How to Read Sanding Pads: the Right Grit

The short answer

Here is the rule that governs nearly every sanding pad decision: match the grit to how much material you are removing, then match the pad style to how the pad attaches to the sander. A coarse grit like P80 or P120 removes stock fast but leaves a deep, visible scratch; a fine grit like P400 or P600 cleans up, de-nibs and leaves a surface a paint film will sit on. The pad style decides the rest: a PSA (pressure sensitive adhesive) pad sticks straight to the sander's back plate, a perforated pad vents dust out through the holes, and a holeless solid pad is a continuous sheet you clamp or tape on. The two scenarios where the rule bends: very soft solid wood, where even P60 can dig too deep, and thin laminate, where the heat from a coarse grit can warp the panel. If your job is everyday furniture and panel prep, start in the P120 to P240 band, keep the tool below the pad's rated speed, and confirm the pad sits flat on the back plate before you cut into stock. The full range of PSA, perforated and holeless pads we supply is on the sanding disc range, and keep the abrasives glossary open whenever a label term is unfamiliar.

One number deserves its own line up front, because it drives more enquiries than any other: P800. On a two-coat paint system it is usually the last de-nib grit before the topcoat; on wood or laminate you commonly jump past it. What P800 is and is not, you will see in its own section below.

Two habits that turn this from guesswork into a repeatable spec: always state the grit standard you are buying to (FEPA or ISO 848), and always match the pad style to the machine before the pad goes anywhere near the surface. Everything below is the reasoning behind those two moves.

How sanding pads actually work

A sanding pad is a coated abrasive built from three parts: the grain, the paper backing, and the bond that holds the grain to the paper. The grain is what cuts. The paper is what carries it and sets how much force the pad takes. The bond is what decides how long the cut stays honest before the grain sheds. Those three trade against each other in one fixed way: the coarser the grain, the heavier the paper and bond you need to hold it; the finer the grain, the lighter the paper so the cut goes soft and controlled.

Most stock sanding pads run aluminium oxide grain, because it is tough, economical, and cuts predictably on wood, primer and paint. Silicon carbide on a glass paper shows up on the fine end, where a cooler, sharper cut matters more than sheer removal. The paper weight steps up with the grit: a P60 body paper is stiff enough to take pressure, while a P400 paper is light enough to flex with the surface and avoid a deep scratch on the topcoat.

Before you buy, read the pad face:

Grit number — the FEPA or ISO 848 size class, printed on the pad face or the packaging.
Grain type — aluminium oxide, silicon carbide or ceramic, named or coded by colour.
Diameter and style — 5 inch or 6 inch, PSA, perforated or holeless, so it matches the back plate.
Colour code — most makers colour-code the grit band; learn one and you can pick a pad in the dark.
Batch or lot — the code that ties the pad to an inspection record, which is what a request a quotation conversation asks for on any bulk order.

The one number you should not read off a shelf and trust is the maximum working speed: for a specific model that figure has to come from the pad maker, so confirm the rated speed against the model and keep the tool below it.

How to read the grit number on the pad

The grit number on a sanding pad is a FEPA or ISO 848 designation: the higher the number, the finer the grain and the lighter the cut. On most stock sanding pads the full page is one P800 grit number stamped on the face, and that is exactly why people assume P800 is the default — it is the number printed on the pad that finishes the most paint systems. The FEPA scale is what most international buyers quote, so name the standard in every enquiry and you avoid the classic mix-up where the same number on one scale does not match the same number on another; the reference is at the FEPA grit standard.

A short ladder to keep in your head when you walk the floor:

P60 – P80 🛠️ — heavy stock removal, spot repair, breaking down a gloss coat.
P120 – P180 🪵 — general prep, primer knockdown, first step on a raw panel.
P240 – P320 📏 — blend filler, even out the panel, prepare for the next coat.
P400 – P800 🎨 — finishing band: de-nib, clean up, bring the surface to a state a topcoat will sit on.
P1000 – P2000 ✨ — polish and de-nib the paint or clear coat itself, not the primer.
P3000 – P5000 💎 — the very fine end: de-nib, close the surface, bring out the mirror on a final coat.

Two places that ladder bends: on soft solid wood the coarse end does less work than people expect, because P80 digs deep and the grain runs fast; and on a very hard coated surface, the fine end wants to skim rather than dig, which is where P1000 and up do the real work.

