Abrasive Sanding Discs

The sanding disc is a circular abrasive disc that is attached to power sanders or other tools to remove material, light defects, corrosion, paint, and rust from wood, metal, and plastic surfaces. The hook and loop sanding discs and PSA abrasive discs are commonly used and come with different grits, holes, coated grains, backings, and colors. Fastplus is constantly adding more sanding discs into product lines, below is a short buying guide of our sanding discs to help buy the right one for your work.

The sanding discs can be divided into 2 types from the mounting features: One is the hook and loop (velcro) sanding discs, and the other is quick change and PSA/adhesive-backed abrasive discs.

Hook & Loop Sanding Discs: Backed with hook and loop (velcro) system, which allows sanding discs can be attached firmly and removed quickly for better efficiency.
Standard sizes: 125mm, 150mm / 5”, 6”
Holes/ Perforation: No hole, 6/8/9/15/17/multi-holes
Abrasive types: Aluminum oxide, Zirconia alumina, Ceramic
Coating Types: Open coat, semi-open coat, closed coat
Compatible tools: Random orbital sanders, disc sanders or handheld rotary tools.
Common uses: Sanding wood, fiberglass, metal, paint and plastic surfaces

PSA Sanding Discs: Backed with Pressure Sensitive Adhesive (PSA), this kind of self-adhesive abrasive disc can be mounted to the sanding tools easily and quickly. PSA discs are generally made with cloth or paper backing, cloth backed sanding discs are used for heavy-duty sanding, and paper-backed PSA discs are featured as more affordable and lightweight and used for light sanding tasks.
Standard sizes: 125mm, 150mm / 5”, 6”
Holes/ Perforation: No hole
Abrasive Types: Aluminum oxide, Zirconia alumina, Ceramic
Coating Types: semi-open coat, closed coat
Compatible tools: Random orbital sanders, disc sanders, bench sanders, platen disc sanders
Common uses: Grinding, Sanding and finishing of wood, fiberglass, metal, paint and plastic surfaces

Other types of discs: Film Sanding Discs, net/mesh abrasive discs, scuff discs and superfine sanding discs

Distinguishing sandpaper grit sizes is important because not every project requires the same.
In the United States, grit is determined based on a gradation scale established by the Coated Abrasive Manufacturers Institute (CAMI). When shopping for sandpaper, you’ll see numbers such as 80-grit, 100-grit, or 200-grit. Keep in mind:

The higher the number, the smaller the grains and the finer the sandpaper grit.
And, conversely, lower numbers indicate larger grains and overall coarser sandpaper.

On the CAMI scale, sandpaper grit is measured in microns, and to get an idea of how small a micron is, check out a piece of 100-grit sandpaper. The small grains on the sandpaper measure approximately 141 microns in size, which is equivalent to .00550 of an inch. Very small.

Most sandpaper you buy at DIY centers and lumberyards will bear the CAMI scale, but if you order sandpaper online, you may run across sandpaper grit sized by the Federation of European Producers of Abrasives (FEPA). Grit sized with the FEPA scale is indicated by the letter “P” preceding the grit number. While there are too many grit gradations to list, if you’re buying FEPA-sized sandpaper, the following commonly used CAMI sizes will give you an idea of the corresponding FEPA sizes. FEPA sizes are not an identical match to CAMI sizes, but you can get something very close by selecting one of the two closest FEPA numbers.

40-grit (CAMI) sandpaper corresponds closely to (FEPA) P-36 or P-40
80-grit (CAMI) sandpaper corresponds closely to (FEPA) P-80 or F-100
100-grit (CAMI) sandpaper corresponds closely to (FEPA) P-100 or P-120
120-grit (CAMI) sandpaper corresponds closely to (FEPA) P-120 or P-150
220-grit (CAMI) sandpaper corresponds closely to (FEPA) P-180 or P-220
400-grit (CAMI) sandpaper corresponds closely to (FEPA) P-600 or P-800

Generally, the following can be a guide to select the right grit size of sanding discs or sandpapers:
P40 For removing thick layers of rust and lacquer.
P60 For pre-treating unprocessed surfaces.
P80 For correcting heavy areas of unevenness.
P120 For roughening before priming or pickling.
P180 For initial sanding after priming.
P240 For initial wet sanding after priming.
P400 For smoothing filled surfaces.
P600 For fine sanding before painting.
P1000 For final fine sanding before painting.
P1200 For final fine sanding before painting.
P2000 For final fine sanding before painting.