What is primer paint?

Primer paint is a base coat that is applied to a surface before painting to improve paint adhesion, seal porous surfaces so that they are uniform and the paint is absorbed, and ensure a durable finish. It acts as a bridge between the surface and the paint, helping the paint to adhere properly and preventing problems such as early flaking due to poor adhesion to the surface.

In addition to improving adhesion, it also helps to hide stains and reduce the number of coats of paint needed to achieve complete coverage. It is especially useful on new surfaces, restorations, or surfaces with deteriorated paint (provided that the area is properly prepared—cleaned and sanded where necessary).

Before you start priming, especially if you have never done it before, you may have many questions about the types of primers available, the number of coats, how long to wait before painting, how to apply it correctly, or which color is right for each case. Below, we will explain all of these questions step by step, leaving a table at the end with specific information for a wide variety of materials.

Main types

We will start by distinguishing between some fairly common types of primers.

What are makeup primers?

In makeup, primers are products applied before foundation to prepare the skin, just as any material is prepared to achieve the best effect when painting. Its purpose is to smooth the skin's texture, minimize pores, control shine, and make makeup last longer. There are different types of primers depending on the specific needs of the skin. Depending on each person's skin type, they can be classified mainly into mattifying, illuminating, moisturizing, and texture-unifying primers. Depending on their texture, they can be found in cream, gel, oil, or spray form. Some primers even try to combine everything in the same product.

Makeup primer is used mainly in elaborate makeup applications by experts, not in simple everyday makeup, although it is recommended for longer-lasting results.

What is deep penetrating primer​ ?

Also known as a paint sealer primer​, it is a type of liquid primer with high penetrating power. It is used on very porous, degraded, or powdery surfaces to consolidate the substrate and prevent excessive paint consumption. It is especially useful on plaster walls, cement, or surfaces with dust residue.

This type of base coat penetrates deeply, strengthening the surface and improving paint adhesion. It is ideal for preparing surfaces that have cohesion problems or have been recently repaired.

What is acrylic gesso?

Gesso is a white acrylic primer used mainly on artistic surfaces such as canvas or wood. This mixture is a combination of a binder to which plaster, chalk, pigment, or a combination of two or more of these components are added. It is usually applied with a spatula and provides a porous, rough base that allows paint (oil or acrylic paint) to adhere better. It can also be tinted and thinned with water for use with a roller. In addition, it prevents the paint from being absorbed excessively by the substrate, ensuring more vibrant and durable colors.

Gesso can be applied in several layers, waiting about two and a half hours between layers and sanding between each layer to obtain a smoother surface. It is an essential tool for artists who want to prepare their canvases (or other types of surfaces) before painting to achieve optimal results in their artwork.

Tips for applying primers

Next, we will answer the most frequently asked questions before starting to prime, so that anyone can do it with confidence and assurance.

When to use primer paint​?

It is applied to new, porous, repaired, or deteriorated painted surfaces before applying the final coat of paint. It is also used when the color of the surface is going to be drastically changed to ensure even coverage and prevent the previous color from affecting the new finish.

In addition, the base coat is essential on difficult surfaces such as metal, plastic or glass, where the paint may not adhere properly without adequate preparation. In these cases, it ensures a durable and resistant finish.

Why is primer applied before painting?

Applying primer before painting is good practice when seeking a professional finish. Its functions are:

• Improve the adhesion of the paint to the surface.

• Seal porous surfaces, preventing the paint from being absorbed unevenly.

• Provide a uniform finish, reducing the number of coats required.

• Extend the durability of the finish by protecting the underlying surface.

How long does it take for primer paint to dry?

The drying time of the primer varies depending on the type of product and the environmental conditions. Generally, it is recommended to wait between 2 and 6 hours before applying the paint. However, some primers need up to 24 hours to dry completely. It is essential to consult the manufacturer's specifications for optimal results.

It is important to bear in mind that factors such as temperature, humidity, and ventilation of the space can affect drying time. Make sure the surface is completely dry before applying the paint to avoid adhesion or finish problems.

How to apply primer paint?

The base coat can be applied with a brush, roller, or airbrush, depending on the type of surface and product. There are also spray primers, which are widely used in model-making. Before starting with this coat, the surface must be clean, dry, and free of dust or grease.