What P800 actually does — and where it does not

Because P800 comes up in so many enquiries, it earns its own section. P800 is a fine grit, and its whole job is to de-nib and clean a surface that is already close to its final state, not to remove stock. On a two-coat paint system it is normally the last grit before the topcoat: it clears the nubs and small defects that P400 leaves behind, and it keeps the whole surface in one band of scratch depth so the topcoat sits evenly. A lot of the value in P800 is that it keeps the scratch pattern uniform rather than leaving deep marks that the topcoat has to fight.

Where P800 does not belong is as a first pass. If you run P800 over coarse scratches or raw filler, you are asking a fine pad to do a coarse pad's job, and it will glaze and load instead of cutting. The sequence has to run fine on top of coarse, never the other way. If you have P400 and P1000 and no P800, you can still work: P400 does the bulk of the de-nib and P1000 polishes on top, though you lose the step that sets the topcoat's scratch depth. And on a wood or laminate sequence you often jump P800 entirely and go P400 to P600, because the surface under a film of oil or wax does not reward the P800 step.

Sanding a two-coat paint system, end to end

The 800 grit earns its reputation inside a paint system, and reading the whole sequence is where the P800 sits. A practical two-coat sequence on a primed panel, with 6 inch perforated pads on a through-flow machine, runs like this:

P180 – P240 to cut through the filler or old gloss and bring the panel back to even. This is the heavy-removal step; the perforations keep the corners from packing with dust.
P320 to close the panel and even out the scratch so the next coat sits flat.
P400 – P600 to prep the first topcoat, de-nib the primer, and bring the scratch to a shallow, uniform band.
P800 (the 800 grit) as the last de-nib pass before the topcoat, clearing the small defects and setting the scratch depth the topcoat will follow.
P1000 – P2000 after the topcoat, on the cured paint itself, to de-nib and bring the clear to a state a polish will finish.

The thing the sequence is really doing is keeping every layer of scratch finer than the one before it. The moment you jump two steps, the coarser scratch survives under the next coat and shows through as a shadow once the paint cures. That is the single most common reason a panel looks sanded but not finished. For the sequence by coating type, the automotive repair sanding use notes walk through the grits by stage, and the sanding disc range is where you confirm the pad size that fits your through-flow machine.

Grit by material: a quick reference

Material changes the starting grit even when the tool is the same. The list below is the starting point, not a rule, because the finish you are aiming for and the thickness of the stock both shift the band in one direction or the other.

Raw solid wood 🪵 — P80 to P120 to remove, P240 to P400 to bring it even. Soft species dig deep, so start finer than you would on a hardwood and keep the pad moving.
MDF and engineered wood 🧱 — P120 to P180 to remove, P240 to P320 to bring it even. MDF packs a pad fast because it is soft and dusty, so a coarser grit and a through-flow pad beat a fine grit held in one spot.
Laminate and veneered panels 🪟 — P180 to P240 to prepare, P400 to P600 to finish. Thin, so a coarse grit digs through the film; work in steps and check the edge between grits.
Primer and filler 🚗 — P180 to cut, P320 to close, P400 to P800 to prep the topcoat. This is the band most sanding pads spend their life in.
Cured paint and clear coat 🎨 — P800 to P1000 to de-nib, P1500 to P2000 to bring out the mirror. Do not start on cured paint with a coarse grit; you will cut through the coat.

The rule underneath the list is the same one from the top of this page: match the grit to the material and the finish, and let the grain decide how the cut feels. Aluminium oxide is the grain to default to on wood, primer and paint; silicon carbide is the pick where a cooler, sharper cut on a finished coat is the goal. For the sequence by species, the woodworking sanding use notes give the grits to reach for, and the 5-inch mesh sanding discs are the through-flow pads that handle the dusty engineered-wood work.

Perforated, holeless or PSA: reading the pad construction

Pad construction is where most of the choice happens once the grit is set. You will see three styles on most stock sanding pads, and the style is where the differences show up.

Perforated pad 🌀 — a disc with a pattern of holes across the face. The holes let dust escape instead of packing under the paper, which keeps the corners cleaner and the cut cooler. The perforated pad is the style to reach for on through-flow dust-extraction machines, where the holes line up with the machine's ports and the dust has somewhere to go.
Holeless pad 🛡️ — a continuous solid sheet, no holes. It is stiff and tends to last through steady work, because there is no hole to work at the edges. The holeless pad suits the firm, even passes where corner life matters.
PSA pad 🧲 — the style most shops think of first: a hook-and-loop or pressure sensitive adhesive face that sticks straight to the sander's back plate with no clamp. PSA is the default for most orbital machines, because the pad is on and off the machine in seconds and the grit sequence means you are changing pads a lot.

