What types of sandpaper are there? Which grain is suitable? What is ideal for wood, metal or any other use? Here we explain to you
Sandpaper is a basic material in a multitude of jobs in which it is necessary to smooth and / or remove impurities from different types of surfaces. The image that comes to mind when talking about this subject is that of sanding wood, but it is by no means limited to the field. It is also used in metals and in many masonry and painting works.
It is common to want to skip the sanding process, as it is tedious and confusing. However, it is essential if we want to get a good finish. Not only in terms of softness to the touch, but also in terms of durability. Therefore, choosing the type of grain and sandpaper is fundamental.
Basic process for sanding wood and other materials
The theory is simple. Coarse sandpaper is used first in order to further scrape the surface and remove impurities. In successive passes, the sandpaper grain is reduced to obtain a smoother surface.
On some occasions, when looking for a particularly smooth surface, a last pass can be made with steel wool. It is especially useful in wood.
Types of sandpaper
Not all jobs require the same types of sandpaper. Therefore, not all offer the same characteristics.
In essence, any type of sandpaper consists of a support, usually paper, although sponges are also common, on which grains of some abrasive material adhere. This will be the one that will “scratch” the surface when dragged over it.
According to the size of the sandpaper
- Coarse or coarse grain. It is mainly used to remove paint or other elements from a surface. Values are between 40-80.
- Medium grain. It is the most common, mainly when working with wood, and its function is to smooth. Between 80-180
- Refined. It is mainly used for sanding between coats or finishing applications. 180 to 300.
- Superfine grain. The use of this type of sandpaper is to correct minor imperfections after the last finishing coat or to change the gloss. From 300.
According to the material of which it is composed
- Aluminum oxide. Round grain without sharp edges and good durability. It is used in metal, wood and plastering walls.
- Silicon carbide. Fine grain with sharp edges and little durability. It is mainly used for glass, natural stone such as marble, plastics, etc.
- Zirconium Corundum. Long-lasting and uniform class. For demanding applications, such as stainless steel.
- Support, support:
- Paper. Acceptable strength and flexibility. It is mainly used for woods. It is the cheapest and most common option.
- Water-based sandpaper. The difference with the previous one is that it is impregnated with impermeable products to perform wet sanding. It is used for fine finishes, mainly on metals.
- Sponges Increasingly used for their convenience for small handicrafts in wood and plastering walls. They allow to adapt to the shape of the surface to be sanded.
- Cotton or Polyester. Resistant and flexible. Also with higher prices. It is a common material for hand and belt sanders.
- Vulcanized. It is a much more rigid support with a lot of resistance. For use on metals.
Types of sandpaper according to the shape
There are different sandpaper formats, each one designed for the form or use it will receive. There are more friendly ones for those who are going to sand manually and also for the different types of sanders.
- Sheets. It is the most basic format in which you can buy sandpaper. They can be made of paper or cotton. They are purchased in this format mainly for complex jobs or where you cannot use machines. And also when doing small jobs or DIY.
- Dowels or sponges. Ideal for uneven surfaces and also for trips.
- List. When we are going to use in quantity it is always advisable to buy in this type of sandpaper instead of buying by sheets, as it is cheaper. It is also the shape with which most vibrating sanders are compatible.
- Discs. For eccentric sanders
- Bands. For belt sanders. They are the most used in professional carpentry for sanding large surface parts.