Features of problem
One of the important factors in painting a beautiful and smooth paint film apart from having a good surface is the painting equipment whether it is the brush, roller, spray, depending on the nature of use and proficiency in using the equipment. If the equipment is used incorrectly, it may cause scratches on the equipment, such as paint rollers where the roller joints are formed on the wall and not smooth especially when looking obliquely reflected with light.
Causes
Roller mark problem can occur from several reasons as follows:
1. Caused by the wrong colour rolling from the work of a painter such as the paint is rolling while the surface is in high temperature. The paint will dry too quickly. When applying the second coat while the first coat is drying or rolling over the same tracks while the surface of the paint is about to dry, it can cause roller marks to usually occur with exterior painting on windy days and very hot weather. It is often found with high-altitude paint work such as tall buildings, signage, etc.
2. Caused by mixing too little water. As a result, the colour is very thick. When painting, it can form a roller mark. Excessive rolling of the paint roller, too thick rolling paint, or even the use of rollers that are not suitable for the job, low quality paint, poor colour flow performance can also cause roller marks problems.
3. In case of oil paint, when it is used or the lid is left open while applying, it will cause thinner in the paint to evaporate. The colour is thicker and more viscous. When painted, the paint will stick together in a long way and not spread evenly
How to solve
Use fine-grained sandpaper to polish the paint film that has problems with roller marks to be smooth. Then, clean the surface to be free of dust. After that, repaint over the paint by mixing the required amount of water into the paint.
In case of acrylic paint, the first coat of paint should be allowed to dry for 2-4 hours before the second coat of paint (depending on the weather).
Choose a quality roller or choose a roller coat type to suit the paint and condition of the job, for example, using a long-haired roller will cause roller marks more easily than using a short-haired roller. However, short hair rollers release less paint than long hair rollers, requiring multiple coats of paint.
How to prevent
1. We should choose quality paint equipment and select the hair type of the roller to suit the type of paint and texture from cement surfaces, plaster walls, skim-coat walls, wood, metal to consider whether it is a rough or smooth surface. Usually, a smooth surface is suitable for short-haired rollers and rough surfaces are better suited to furry rollers.
2. The rolling of paint should be avoided while the surface is exposed to high temperatures. Or on windy days, very hot weather, working in the altitude, if the paint is needed, it should be mixed with a little more water and should avoid rolling over the same tracks while the surface of the paint was about to dry.
3. Use a brush to paint details around the edges, corners, frames first and then use the roller on a large area. Roll the paint in a W-shape without lifting the roller in order to avoid the problem of colour seams. It should paint each round evenly. The same wall should be finished in one wall to allow the paint to dry at the same time so that it will be easier to calculate the next paint cycle time.
4. To reduce brush or roller marks, the solvent such as water or thinner should be used by adding a little amount of about 5 – 10% and stir well each time before applying. It will help the paint slip and flows well. The paint film therefore comes out smoother and more beautiful.
5. In the case that the wall has a wide and high area, the Airless Sprayer should be chosen instead of rolling paint in order to get smooth, beautiful paint film and get fast performance.
