Mirka Coarse Cut 5-in. P40 PSA Sanding Disc for Coarse Sanding (40-332-040)

The Mirka 40-332-040 Coarse Cut PSA Disc, 5 Inch is a heavy-cut sanding disc for aggressive stock removal on demanding surface prep jobs. This is a sanding disc designed for coarse sanding, stripping, and leveling work on materials like lacquer, putty, glass-reinforced polyester, and weld seams. Model Number: 40-332-040. If you need to remove material quickly instead of creeping up on it with a fine grit disc, this is the kind of abrasive that makes sense.

What matters here is the cut rate. With a 40 grit abrasive, this disc is meant for the early stage of sanding where the goal is fast removal, not finish-ready results. That makes it a practical choice for body filler shaping, weld cleanup, and rough prep before moving to finer grits. Mirka calls this Coarse Cut for a reason: it is built to be aggressive and productive on jobs where slower abrasives just burn time.

The abrasive material is aluminum oxide, which is a proven choice for general-purpose sanding and coarse surface prep. Mirka also backs this disc with reinforced construction and its Progressive Bond technology, which is meant to improve durability under hard use. In plain terms, that matters because coarse discs often fail at the edge first. When the edge breaks down too early, you get inconsistent cutting and deeper scratch patterns that create more cleanup later.

Another practical advantage is reduced clogging. On fillers, coatings, and similar materials, loading can kill sanding speed fast. A disc that resists clogging stays useful longer and keeps the cut more consistent through the job. Mirka also notes flexibility on rounded surfaces, which makes this disc more useful beyond flat panel work when you’re blending curves or contouring repairs.

The 5 inch format fits a common class of sanding setups, and the PSA backing is important if your sander or pad is designed around adhesive-backed discs rather than hook and loop. That secure attachment helps during hard sanding passes where you do not want the disc shifting. Just make sure your tool or backup pad is set up for PSA discs before ordering.

This sanding disc makes the most sense for auto body work, metalworking, composite repair, and general surface prep where heavy removal comes first. Serious DIY users can absolutely use it, but it is best suited to buyers who understand grit progression and need a true coarse-cut abrasive rather than an all-around finishing disc. If your job starts ugly and needs to get flat in a hurry, this Mirka disc is aimed right at that stage.

Mirka 40-332-040 Coarse Cut PSA Disc, 5 Inch Gets Right to Work

This is the kind of sanding disc you buy when you need removal speed first and finish quality later.

• Who it’s for: Auto body techs, metal fabricators, composite repair users, and serious DIYers doing rough prep and shaping work.
• Why it stands out: The coarse P40 cut, aluminum oxide abrasive, reinforced build, and PSA backing make it a practical choice for hard sanding where cheap discs fall apart early.
• Worth knowing: This is not a finishing abrasive, and it is only the right choice if your pad accepts PSA discs.

• What kind of sanding is this disc made for? It is made for coarse sanding and aggressive material removal, including lacquer, putty, glass-reinforced polyester, and weld seams.
• What grit is it? This disc is P40, which is a very coarse grit used for early-stage shaping and stripping work.
• Is this a hook and loop sanding disc? No. The product data identifies it as a PSA disc, which means it uses pressure-sensitive adhesive backing.
• What size sander does it fit? It is a 5 inch disc, so it fits compatible 5 inch sanding pads and sanders designed for PSA discs.