It is recommended to apply an even coat and allow it to dry completely before painting with the final color. In some cases, depending on the surface to be painted, it may be necessary to sand the surface lightly after priming to achieve a smoother finish.

In any case, the correct application of each primer, and depending on the method chosen to use it, depends on the characteristics of the product, so the best way to do this is to follow the manufacturer's instructions and take into account the most suitable tool for your product and the surface to be primed.

What color is primer paint?

Not only do you need to know how to prime correctly to get a good result with the paint, but choosing the right color will also have an influence.

• White. this is the most common base coat color, especially for interiors and light finishes. It provides a neutral and bright base. It enhances the final color, especially when applying white, beige, pastel shades, or bright colors.

• Gray. This color has become fashionable in interior painting and is recommended for darker colors, as it reduces the number of coats needed to cover the surface, achieving a good result and preventing loss of depth. It can be used with gray, dark green, brown, and other paints.

• Black. This is the most useful for painting with metallic colors, dark finishes, or dramatic effects. Its use in model making is highly valued because it allows natural shading effects to be created with techniques such as “zenithal highlighting.”

• Transparent/colorless. This is used when you do not want to alter the base color (such as natural wood, stone, or marble) but need to seal the surface while maintaining its natural appearance.

These are the most common primer colors, although in specific contexts other less common shades may be more appropriate, such as rust red or brown in industry and metallurgy, where it acts as an antioxidant on metal surfaces, especially iron and steel. It can also be an option for warm colors such as reds, oranges, and earth tones.

Green is also an option, although it is used in limited contexts. Its most prominent use is related to painting machinery or structures that are to be painted military green or camouflage, as is the case with military vehicles in model making.

Sometimes, in professional painting, primers are tinted with compatible dyes to match the shade of the final paint, to reduce the number of subsequent coats of paint, especially in very bright or intense colors, although this is not the most common practice. This technique is mainly used when changing from a very dark color to a light color or vice versa, creating a “medium color” according to the color scheme of the project.

How long does the primer last?

In the case of priming applied to a surface, it can remain in good condition for weeks if not painted immediately, although it is best to paint within 24 to 48 hours, especially to avoid dust accumulation on this base coat, which would reduce the quality of the paint.

Unopened and properly stored, the product can last from 1 to 3 years. However, to know for sure, always follow the information and advice provided by the manufacturer, as not all products are formulated in the same way.

Keeping the primer in a cool, dry place, away from direct sunlight, always helps to preserve its quality and effectiveness.

How much is primer paint?

The price of a can of primer can vary greatly depending on its size, format, brand, finish, and even color. A liter can cost from just over a dollar for larger containers to €50 for special or high-performance primers. It is important to consider the quality and suitability of the product for the type of surface and paint to be used. In fact, investing in a quality primers can save you time and money in the long run by reducing the amount of paint needed and increasing the durability of the finish.

That's why we recommend Green Stuff World's acrylic priming or spray primer, especially if you're looking for a product for miniatures and diagrams at an affordable price but with high quality. We have primers in various colors, sizes, and finishes so that no project is left without the right product for the job. They can be purchased at the official GSW store, at one of our retailers around the world, or on our official profile on the Etsy or eBay marketplaces.

How to apply primer paint according to the material

Below is a table with many of the materials that can be primed, along with the most common type of primers and color, as well as the drying time and application method.

The data in this table is approximate and general. Depending on the finish required for each project, as well as the product used, these parameters may vary. We recommend consulting an expert to purchase the appropriate primers and follow the manufacturer's instructions.

Primer in modeling

As in other areas of the art of painting, this base coat is also an essential technique in model making. In this case, the base coat is applied to a figure or model before painting. Its function, as mentioned above, is to improve the adhesion of paints, reveal details, and prevent the paint from flaking off with use or over time.

Specifically, in model making, plastic, resin, white metal, or even cardboard or MDF (medium-density fiberboard) pieces are primed, although resin-printed pieces are most common. Without primer, the chances of the paints not adhering well, slipping, forming lumps, or requiring many coats to provide good coverage increase.

Types of primers depending on the product

The two most common types of primers are spray and can. They are usually acrylic, although for specific techniques, oil paints, or on specific materials such as metal, alkyd (oil-based) primers are also used.

Spray

Using a spray has several advantages, such as speed, practicality, and its ability to cover large surfaces well. It is also relatively easy to use, making it ideal for beginners in miniature painting. It is ideal for large projects, scenery, or as an alternative to an airbrush when one is not available.

