Primer paint is one of the most important steps that must be applied before starting the painting process in general. This applies to both wall paint and woodworking. As the primer paint ensures better adhesion to the final coat of paint that is applied, it also increases the durability of the parts being painted, and works to protect them further. In this article, an explanation of how to choose primer paint based on where it is used and how to solve the following problems.
Do I always need to paint primer?
If you intend to paint a previously painted surface, there is no need to paint the primer provided that the old paint is in good condition so that there is no peeling or cutting in the paint. Also, the inner walls usually do not require primer coating except in the event of stains, repairs, molds or odor attached to the wall. As for the outer walls or the pieces of external wood, most of them need to always paint the primer.
Types of primers paints
There are two main types of primer paints, and each of them is divided into special types that have certain additions for processing something, such as mold or others. The main types are:
1- Oil primer
Oily primers are suitable for final oil-based or latex paints, making them versatile, and applicable to a wide range of surfaces. It is an excellent choice for wooden surfaces (painted or uncoated), and for iron and metal surfaces in general, as well as for previously painted walls, whether interior or even exterior.
Also, oil primers are a stain preventive from appearing in new coatings, such as ink and water stains. It is also ideal for previously unpainted wood because it can seal the pores in the wood.
The disadvantage of a primer is that it is often slow to dry, as it releases large amounts of volatile organic compounds (VOCs), which can be harmful to people with prolonged exposure. It also requires you to use harsh thinners and solvents to clean the brush.
2- Latex primer
They are water-based primers, which are ideal and suitable for gypsum boards, they are more flexible and faster in drought than oily, and they are also less fragile than oil primers, which makes them less prone to peeling and cracking. Also suitable for dry walls and any repaired areas.
It can also mask previous small spots of smoke, lipstick and crayon, but it is not effective in covering stains as oil-based scripts. They are safer because there are no VOCs and they are differ quick cleaning.
How to choose a primer paint?
1- Unwashed interior woodwork
It is necessary to paint unpainted wood with primer paint, as the surface of the wood is thirsty, and it is full of defects, so this stage is necessary to maintain the final layer of paint. Slow-drying oil-based primers provide better and easier cohesion in the sanding process than water-based primers.
2- The new gypsum board walls
The new gypsum board walls are distinguished by the presence of an outer layer that has the ability to absorb paint differently from the rest of the dry gypsum board panels, this difference may lead to a difference in the degree of glossiness of the paint, and to solve this problem, it must be used with primer (in one package) special for gypsum boards, preferably water-based.
The first step before applying primer to sealer is to sand the surface of the boards, to remove any smooth heights and get a smooth surface. Then a special traditional primer can be used for gypsum board surfaces. After applying the primer layer, it is advised to apply the final paint within 48 hours of finishing the primer coating.
3- Inner spots and musty smells
If you use a regular primer or paint, the inner stains and odors in the inner walls will appear on the paint regardless of the number of coatings you have applied. So, the solution with these stains is to use a primer against stains, which is available in one of the following two types:
Anti-stain oily primer: This type has the ability to get rid of unpleasant odors and requires a thinner layer of paint to clean it. It has a high ability to prevent water-based odors and stains, such as rust, nicotine, smoke, woody tannins (tannins), and of course water.
Anti-stain water primer (acrylic or latex): This type has the advantage of being easy to clean and smells less oily. It also has the ability to prevent solvent-based stains such as chalk, grease and ink.
4- Places with high humidity
In the case of painting surfaces in places with high humidity, such as kitchens, bathrooms, and washing rooms, it can cause mold and moisture to appear in the walls, thus causing scaling of the paint, and bubbles appearing on the walls. First of all, use a “steam insulation primer” to reduce the passage of moisture. If the mold is fungal, an anti-stain and anti-mold primer must be used. But before doing so, mold must be killed by wiping the walls with a mixture of bleach (one part) with water (3 parts).