Wrong Grit

• Too coarse for the stage: visible deep scratches remain after what should be a finishing pass; excessive material removed for a stage that only needed light correction; pigtails showing up in a surface that should be clean.
• Too fine for the stage: the disc glazes over or stops cutting effectively; working time drags on without visible progress because the grit cannot handle the material still present.
• Wrong system entirely: you are using a pre-paint grit on a clear-coated panel, or trying to correct heavy filler with a finishing disc. The first shows up as damage; the second shows up as a wasted afternoon.

Why Consistency of Scratch Pattern Matters as Much as Grit Number

Grit number alone does not guarantee a clean result — how consistent that grit’s scratch pattern is matters just as much.

This is where disc construction makes a real difference, and it is measurable. Two even passes with a 6" P1500 on a 2.5mm DA sander produce a visibly tighter, more uniform scratch with an Omega Leveling disc than with the industry leader’s disc at the same grit on the same machine. Same number, different result — because Omega’s latex-based construction carries abrasive through the material rather than as a surface layer on multi-layered film, so it wears evenly and holds its pattern.

A consistent scratch makes the next stage predictable. An inconsistent one means the next grit is chasing outliers instead of removing a uniform pattern, which is where extra passes and rework come from.

Same P1500, same machine — construction is what makes the scratch pattern consistent.

Dry Beats Wet at the Refining Stage

The traditional final step before polish is wet sanding, usually a P3000 with water. The Omega system replaces it.

Two even passes of a dry P2500 over a P1500 scratch finish tighter than the industry-standard wet P3000 over the same P1500 — no water, no mess, no cleanup. If you have been budgeting a wet sanding step into every job, that step comes out of the process without costing you finish quality.

Technical Reference

Stage	Grit Range	Recommended Disc	Best For
Heavy removal	P80–P220	Alpha Leveling Disc	Wood, body filler, steel, aluminum, carbon fiber, gelcoat, paint stripping
Fine / pre-paint	P320–P800	Alpha Leveling Disc	Primer leveling, guide coat removal, blending, final prep before paint
Leveling	P1200 & P1500	Omega Leveling Disc	Orange peel, dirt and debris in paint and clear
Refining	P2000–P2500	Omega Refining Disc	Final scratch pattern before polishing; replaces wet sanding

Alpha grits: P80, P120, P150, P180, P220, P320, P400, P600, P800. Omega grits: P1200, P1500, P2000, P2500.

Going Deeper

For grit-by-grit detail on either system — what each individual disc does, what it leaves behind, and how to run it — see the Alpha Leveling Discs and Omega Leveling & Refining Discs guides.