By Martin Hart on Thu 05 March 2020
Whether a gleaming oak floor or a smoothly painted and finished wall- these finishes are made possible by the application of sandpaper. Choosing the right sandpaper and using it correctly is perhaps one of the most important tools and methods to finishing furniture, brightening brass, removing rust, smoothing any wooden project and much more.
Even though it is a task many of us wish we cut either avoid or cut shorter, it is a key tool to avoid any imperfections, which otherwise will be magnified when the final finish coat is applied.
For every sanding chore, there is a suitable paper…Choosing the Right Grit
Sandpaper is usually based on a number of abrasive particles per square inch of the paper with the lower the number meaning the coarser the grit on the paper will be. They are commonly graded as:
• Coarse- 40-60
• Medium 80-120
• Fine- 150-180
• Very Fine- 220-240
• Extra Fine- 280-320
• Super Fine – 360 +
Many people presume that they can use a super fine sandpaper for anything. There is nothing saying you can’t and it isn’t the incorrect method, but coarse grit papers will remove material quicker and when followed by finer grit papers, make for a much easier and quicker sanding. Any experienced woodworker will tell any beginner, the quicker you can get through sanding, the better.
Top Tip: When you really want a smooth finish, begin with the coarser paper and work your way up the finer grits. After a varnish, step up to 150 + grit then a 220+, and between coats of new finish, use a 400 grit.
What Grade of Sandpaper?
There are generally two different grades of sandpaper: commercial and industrial. The differences are mainly the material used as the grit, the backing paper and the glue used to hold the grit.
Industrial grades of sandpaper are much better quality for all above factors. In addition to this, you may have noticed two different types, either rated as open coat or closed coat. The difference between these is that closed coat has closer grouped grit particles, whereas open coat has larger gaps between them.
Top Tip: Open coat sandpaper is better for woodworking, as it clogs less often especially when the project involves softwoods.
Type of Abrasives
There are five main types of sandpaper available, which are as follows:
• Glass paper- This is also known as flint paper. It is lightweight and usually a pale yellow, it disintegrates easily so is rarely used for wood working.
• Garnet Paper – This is usually a brown/red colour and is more commonly used in wood working. It doesn’t sand wood as quickly as other sandpapers may do, but it leaves a smoother finish. Choose this for finish sanding.
• Aluminium Oxide – Great for woodworking projects although is more commonly used in power sanders. This paper is more durable than garnet but still doesn’t leave as smooth of a finish.
• Silicon Carbide- This paper which is dark grey or black is used primarily for either finishing metals or wet sanding using a water lubricant. It is not usually used for wood work.
• Ceramic Paper- Ceramic sandpaper is made up from the most durable abrasives and can get rid of considerable amounts of most materials quickly. It is often used in a sanding belt but sometimes used for hand shaping of wood. It can sometimes leave a rough finish so take care when using, particularly with veneers or plywood.
Tips for Which Sandpaper to Use for Which Job
40 Grit- Used for removing layers of paint or varnish from rough timber 60 Grit- Removing layers of paint or varnish or sand down surfaces that don’t have as many layers 80 Grit- Use after 60 grit to sand uneven edges or remove deep scratches in timber or board.
100-120- Useful for sanding down plastered walls, painted surfaces and to sand over surfaces previously used 60 or 80 grit. 150-180- Useful for after using 100-120 grit and to de gloss any surface before applying paint
240 grit- Ideal for sanding between coats of varnish or paint. This grit of sandpaper will not damage any finish if used with a sander either.
320-400 - Can be used wet or dry and is great for polishing.
600+ - Normally used wet, it is great for polishing painting surfaces for a smoother appearance and finish.
If you would like any more information regarding our sandpaper products and sanding belts and disks, you can browse our online range or get in touch with our friendly team who would be more than happy to advise you on the best product for your project.