Abrasives

Early kinds of abrasive

• Sand paper was first mass-produced in 1833.

Early kinds of abrasive

• Early sand paper used tiny glass shards bonded to paper.

Today’s common types of sand paper

• Garnet: common for wood working.

• Aluminum oxide: for wood or metal.

• Silicon carbide: wet or dry applications

Garnet Aluminum oxide Silicon Carbide

Grit size

The number on the back of the sand paper refers to the number of grains that fit in a square inch.

Coarse Smooth

80 100 120 150 180 220 320

The larger the number the smaller the grit size.

The smaller the number the larger the grit size.

Use coarse paper for rough sanding

80 to 100 grit

• For heavy sanding.

• To remove machine marks.

Use medium grit for final sanding of wood.

120, 150, 180 grit

• Breaking edges

• Removal of scratches

Use Fine grit for sanding between coats of finish.220, 320 grit

• Sand lightly between coats of finish.

• Remove any rough areas of finish.

Types of sanders

• Portable belt sander.– For aggressive or rough sanding

Types of sanders

• Orbital sanders, ½ and ¼ sheet– For medium to fine sanding

Types of sanders

• Random orbit, Pneumatic and electric.– For swirl free sanding of wood .

Types of sanders

Stationary• Wide belt sander

– For sanding machine marks out of surface of wood.

Types of sandersStationary

• Edge belt sander – For straight edges of boards and radiuses.

Use caution, this machine can remove material quickly

Types of sandersStationary

• Disc Sander– For outside curves and short straight edges.

Types of sandersStationary

• Oscillating spindle sander – For inside curves or radiuses.