Sandpaper is made by bonding an abrasive grain like aluminum oxide, garnet or silicon carbide to a backing material. It is used to remove material from surfaces, either to make them smoother, to remove a layer of a substance like paint, or to make the surface rougher. The type and size of grain, the type of adhesive and the type of backing material all have an effect on the suitability of sandpaper for a particular job.
Abrasive paper works a lot like any other cutting tool, just on a smaller scale. The particles used to make sandpaper have a number of sharp edges that cut or shave away the material the same way a saw blade does.
Aluminum oxide, silicon carbide and garnet are the three major types of sandpaper on the market.
Aluminum oxide is a man-made material which is one of the most common woodworking abrasives. Aluminum oxide is a good all-surface general purpose sanding grain. Aluminum oxide cuts faster and lasts longer than garnet.
Garnet is a natural mineral that is an excellent abrasive for general wood sanding. Garnet produces a finer and softer scratch pattern and is often used for final sanding. Garnet also has the tendency to seal off a wood’s grain, which allows pigmented stains to penetrate certain woods more evenly.
Silicon carbide is suitable for both wet and dry sanding and is also known as ‘waterproof’ paper. Silicon carbide is good for sanding hard materials such as stone, porcelain and glass. Silicon carbide is fast-cutting and almost as hard as diamond. Silicon carbide is greatly used during automotive painting and repair.
Grit is the number of abrasive grain particles per inch of sandpaper. The lower the grit, the bigger the grain and the coarser the sandpaper. Higher grit sandpaper has smaller grains. This means that it takes more grains to fill up a square inch, which helps give the sandpaper a smoother feel.
Be sure to take all appropriate safety precautions, especially when power sanding. You should always refer to the power tool manufacturer's instructions.
It is best to use progressively finer grits of sandpaper until you get the desired finish. This way each progressive grit of sandpaper removes the scratches from the previous grit. Skipping grits to save time will often have you sanding longer.
Be sure not to use excessive pressure when you sand, let the abrasive grit do the work. Using excessive pressure will only clog the paper or cause the paper to wear out much more quickly.
When sanding wood, sand along the grain, not across it. On a smooth, non-grained surface, move the sandpaper in small circular motions.
Open-coat means that there is space in between the particles that make up the sandpaper. This helps prevent clogging by giving the material that you are working on a place to go.
Closed-coat means there is little or no space in between the particles. Closed-coat is used more with sanding metal and some wood finishes and has a tendency to easily clog.
Sandpaper has many types of backing material. This includes paper, cloth and fiber. Paper backing is most commonly used material for hand sanding. Cloth backing is more durable than paper and is better at bending and flexing and is mostly used with power tool abrasives. Fiber backing, which is very hard and strong, is used for resin bonded fiber discs.
The weight of the backing is usually designated by a letter. For paper, the letters range from A to F, with A being the lightest and F the heaviest. Letter classification is different for cloth, with the weight of the backing being, from lightest to heaviest: J, X, Y, T and M.
Use this handy chart below to get an approximate equivalent to metric sizes.
What is Gold Flex?
What is Red Flex?
What is Stearate?
Can I use Gator Finishing Products sandpaper with water?
How can I extend the life of my sanding belt? An abrasive belt cleaning stick cleans off dust particles and lubricates to minimize dust collection. The belt cleaning stick can also extend the life of sanding disc and drums.
Where can I purchase Gator Finishing Products?