Collected Information on Abrasive Paper Backings

There are many kinds of sandpaper on the market and while the materials they are made from and the grit sizes are widely described, the designations for backing weights are a bit harder to find. This led me to search for information related to bonded abrasives so that I would know what I was buying from catalogs.

The best overview I've found describing the varieties of sandpaper and their use is Mirka's document Effective Wood Sanding. There are also good technical descriptions of sandpaper at AAAbrasives and Sandpaper Lot that are identical to each other. Chapter 10 of the book Deburring and Edge Finishing Handbook by LaRoux K. Gillespie has a section on Bonded Abrasives with useful information. I compiled the following information on backing weights from these sources.

Paper backing weights

  • A-weight (40 lb) - Lightweight and flexible, primarily used for hand sanding and finishing operations
  • B-weight (60 lb) - Medium-lightweight for fine through intermediate hand and power sanding
  • C-weight (70 lb) - Light-medium weight for fine through intermediate hand and power sanding
  • D-weight (90 lb) - Medium weight for coarse through intermediate hand and power sanding
  • E-weight (130 lb) - Heavy weight used where tearing resistance is important in belts, discs, and rolls, and for very coarse sanding sheets
  • F-weight (165 lb) - Strongest and least flexible paper backing primarily used in industrial applications

Cotton and synthetic cloth backings are more durable than paper and are available in the following weights

  • F-weight (flexible cloth) - Highly flexible, lightweight jeans cloth, used when extreme flexibility is desired
  • J-weight (Jeans) - Lightweight and flexible, used for finishing and on contoured surfaces
  • X-weight (Drills) - Stiffer backing, used for coarse and fine grit sanding and for sanding belts
  • Y-weight (Heavy Drills) - Stiff and strong, used for severe applications such as heavy duty belt sanding
  • H-weight (Heavy Duty) - Strongest and heaviest cloth backing, used only in extreme applications
  • S-weight (Sateen) - Heavy duty stretch resistant backing, used in specialized applications