Abrasive Backing Materials

Designations, weights and uses of the most common paper, cloth and fiber backing materials for sandpaper and abrasive belts and discs.

Weight of backing material

A lighter, more flexible backing is used for sanding irregular contours and a heavier, stiffer backing is better for flat or regularly rounded contours.

Paper backings

Listed in order from lightest to heaviest weight:

A - A very light weight (40 lb) paper - typically used for fine grain finishing paper and for light PSA or hook & loop discs

B - A light weight (60 lb) paper- typically used for fine grain finishing paper and for light PSA or hook & loop discs

C - A medium weight paper - typically used for sheet sandpapers and light PSA or hook & loop discs

D - A medium to heavy weight paper - typically used for sheet sandpapers and PSA or hook & loop discs

E - A heavy weight paper - typically used for stroke or wide belt sanding belts

F - A very heavy weight paper - typically used for stroke or wide belt sanding belts

Cloth backings

Listed in order from most to least flexible:

J - A light weight, flexible Egyptian cotton cloth

JF - A light weight, very flexible Egyptian cotton cloth

X - A heavy, stiff Egyptian cotton cloth

XF - A heavy, yet flexible Egyptian cotton cloth

YX - A lighter weight polyester backing

YY - A very heavy, stiff polyester backing

Fiber

Fiber is a very hard, strong, coated abrasive backing material consisting of multiple plies of chemically-impregnated paper. Used primarily for disc products.

Bonds

Hide glue is sometimes used to bond the abrasive to the backing but is not heat and water proof. Wet/Dry sandpapers use a resin adhesive and a waterproof backing.

Open coat

A sandpaper in which the abrasive grain covers approximately 50% to 70% of the coated surface is called open coat. An open coat helps to retard loading of sticky or gummy materials such as softwoods or paint.

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