However, one disadvantage is that control is limited. With a spray, it is difficult to prime details without staining the rest of the figure. For this purpose, it is more useful to use an airbrush or paint with a miniature paint brushes. Similarly, it is very dependent on the weather, as humidity or cold can affect both the paint inside the can and the finish once applied to the miniature.

Bottle or can (paint for brush or airbrush)

In this case, you have much more control over the area to be primed, although you must use it carefully to avoid leaving brush marks or textures if the product is not diluted or spread correctly. It is perfect for small areas or figures and is more durable and provides a better finish in cold weather.

In addition, applying the base coat with an airbrush allows for impeccable precision, provided you have the proper knowledge of how to use this tool. It allows you to apply thin, even coats, as well as adjust the intensity and direction. The only disadvantage of this method is the need for extra equipment (airbrush, compressor, and relevant cleaning supplies).

Choosing the primer color

In the case of miniatures, there are also several colors that can be used as a base coat, depending on the needs of each project.

• Black. This is the most common because it hides mistakes and creates natural shading in hard-to-reach areas, as well as giving a good finish to most colors, especially dark ones. In this case, more work will need to be done on the highlights and light colors.

• White. This highlights light and bright colors (reds, yellows, oranges, etc.). It is useful when you are looking for a clean, saturated finish. Another option is to prime the entire miniature in black and then use white with a slight tilt in the area where you have decided that the sunlight would hit the figure (Zenithal Highlighting). This helps guide the shading and highlights during painting.

• Gray. More balanced for mixed projects where you don't want an effect that is too dark or too light.

• Other colors. There are primers in other colors that are used when a large part of the surface is going to be a certain color: brown primer if the mini is predominantly red (large red armor), dark green primer if green will predominate (orcs and goblins), etc.

• Custom color: there are primers that can be dyed, although this process can be delicate and spoil the result if the correct products are not used in the right amount.

Primer for painting with chrome effect paints

There are primers with different effects, which will have an impact on the final result after painting. It is especially important to choose the right type of primer finish if you are going to paint with specific effects paints, such as chrome spray paints.

Types of surfaces to prime in modeling

Role-playing game miniatures are usually printed in resin, to which a base (wood or plastic) and accessories made of other materials must be added. In addition, for those who still have old figures, they may be made of white metal. This is why it is important to distinguish between the different materials you may encounter in the world of model making and how to treat them.

• Resin: If you print at home with resin for 3d printers, it is important to wash the miniature thoroughly with isopropyl alcohol (IPA) before printing. Green Stuff World acrylic or spray primers are a good option for these miniatures.

• White metal (antique miniatures): Resin products are usually compatible with this type of miniature, although there are also specific products for metal. Without primer, the paints will not adhere to this type of surface.

• Plastic (polystyrene, ABS): Acrylic or polyurethane primers are recommended.

• MDF/cardboard: Mainly used for bases. This material is absorbent, so it needs a water-based sealing primer or pore filler before painting, although it is fully compatible with acrylic primers, so you can use the same product for both the miniatures and the bases.

Essential tips for beginners

Although applying one or more coats is not particularly difficult, if you have never done it before or are just starting to experiment with this process, you should be clear about a few basics:

1. Clean your miniatures before priming: grease, mold residue, or dust can prevent the primer from adhering properly.

2. Apply thin coats: especially on miniatures with lots of detail. It is better to apply two light coats than one very thick one. This will ensure that everything is completely covered, including the smallest or most hidden details and gaps.

3. Shake the spray can well or mix the contents of the bottle: poor mixing will cause drips, bubbles, or a poor finish.

4. Keep the right distance when using spray: about 20-30 cm. Don't get too close or you'll get drips on the surface.

5. Allow to dry completely before painting: at least 1 hour, although 24 hours is ideal for optimal curing.

6. Use quality primers: specialist brands such as Green Stuff World are the best option for professional results.

7. Don't be afraid to experiment: the primer can also be sanded with fine-grain sandpaper, modified, and reapplied if something goes wrong.

Priming is an essential step in model making and can make the difference between amateur and professional work. Choosing the right type of product, application method, base color, and compatibility with your paints will make painting much easier and more satisfying. Whether you are just starting out or have been painting miniatures for a while, mastering priming is an investment in quality, time, and results.