Difference Between 120 & 150 Sandpaper

120 Sandpaper

• 120 sandpaper is classed as a "macrogrit" but is more commonly known as a fine sandpaper. This means that it is used for sanding bare wood in preparation for painting, varnishing or finishing. This grade is not suitable for removing paint, varnish or cleaning any water stains or plaster.

150 Sandpaper

• 150 sandpaper is even finer than 120 sandpaper and is classed as very fine. This sandpaper would be used to sand bare wood after using the 120 grade. A 120 grade would used to remove small imperfections and marks and then a 150 grade is passed over the bare wood, to apply a final, softer appearance before finishing the wood.

Main Components of Sandpaper

• The three main components of sandpaper are the abrasive grit, the backing material and the bonding agent. The abrasive grit is the material applied to the backing material, that will actually achieve the abrasion. The backing material is simply the heavy duty paper to which the grit is fixed using a strong bonding agent.

Difference Between Industrial and Commercial Grades

• Industrial grade sandpaper will feature a grit material that is very hardy and unlikely to wear out or break down after continuous use. By contrast, commercial sandpaper uses an inexpensive grit and a weaker paper. Industrial sandpaper will often use a fine cotton or polyester as backing material and phenolic resin to bond the grit. The commercial bonding material is most likely a low-grade glue.