As professional French Polishers, we use sandpaper on a daily basis. We are often asked about the different types of sandpaper and when to use them, and have put together some tips for you in this blog article. Following these guidelines should help you get the best results when working with wood.
How does sandpaper work?
Sandpaper is made up of a number of small particles with sharp edges that cut the wood the same way a saw blade or chisel does. Because of the way sandpaper is constructed, it is ideal for smoothing down edges and refining pieces of wood. Unfortunately, unlike other tools, sandpaper cannot be sharpened and does become inefficient after it is used for some time.
Is all sandpaper the same?
No. Sandpaper comes in a variety of grits and grades. Commercial grade sandpaper is commonly available at hardware and DIY stores and is most commonly used by individuals who are working by hand. The industrial grade sandpaper is usually only available through trade shops because it contains a higher quality of abrasive grit, backing material and bonding agent and is designed to be used on production lines.
What about the different grits?
Sandpaper is identified by a grit number, which is the number of abrasive particles per inch of sandpaper. The lower the grit, the rougher the sandpaper, and the grit you use really depends on what you are trying to do with the wood. Because each project has different requirements, we’ve put together this table to help you decide which sandpaper is best for you. Our French Polishers recommend sanding with progressively finer grits because this removes scratches faster and leaves a smooth finish than using just one grit.
Grit Grade guide
40-60
Coarse. Often used for the first stage of sanding. This paper is ideal for heavy sanding and stripping, or roughing up the surface of the wood.
80-120
Medium. This grit helps to smooth the surface of the wood and remove small imperfections or marks.
150-180
Fine. Often used for the final phase of sanding before the wood is finished with a sealer or stain.
220-240
Very Fine. Used for sanding between coats of stain or sealer.
280-320
Extra Fine. Helps to removing dust spots or small marks between coats of finish.
360-600
Super Fine. Used to remove some luster or surface blemishes and scratches on the final coat of finish.
For most projects, you can stop sanding at 150 or 180-grit, but if you plan to use a water-based stain then we recommend sanding up to a 200-grit sandpaper. This is because water-based stains tend to magnify a scratches and finer sandpaper can help remove more of them. Be aware that if you sand with super fine sandpaper, you can end up sealing off the grain and prevent finishes from penetrating, so it is important to know which sandpaper to use at each stage of a project.
Dry versus wet
Sandpaper comes in dry and wet varieties. Dry sandpaper is used on wood, metal and plaster, and works well in repairing floors, furniture, and walls. Wet sandpaper is more often used on metal and fibreglass surfaces.
Different types of abrasives
Sandpaper comes in five different abrasives but not all are ideal for wood. Glasspaper, for example, is very lightweight, and disintegrates easily, so it is not usually used for woodworking. Garnet paper, on the other hand, is more commonly used on wood. Keep in mind that although it leaves a better finish, it does not sand as quickly as other abrasives so it is usually used for the final stages of sanding.
Aluminum Oxide is commonly used for wood projects. It is more durable than Garnet paper, but doesn’t leave as smooth of a finish. It is often used in power sanders. Silicon Carbide paper is used primarily for finishing metals or for wet-sanding. It is not typically used on wood.
Ceramic paper is often used for belt sanders, but sometimes is used for hand shaping wood. It will usually leave a very rough finish, so be careful when using it on plywood and veneers, because it can quickly sand through the finish layer and ruin all your hard work.
French polishers’ services for all your wood
If you have any questions about sandpaper, please contact our French Polishers today and we will try to answer your questions in another blog. For more information on our French Polishing services, please speak to a member of our team on01827 874 535.