3M Cubitron II Net Disc Roll 6 in. P80+ 50-Pack | THR-31650

3M Cubitron II Net Disc Roll – 6 in. / P80+ / 50-Pack

Part Information

• Part Number: 31650 / THR-31650
• Brand: 3M
• Product Line: Cubitron II Net Abrasive
• Official Product Type: Net Abrasive Disc Roll
• Diameter: 150 mm (6 in.)
• Grade: 80+ (P80-class)
• Quantity: 50 discs per roll
• 3M ID: 60455118194
• UPC: 00051131316508
• Weight: Approx. 0.7 kg (1.5 lb) per roll

What This Product Does

The 3M Cubitron II Net Disc Roll 31650 is a 6 in. / 150 mm P80+ abrasive disc roll designed for aggressive material removal with highly efficient dust extraction. Unlike conventional abrasive discs, Cubitron II uses precision-shaped ceramic abrasive grain that cuts into the work surface rather than plowing across it, producing faster cutting speeds, lower heat generation, and longer disc life compared to standard mineral abrasives.

The net-style abrasive construction allows dust to pass through the full sanding surface rather than relying on a fixed hole pattern, making it particularly effective with vacuum-assisted sanding systems. At P80+, this disc is at the aggressive end of the Cubitron II Net range — suited to initial shaping, stripping, and fairing work before stepping up to finer grades.

Intended Applications

• Marine fiberglass and composite surface preparation
• Gelcoat and paint removal
• Fairing compound initial sanding
• Primer and substrate preparation
• Body filler shaping
• General aggressive surface leveling
• Automotive refinishing preparation
• Wood and composite sanding where P80+ is appropriate

Grade Selection Guide – 6 in. Cubitron II Net Disc Roll Family

• 31650 – 80+ (this product – aggressive removal / fairing)
• 31651 – 120+ (intermediate shaping)
• 31652 – 150+ (medium finish)
• 31653 – 180+ (fine finish)
• 31654 – 220+ (very fine)
• 31655 – 240+ (finishing)
• 31656 – 320+ (final preparation)

Match both diameter (150 mm / 6 in.) and abrasive grade before ordering. These rolls are not interchangeable by grade.

When to Replace

• Cutting speed noticeably decreases during use
• Abrasive surface becomes loaded with sanding debris
• Disc is torn or physically damaged
• Attachment surface no longer holds securely to the backup pad
• Edge damage begins affecting finish quality

Usage Notes

Use with a compatible 6 in. Hookit-style backup pad and a vacuum or dust-extraction sander. For best results:

• Keep the backup pad surface clean and free of debris
• Align the disc fully with the pad before use
• Connect the sander to an effective dust-extraction system to take full advantage of the net construction
• Allow the abrasive to do the work — avoid excessive downward pressure, which can reduce disc life and finish quality
• Use a hook saver or interface pad where appropriate to extend backup pad life

Technical FAQ

Q: What is the difference between Cubitron II Net and standard Hookit discs?
A: The net construction allows dust extraction across the entire disc surface rather than through a fixed hole pattern. This results in more consistent dust removal, cooler cutting, and better surface visibility during sanding. It requires a compatible vacuum-assisted sander for full benefit.

Q: Is P80+ the same as P80?
A: The 80+ designation is 3M’s official grade marking for this disc, indicating performance equivalent to or exceeding a P80 conventional abrasive. In practice it cuts aggressively at the P80 level and is used in the same applications.

Q: What backup pad size is required?
A: A 6 in. / 150 mm Hookit-compatible backup pad is required. Confirm your sander accepts 6 in. Hookit-style discs before ordering.

Alternate Part Numbers

• 3M 31650
• THR-31650
• 3M ID 60455118194
• UPC 00051131316508

Parts Desk Insights

This disc comes up most often in fiberglass and fairing work — 80+ is the right starting point for initial material removal and fairing compound shaping before stepping to 120+ or 150+ for progressive finishing. The most common ordering issue is customers mixing up the grade numbers within the 31650–31656 family, so it’s worth confirming the grade alongside the diameter before placing an order. The net construction only delivers its full dust-extraction advantage when used with a properly connected vacuum system — running it without extraction works, but the disc will load faster and cut speed will drop sooner.