80 vs 120 Grit Sanding Discs: Which One Should You Buy?

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Below: what the grit numbers mean, the discs covered in this guide, how to choose between the two grits, and how dust extraction and disc fit change the result.

80 vs 120 grit sanding discs: what the numbers mean

The POTUINOM listing states a grit range that frames the whole choice: 40-100 grit is coarse grit for rough processing, 120-320 grit is for conventional polishing, and 400-2000 grit is for grit polishing. On that scale, 80 grit sits in the coarse band, and 120 grit sits at the start of the conventional polishing range. That is why the two grits do different jobs even though both look like ordinary sandpaper at a glance.

Use 80 grit when the surface still needs shaping: removing paint, grinding metal, or clearing rust. The Serious Grit listing names paint removal and auto body work, the POTUINOM listing names grinding, polishing and derusting, and the TPmax listing names grinding, polishing and rust removal. Use 120 grit when the rough work is done and the surface needs refining for the next step, such as a smoother base for paint or a cleaner finish after a coarse pass.

Match the grit to the stage, and change discs when the job changes, rather than forcing a single grit through every pass.

The discs in this guide, ranked

The four discs covered here are all in the 80-grit range: two are listed as 80 grit, one as 80-plus, and one as P80. They show what the coarse side of the choice looks like in real packs, while 120 grit is the finer step described in the range note above. The ranking below weighs body-work fit, dust handling, and pack size.

1. Serious Grit 6-inch discs. The Serious Grit discs are 6-inch, 49-hole, P80 grit discs in a 50 pack, made with a polyester film backing and an aluminum oxide abrasive grain. The listing states that they fit Festool 150 series ETS and Rotex random orbital sanders with 6-inch pads, and that the film construction resists tearing around corners. A heat-treated zinc stearate anti-clog coating sheds dust before it clogs the disc, and the discs are wet and dry, for auto body work including paint removal and wet sanding. For body work, that combination of a larger pad, a film backing, and wet sanding puts this pack first.

2. 3M Xtract Net Disc 710W. The 3M disc is a 5-inch, 80-plus grit net disc in a 50 pack, with a hook-and-loop backing for random orbital sanders and hand sanding. The listing states that the net backing allows dust extraction of up to 99 percent, for a virtually dust-free work environment, and that the precision-shaped grain fractures into sharp cutting edges for twice the abrasion life and cut rate of leading competitor net discs. Recommended uses in the listing include woodworking, composite sanding, metal fabrication, primer sanding, and gelcoat sanding. For a shop that values dust control, this disc ranks second.

3. POTUINOM 100-disc set. The POTUINOM set holds 100 discs at 5 inches with an 8-hole pattern and a thickened hook-and-loop back, made with aluminum oxide abrasives. The listing states that the discs suit most 5-inch random orbital sanders, including die grinders, air grinders, and electric drills, and that they suit grinding, polishing and derusting of metal, non-metal, wood, rubber, leather, plastic, stone, and glass. The 8-hole pattern removes dust during sanding, which helps keep the workspace clean. With a large pack and a broad material range, this set ranks third.

4. TPmax 100-disc set. The TPmax set holds 100 discs at 5 inches, or 125mm, with an 8-hole pattern, a gold coating, and aluminum oxide abrasives. The listing states that the hook-and-loop backing gives quick and firm attachment, that the 8-hole pattern supports efficient dust extraction and less clogging, and that the discs suit wood, metal, automotive, rubber, leather, plastic, stone, and glass. They fit 125mm random orbital sanders, and the listing names grinding, polishing, and rust removal. This set ranks fourth on the same coarse-grit job, with a large pack and a simple 8-hole design.

How to choose between 80 and 120 grit

Start from the surface in front of you, not from the grit on the shelf. If paint needs removal or rust needs clearing, start at 80 grit. If the surface is already level and even, and the goal is a smoother base for paint or a cleaner finish, move to 120 grit for conventional polishing. Changing grit as the surface improves beats running a single grit through a job that has moved on.

• Check the stage. Rough processing calls for 80 grit. Conventional polishing calls for 120 grit.
• Check the pad size. The discs in this guide are 5-inch or 6-inch discs, so match the disc to the pad on the sander.
• Check the hole pattern. An 8-hole disc, a 49-hole disc, and a net disc all handle dust differently, so match the pattern to the pad and to the dust collection in use.
• Check the backing. All four discs in this guide use a hook-and-loop backing, which allows quick disc changes.

Dust extraction and disc fit

Dust extraction is the practical difference between the packs, after grit. The POTUINOM and TPmax discs use an 8-hole pattern that the listings link to efficient dust extraction and less clogging. The Serious Grit discs use a 49-hole pattern with an anti-clog coating, and the listing states that the discs stay virtually dust free when paired with a vacuum or dust collection system. The 3M disc uses a net backing instead of holes, and the listing states dust extraction of up to 99 percent.

Fit matters as much as dust handling. The POTUINOM, 3M, and TPmax discs are 5-inch discs, while the Serious Grit discs are 6-inch discs for 6-inch pads. A disc that does not match the pad can overhang or sit unevenly, and a hole pattern that does not match the pad pulls less dust through the pad. Read the pad size on the sander, then pick the disc size and hole pattern to match, before opening a pack.

FAQ: garage tools

Is 80 grit too coarse for paint prep?

80 grit is coarse grit for rough processing, so it suits removal and leveling before paint prep, rather than the final pass. Remove paint and clear rust at 80 grit, then move to 120 grit for conventional polishing and a smoother base for paint.

When should I switch from 80 grit to 120 grit?

Switch when the surface is level and even, and the rough work is done. At that point the job changes from shaping the surface to refining it, and 120 grit, at the start of the conventional polishing range, fits that stage.

Do 5-inch and 6-inch discs fit the same sander?

Not on the same pad. Match the disc to the pad size on the sander. The POTUINOM, 3M, and TPmax discs in this guide are 5-inch discs, and the Serious Grit discs are 6-inch discs for 6-inch pads, including Festool 150 series sanders with 6-inch pads.

What does an 8-hole disc do?

An 8-hole disc lets dust pass through the disc during sanding, which supports efficient dust extraction and less clogging. The POTUINOM and TPmax discs in this guide use an 8-hole pattern, and both listings link that pattern to a cleaner work environment.

Can I use these discs wet?

The Serious Grit discs are wet and dry film discs, and the listing names wet sanding for auto body work. Wet use is Not stated for the POTUINOM, 3M, and TPmax discs in this guide, so follow the listing for each disc and the sander manual for wet work.

Related: sanding discs for auto body, sanding discs for paint prep, and 6-inch sanding discs.