27 / Sep / 2022
The importance of sanding for good painting results
In this blog we explain why sanding is important in the painting process and give advice on how to prepare your wood for the job.
Importance of sanding
Sanding is an especially important aspect for the preparation and treatment of the wood. Like cleansing, sanding ensures that the paint attaches to the wood better. If the wood is not sanded or cleansed, the paintwork will be more vulnerable. However, if the preparation is not done well, the final layer of paint will contain irregularities. You could be using the best coating in the world; it will never obtain an even result. Sanding a surface before painting it helps to create a smooth, even surface for the paint to adhere to. This can help to ensure a more consistent and professional-looking finish. Additionally, sanding can remove any dirt, grime, or other debris that may be present on the surface, which can help to prevent imperfections in the final paint job. Sanding can also help to remove any old paint or varnish that may be present, which can help to ensure better adhesion of the new paint.
Wood is made up of fibers. It is important that these fibers will not protrude through the paint because it would create a leak in that layer of paint. With sanding, you ensure that the pores in the wood open, the surface of the wood swells, and the fibers in the wood get removed. Because of this, the paint gets the chance to soak into the wood to create a nice finish. This preparation is important for many kinds of wood, such as oak.
Impact of the scratch
You can sand in two separate ways: by hand or by machine. Using a sander makes for a consistent result on larger surfaces. It all depends on the impact of the scratch. The sanding paper regulates the depth of the sanding, which is why it is important to know the product with which you are working.
The effects can differ with every sanding paper. So, if you are switching brands or variations, make sure you still get the desired results. However, if you are using a sander, determine if the sole of the sander also creates desirable results. The firmer the sole, the deeper the scratching. Establish your goals first and adjust your sole and paper to that goal. In the joinery industry it is most common to use orbital sanders with mesh finishing pads.
Finishing pads are special types of pads . They are typically made of foam or other soft materials and are used with fine-grit sandpaper to achieve a smooth, polished finish on wood, and other surfaces. They come in a variety of shapes and sizes, and can be used with different types of power sanders such as orbital sanders, random orbital sanders, and dual-action sanders.
On the contrary, automatic belt sanders are a type of power tool that uses a continuous loop of sandpaper to sand large surfaces quickly and efficiently. They are typically used for woodworking and metalworking applications, and can be used to sand down rough surfaces, remove paint, and create a smooth, even finish. They are called "automatic" because they have a conveyor belt system that automatically moves the material through the sander, this allows the operator to work on multiple pieces at the same time.
Examples of producers are:
Boere: http://www.boere.nl
Homag: https://www.homag.com/en/products/surface-technology/sanding-machines
The grit of the belt on the first drum should be as fine as possible. We advise between 120 and 140
The finishing belt should be 180 grit up to 200
Sandability of paint systems
Not every paint system is easy to sand. Sustainable paint systems such as lacquers contain more binders and are more difficult to sand. We recommend you use sanding paper that fill up at a slower rate and use a decent dust extractor.
However, primers are easy to sand. They fill the surface of the wood and provide a substrate for the paint. The adhesion between two layers of paint is called a chemical adhesion. In a certain timeframe after the application of the first layer of paint, this adhesion is still active and does not require any sanding before applying the second layer.
Polishing
Polishing is the process where a surface becomes smooth and shiny, causing a strong mirroring effect. Polishing is no ordinary job, it is artisanship. If the object has been sprayed very well, it does would require less polishing afterwards. Think of those gorgeous shiny pianos for example. Sanding can take lots of time, but if you do it well it will be worth it!