What is sanding, and why is it important?
Sanding is the process of smoothing, polishing, or cleaning something by rubbing it with an abrasive object, usually a sandpaper. Sanding is one of the fundamental processes for lacquer or varnish to achieve professional results. It is a vital element of the process to achieve a good result since it aims to remove marks and smooth the surface in order to apply the paint or varnish perfectly.
The objective of sanding is to eliminate damage to the wood allowing the surface to be leveled and smooth, providing an ideal condition for the application of chemicals such as sealers and lacquers.
How to choose a type of sandpaper?
Not every job calls for the same kinds of sandpaper; This means that not all sandpapers offer the same characteristics.
Any sandpaper consists of support, usually paper, though sponges are also common, on which grains of some abrasive material adhere. This is the material that will “scrape” the surface when it is dragged over the wood. There are a lot of abrasive materials available, but the most commonly used for sanding wood is Aluminum Dioxide, so we won’t bother with the others for now. What’s important is the size of the grain, since it is the element that affects the finish the most.
Types and uses of sandpaper depending on the grain size
Coarse grain. It is mainly used to remove paints or other elements from a surface. Values are between 40-80.
Medium grain. It is the most common, especially when working with wood, and its function is to smooth. Between 80-180
Fine-grain. It is mainly used for sanding between different coats or finishing applications. Between 180 to 300.
Superfine grain. This type of sanding is used to correct small imperfections after the last finishing coat or to alter the shine. From 300 onwards.
How do you use sandpaper?
The sanding of a surface is done by longitudinal manual movements on it, in such a way that the granulated part of the sandpaper rubs the area to be sanded. In the case of wood sanding, the movement should follow the direction of the wood grain. For higher and more uniform force, a flat piece of wooden block can be used to help apply the necessary pressure. In addition, there are electric sanders, in which the sandpaper is attached to a contact disc that, when it rotates, performs the work on the object with greater efficiency and speed.
Tips for using sandpaper
Use a wooden block
The wooden block is the perfect tool for this task. The cue guarantees that the sanding process is uniform, an effect that we do not achieve by pressing the paper with our fingers.
Cut only the sandpaper you need
To sand wood, you only need enough paper to cover the cue. If there are any leftovers, you may find this task more uncomfortable. On the other hand, don’t forget to use a sharp edge to cut the sandpaper (pulling the end you want to remove), never a pair of scissors or blades. This is because, in this way, the material will tear following its internal texture.
Sand in the direction of the grain
By sanding in the direction of the wood grain itself, you will achieve a more elegant and smoother finish. If you have sandpaper that includes an arrow with the direction in which it should be used, it will also be of great help. There are many different types of sandpaper so it is important o make sure you choose the right type depending on the surface material that you are sanding.
Can I use a sander?
Although hand sanding can be much more precise and helps us get more professional results, it takes a lot more work than machine sanding. Therefore, if you are not a person who loves manual work, we recommend that you always sand with a sanding machine or an electric drill with a sanding attachment, as the time saved will be very considerable.
Types of Sanders
An electric sander is a tool that will allow us to carry out all kinds of sanding work comfortably and efficiently. When you buy a sander, you must take into account the use you are going to make of it and the results you are looking for. Choosing the right sander for each job is essential, as it must be adapted to the material we are going to work with and the use we want to make of it. These are the most common types of sanding machines.
Orbital sander: It has a rectangular sanding plate, which oscillates parallel to the work surface. It is mainly used for fine sanding, generally in areas of easy access and medium-sized surfaces.
Belt sander: Due to its delicate and concave sanding, it is the ideal sander for roughing, for sanding in curves, and also for fine sanding of different materials. They are therefore suitable for renovating wooden furniture, even when the grain is very pronounced, because of their high roughness and high-quality finish.
Delta sander: This type of sander has a delta-shaped sanding, hence its name. The purpose of this sander is to be able to reach corners and edges that may be inaccessible with any other type of sander. Its lightweight makes it a convenient machine.
Recommendations before using a sander
When we start working with a sanding machine, we must ensure that the abrasive is well stretched and well fixed on the sander, we must verify that the surface to be sanded is free of nails or metallic elements that could damage the tool or the sanding. We must fix the material to be sanded correctly on a stable working base.
Once we are finishing the work, and before the last sanding, it is advisable to wet the surface of the wood slightly. This way, the fibers that remain to be sanded are lifted, and the finish will be perfect.
If sanding is ineffective, it may be because
- The abrasive is used.
- The abrasive is dirty.
- Its grain is not suitable for the surface to be sanded.
Wiping Varnish or simply oil-based varnish, which is thinned with white spirits, is recommended when you are finishing for the first time and one you can easily make on your own. We hope that all these tips will help you when carrying out your projects with wood and always remember that if you are going to buy a sander, you must use it correctly, taking care of the wood to obtain the best result.