You can compare the two main styles side by side on the 6-inch non-hole sanding disc page against the 5-inch mesh sanding discs, and the full set of sizes is in the sanding disc range. If you are not sure which style a job is, default to the style that suits the dust: more dust, more vents; less dust, a holeless sheet will serve.

Random orbital: what the machine does to the pad

Random orbital changes the job more than the grit does, because the pad is not running in one direction. The orbital tool spins the pad while it circles around the surface, so the scratch pattern lays down in many directions instead of one spiral. That is why an orbital blends marks evenly and a straight grinder does not; it is also why a pad on an orbital wears differently than the same pad on a drum or a belt, because the corners of the pad work as hard as the middle.

Two things the machine decides for you:

Back plate size. The pad has to sit on a back plate of the same diameter. A 5 inch pad on a 6 inch plate leaves the corners of the plate exposed, which is how you get a scratch ring on the part; a 6 inch pad on a 5 inch plate overhangs and the edges curl.
Speed ceiling. Keep the tool's maximum speed below the pad's rated speed and the corners stay glued down. That is the single most common cause of edge curl on an orbital machine: the tool is faster than the pad was made for, and the corners let go.
Dust path. An orbital throws dust in a wide ring around the pad, not in one line. A handheld extractor at the work pulls the plume away; without it the dust lands back on the surface you just cleaned.

If you do not have the tool's speed range in hand, the rule is simple: confirm the tool's maximum speed against the pad's rated speed, and run at the lower of the two. That is what the OSHA portable power tool standard is built around; OSHA 29 CFR 1910.244 is the plain-language baseline at OSHA 29 CFR 1910.244 — portable power tools.

Speed, dust and safety, in plain terms

Sanding pad work is a dust and a flying-chip hazard, and the honest message is that compliant use lowers the risk rather than removing it. Keep the guard fitted on the tool where one is designed, confirm the pad diameter suits the guard and the back plate, and run the tool at a speed the pad was made for. Wear eye and face protection at the machine, and on dry sanding with a real dust load, use dust extraction at the work and a respirator that fits the dust. The U.S. PPE general requirements are a good starting point at OSHA 29 CFR 1910.132 — PPE general requirements, and a practical reading of how to set up and use an abrasive tool safely is at CCOHS: "Abrasive Wheels" occupational health answers.

Dust is worth its own line because it is the part people under-plan. A sanding pad throws fine dust that is easily breathed in and easily tracked to the next surface. Three things do most of the work: an extractor with the right filter for the material, the extractor actually running at the work and not parked across the bay, and a bin or bag for the waste that is not just swept to the corner. On engineered wood products and some metal primers the dust is a real long-term exposure, not just a nuisance, and the controls have to match that. The dust topic is covered plainly at abrasive dust and airborne particulates. A practical note from the floor: the first time we ran a P60 pad on a soft panel without the extractor nozzle in line, the dust landed back on the cured primer before we could wipe it, and the whole panel had to be reworked. The extractor has to be on the pad, not near it.

Cost, life and lead time

On cost, people usually buy the cheapest pad per unit and end up paying for it in machine time. A pad that runs longer and cuts evenly gives more surface per pad, so the cost per surface finished is often lower on a good grade than on a cheap one, and the difference shows up in how many panels you get between pad changes. For a job with steady volume, the wear rate and the cost per finished surface matter more than the sticker price, which is the core idea behind buying sanding pads on a 5-inch mesh sanding discs or 6-inch non-hole sanding disc basis rather than a handful at retail.

A useful way to compare two pads you are choosing between is cost per finished surface, not cost per pad. If pad A costs more but lasts three times as long over the same panel, the finished surface is cheaper on A. That is the number to ask a supplier to help you with, and it is the number that a sanding disc range conversation should be built around, because at volume the per-surface cost is where the saving actually lands.

On lead time, two things set it. In stock grits and common diameters usually ship fast; off-grid grits or a style you do not hold in the same run take longer because the paper, the grain and the bond all have to line up. For OEM or private label work, add time for the label, the packing and any spec sheet you want on the box, and the minimum order quantity is something to confirm with sales. The OEM & private-label service page explains what we can put on the packaging, and the manufacturing & quality page is where the inspection and certification process sits behind every lot you receive — that is the lot number on the pad face, and it is the record you hold if a batch question comes up later. A short note on the numbers we share: we list grit, style and diameter as standard, and we confirm maximum working speed against each model before an order ships, because that number has to come from the pad, not from a guess.

