Sandpaper is essential in finishing a woodworking project. The surface of a well-crafted woodworking object does not show any scratches, dings or dents in the wood. The stain and sealant will emphasize any small defect in the wood. It is very important to look the project over completely before staining. Use a bright light to inspect the project prior to applying stain and finish.
Sandpaper is sold in numerous abrasive grits and type of backing. Sandpaper of the past was made from tiny granules of stone such as flint or garnet. The stones were ground to a find grit and glued onto a paper surface. Today, most sandpaper is made with man-made abrasives such as aluminum oxide or silicon carbide. These materials last longer than stone granules. The man-made abrasives are very hard and sharp. The material is glued onto the surface of paper or cloth.
Sandpaper is sold for hand sanding and for use on electric sanders. Sandpaper used on electric sanders normally has a fabric backing to make the sandpaper more durable. Paper backed sandpaper is used for hand sanding. The back material weight determines the durability of the sandpaper.
Labels on paper backed sandpaper begin with the letter “A” and go through the letter “F.” “A” is the finest sandpaper with “F” being the courses. Cloth backed sandpaper labeling includes: “J” – the lightest and most flexible, “X,” “Y,” “T,” and “M” the heaviest and least flexible. The sandpaper sold for belt sanders is an “X” weight cloth backing.
Cut sheets of sandpaper are used for hand sanding and on any clamp type electrical sander. There is not much choice in sandpaper when it comes to using sandpaper on clamp style electrical sanders. All the sandpaper is paper backed. The sandpaper wears out quickly and tears easily especially when using the fine grit sandpaper.
Another classification for sandpaper is called the “grit”. Grit refers to the amount of granules per inch on a piece of sandpaper. Sandpaper is sold in grit sizes from 40 to 600. Sandpaper classified as 40 grit is very coarse and 600 grit sandpaper is very fine.
There is a type of sandpaper that is called a coated abrasive. Two types of coated abrasives are available for purchase. They are open-coat and closed-coat. An open-coat piece of sandpaper has voids or open spaces in-between the abrasive. A closed-coat surface has no voids or openings between the abrasive. It has a solid coated surface.
Use a closed-coated sandpaper whenever possible. This type of sandpaper allows for a faster completion of sanding a wood surface. Certain woods will cause the abrasive surface to clog. In this case, an open-coat sandpaper is the better choice for the project. A special white or gray sandpaper is available that is a closed-coated abrasive. This sandpaper is designed specifically to not clog while sanding. It has the special name of stearate paper.
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