Reading the label before the pad goes on the machine

The label is where most of the mistakes get caught cheap, because it is the one place the grit, the style, the diameter and the speed all sit together. A habit that saves money on the floor is to read the whole label, not just the grit, and hold it against the four questions below before the pad touches the surface:

What grit is this, on which scale? The FEPA or ISO 848 number, and whether it matches the band you planned.
Which pad style? PSA, perforated or holeless, and does it suit the back plate and the dust load on this panel.
Which diameter? Does it sit flat on the back plate, or will the corners overhang and curl.
What speed is it made for? Confirm the pad's rated speed against the model and keep the tool below it; the label is where that number lives, not your memory.

If two of those answers disagree with the panel in front of you, the pad is the wrong one for the job, and the fix is to reach for a different grit or style, not to press harder into the one you have. For the pad styles we carry against each back plate, the sanding disc range is where to check fit, and the abrasives glossary keeps the label terms straight so you and your team are reading the same pad.

When the pad behaves badly: six failure modes

Under cutting, glazing, edge peel and clogging are the four quiet complaints, and each has a different fix. The good news is that all six start on the label, not on the pad, which means the fix is a matching change, not a replacement.

Running the tool too fast ⚡ — the corners curl and the pad peels at the edges. Drop the speed, or drop the grit, and the edge stays glued down.
Pressing instead of gliding 👆 — the face packs and the cut goes soft. The fix is lighter pressure and a moving pad, not a coarser grit.
Skipping grits ⏭️ — P60 straight to P400 leaves P60 scratches under the topcoat. Add the P120, P240 and P320 steps between and the surface clears.
Mixing pad styles on one machine 🔀 — the back plate suits one style; the pad you clamp on is made for another. The style has to match the machine, or the pad lifts at the corners and you are chasing a scratch ring that is really a fit problem.
Loading on soft material 🪵 — a grain that is as hard as the workpiece packs and stops. Move to a tougher grain, or drop a grit, and keep the pad moving rather than holding it in one spot.
Dust tracking under the pad 🌫️ — fine dust between the pad and the panel scratches the surface you just cleaned. Wipe the panel between grits and run the extractor on the pad, not across the bay.

For each of these, the hook-and-loop sanding discs page shows the style that fits a random orbital back plate, and the abrasives glossary keeps the terms straight so you and your team are diagnosing the same problem. The thread that runs through all six is that under cutting is almost always a match problem, not a bad pad; fix the grit, the style or the speed and the cut comes back.

A worked example: scratch depth and the two-coat panel

Here is the decision, worked out on a real panel, so you can see where each grit earns its place. A two-coat system on a primed door, with the goal of a clean topcoat and no scratches showing after it cures. The scratch left by a grit is what the next coat has to cover, and the coat only covers what is finer than its own depth. So the rule is: every grit you run has to be finer than the scratch the previous grit left.

Start point — P240, chosen because the door came off the primer knurled with P180 scratches. If the primer had been cut at P180, P240 is the first step that clears it; skipping straight to P400 leaves the P180 scratch showing as a shadow under the topcoat.
Middle step — P400, which closes the panel and sets a scratch band the first topcoat will sit on.
Last step — P800, which de-nibs the primer and keeps the scratch pattern uniform before the topcoat. This is where the 800 grit does the work the name promises.
After the topcoat — P1000 to P1500 on the cured paint to de-nib, then P2000 to bring the clear to a state a polish will finish.

The decision the panel forces: when you are choosing between P400 and P800 as the last step before the topcoat, the answer is P800, because the scratch it leaves is the band the topcoat follows. P400 leaves a deeper scratch that the topcoat has to fill, and on a thin coat that shows up as a dull, uneven finish. That is the whole of it: pick the grit whose scratch is the shallowest the next stage will tolerate, and stop there.

Reading the grit sequence without skipping

A skipped grit is the most expensive mistake on a panel, because it shows up under the topcoat, not on the pad. The habit that prevents it is to write the sequence down before you start, and to check the panel under raking light between steps. Raking light is the diagnostic: hold the light low across the surface and the scratch direction, and where the scratch stopped and the next one started, become visible. Two quick checks that catch a skip early:

The scratch band — if you see the previous grit's scratch showing through the current one, you skipped a step and the previous scratch is still under the surface.
The panel uniformity — if one corner of the panel shows a different scratch depth than the middle, the pad was not running flat, which is a back plate or pad style problem, not a grit problem.

For a shop that runs volume, the sequence belongs on a laminated card at each bay, because the moment the grit decision moves from the bench to memory, a step gets skipped. The woodworking sanding use notes give the sequences by species, and the request a quotation page is where a supplier confirms the exact grits a panel will run through, so the card matches the pads on the shelf.

Buying a bulk or private label pad order

When you move from buying a handful of pads to a wholesale or private label run, the conversation shifts from grit to a spec sheet. The fields that make or break an order are the ones below, and they are exactly what the OEM & private-label service page walks through in more detail.

Grain and grit — the grain (aluminium oxide, silicon carbide, ceramic) and the FEPA or ISO 848 grit, stated on the same scale you shop to.
Pad style — PSA, perforated or holeless, chosen for the machine and the dust load as above.
Diameter and back plate — the pad diameter and the plate it sits on, matched to the tool you run.
Maximum working speed — confirmed against the model, never assumed, because it has to come from the pad.
Label and packing — your logo, your part code and any spec sheet you want on the box for a private label run.
Quantity and lead time — the order quantity and how fast it needs to be on the shelf, which sets whether it ships from stock or gets made to your run.

Send those six fields and the order is a conversation instead of a gamble. The request a quotation page is where to start, and if you are new to a branded run, ask for a sample against the spec before the full order so the grit, the style and the label all match what you expect.

FAQ

What grit do I start with on a raw panel? In many cases P120 to P180 covers the first step on raw wood or a primer knockdown, then step down through P240 to P320 before you get into the finishing band. Start coarse, work down, and never jump two steps at a time.

How do I pick the right pad for my random orbital sander? Match the pad diameter to the back plate diameter, and match the style to the machine: PSA or hook-and-loop for an orbital, a perforated pad for a through-flow extractor, a holeless pad where you want a continuous sheet on a firm, steady pass. Confirm the tool's maximum speed against the pad's rated speed and run at the lower of the two.

When do I actually use P800? P800 is the last de-nib grit before the topcoat on a two-coat paint system. It clears the small defects P400 leaves and keeps the scratch pattern uniform. It is not a first pass, and on wood or laminate you commonly jump past it to P600 or P1000.

Will a 6 inch pad fit my 5 inch machine? No — the pad has to sit flat on a back plate of the same diameter. A 6 inch pad on a 5 inch plate overhangs and the corners curl, which is a scratch ring on the part and a safety issue at speed. Confirm the diameter against the back plate before you order, and keep the sanding disc range open when you are picking.

How do I know when to change the pad? Two signs: the cut has gone soft and the face looks flat and shiny instead of open, or the edges are lifting and you are getting a scratch ring on the panel. Either way the fix is the same: replace the pad and re-check the style against the back plate.

What grit standard should I name in an enquiry? Name FEPA or ISO 848 grit plus the diameter and the pad style; that keeps your order from being mixed with a different grit scale. The reference is at the FEPA grit standard.

Can I buy sanding pads on your private label? Yes — the OEM & private-label service page covers what we can put on the label and the packing, and the request a quotation form is where a bulk or branded order starts. Confirm the minimum order quantity with sales before you commit a run.

Before you buy

A short compliance and purchasing checklist. This is a reminder, not a substitute for your own site rules, and in compliant use with the right protection the risk of these tools is reduced but not zero.

Confirm your tool's maximum speed is below the pad's rated maximum working speed before every use; that figure comes from the pad maker, so confirm it against the model.
Match the pad diameter to the back plate diameter, and use a pad style (PSA, perforated or holeless) that the machine is built to run.
Fit and keep the tool guard on at all times, and check the pad sits flat with no corners lifting.
Wear eye and face protection, and use dust extraction at the work with a respirator that suits the dust load for the material.
Confirm the grit, the pad style, the diameter and the grit standard (FEPA or ISO 848) in every order so you do not mix scales.
Ask for the inspection record or certificate against the lot number you are buying; that is the record a request a quotation conversation should carry.
Store pads dry and away from heat, and keep the grits separated by band so a P60 does not find its way into a P400 drawer.
Follow the pad maker's install notes, and on a soft panel check the surface for heat and scratch depth between grit steps.

If you tell us the material, the finish you are aiming for and the sander you run, we can help you pick the grit band and the pad style to start from. Send the three and we will work the sequence with you on the request a quotation page.