How to choose a paint and varnish product for painting plywood

Why is it necessary to coat paints?

90 percent of plywood is wood, which can quickly deteriorate under high levels of moisture, aggressive influences, combustion and mechanical stress.

To ensure that this material lasts a long time and retains its original appearance, professionals use a special paint and varnish that makes plywood bases stronger and more beautiful.

Painting plywood: step-by-step instructions, types of paints and varnishes

The question of how, and most importantly, with what to paint plywood on the floor, is very relevant these days. Plywood is a material with excellent characteristics that has a fairly wide range of applications.

It is made from fairly thin sheets of veneer, glued with adhesives of different compositions. Such a property of this material as moisture resistance and, accordingly, the brand directly depend on the composition of the glue used.

Photos of plywood of different thicknesses

Surface preparation technology

In order to extend the service life of the material, it will need to be coated with acrylic paint.

The plywood processing process is divided into the following stages:

• grinding process;
• priming work;
• drying;
• puttying followed by drying;
• grinding robots;
• priming work followed by drying;
• coloring

What kind of plywood should I paint?

Today there are about 20 varieties of this material, each used in different directions (this depends on the weight and characteristics of each type) - modeling, construction, design, aircraft construction, repair, design, and so on.

Certain types are used only for production and cannot be found in everyday life.

The most common companies purchased by both professionals and ordinary amateurs are FSF and FC.

FSF is a material that is not afraid of high humidity and is used for outdoor work.

Because it is very strong and resistant to water, it is used to create laminated plywood.

FC is a material that is natural and environmentally friendly, since it contains little impregnating substance, but because of this it is not so durable.

It is often purchased for repair work, for example for:

1. Insulation, leveling.
2. Ceiling insulation, sound insulation.
3. Subfloor for finishing the floor (linoleum, laminate, etc.).
4. Partitions.
5. Roof repair.

Especially for FC, which does not have very good resistance to moisture, a coating with a composition is needed.

Tips for applying varnish

Before coating plywood with varnish, in order for the coating to be effective, the following nuances in the work are taken into account:

1. The composition is applied in the direction of the wood fibers in an even layer.
2. To avoid accidental application of drops of acrylic LM on furniture and floors, they are covered with film.
3. The putty is selected to match the varnish.
4. You can avoid drips if the coating layer is small.
5. The saturation of the shade begins already with the coating of the second layer. The number of layers depends on the desired color of the coating.
6. If plywood is painted with varnishes of different shades, then masking tape is used to create the boundaries of the areas.
7. If the main concern is not the appearance of the coating, but its moisture resistance, then drying oil is used as a covering material. The plywood is not just coated, but impregnated. Therefore, the material is purchased with a reserve. Each layer of drying oil is dried with a hairdryer. This is repeated until it stops being absorbed into the base.
8. To enhance the color of the wood, the sheets are pre-treated with stain of the desired color.
9. Since you have to work with a chemical mixture, you need protection for the eyes, exposed skin, and respiratory tract. Wear a respirator, goggles, and overalls.

What varnishes are suitable for this procedure?

When choosing such a substance, it is often advised to take into account the possibility of the varnish forming a film.

It comes in two types:

1. Polymerization. Painting with a complex chemical agent, which after drying forms a reliable hard layer. This includes varnishes based on polyester, alkyds, oils, polyurethane and formaldehyde.
2. Solvent evaporation. This includes paints and varnishes that contain alcohol and nitrocellulose.

Compositions based on alkyds, pentaphthal resins, and glyphthal (GF 166, PF 283, 231) are in great demand for home use.

They are colorless (rarely with a brown tint), have good adhesion to the surface, are not afraid of water, and can be used for external and internal work.

Drying one layer of this varnish takes approximately 36-72 hours; you need to use a brush again for painting.

Oil-based varnishes, like alkyds, contain natural or artificial resins, as well as oily thinners.

The layer turns out colorless (sometimes with a yellow tint), hard.

These substances are used to cover floors, souvenirs, furniture, and so on.

Compared to alkyd products, such varnishes have one drawback - they are susceptible to precipitation and have a long drying period.

But the modern market already sells oil-based varnishes that contain a certain amount of resins, due to which such compositions dry in 12 hours and become more resistant to weather conditions.

Nitrovarnishes are a good option for protecting plywood products.

Drying time is up to half an hour, and the coating has a completely transparent effect without any tint (NTs 222, NTs 221, and so on).

Epoxy compounds are a mixture of epoxy resin and an organic thinner.

Before the coating procedure, a hardener in the required amount is mixed into such a varnish.

After about 24 hours (drying time), a durable coating with a transparent effect is formed, the only downside of which is that it is susceptible to atmospheric influences. This means that this varnish is excellent for interior decoration.

Polyurethane-based products are also good for protecting wood.

With their help, a transparent coating is obtained that creates protection from various mechanical influences, aggressive chemicals and water.

Drying time is approximately 4-12 hours. Today this is one of the best remedies.

Varnish application technology

Before varnishing plywood, its surface is treated. The wood texture is preserved and there are knots on its top sheet.

1. If a smooth surface is needed, then the plywood is sanded and primed. Sandpaper is used for leveling. Perpendicular to the texture, the plywood is processed with paper with a coarse grain of 80-100. The surface is smoothed with fine grain sandpaper along the fibers. For large areas covered with plywood, it is recommended to use a sander. Don't forget to trim the edges of the sheets.
2. An acrylic or alkyd primer is applied to the entire surface of the plywood structure. A roller is used. The primer layer eliminates minor defects, serves as an additional barrier to moisture, and prevents the appearance of mold. Its main purpose is to strengthen the adhesion of the LM to the base. This guarantees a smooth varnished surface.
3. Before being coated with varnish, the surface is cleared of debris after sanding.

Important: no matter what varnish is used (matte or gloss), knots are visible on the surface. Treatment with putty is not done. Therefore, the preparatory stage comes down to eliminating all defects. The varnish is applied to smooth plywood.

If you cover LM painted plywood, its surface will shine with a glossy coating. The varnish is applied strictly according to the manufacturer's instructions. The composition is first mixed and settled. At this moment, air bubbles come out.

Plywood is covered with a multilayer coating. The thickness of each layer is small. This avoids drips. The drying time for one coating is indicated by the manufacturer on the container. At the time of working with the material, the room is not ventilated, drafts must be avoided, personal protective equipment (respirator, gloves) is required.

The first coating layer is applied along the wood fibers. This way the smallest cracks are filled with the composition. If it is not thick, it applies easily and evenly. A thin layer dries quickly.

A brush is used as a painting tool for hard-to-reach places on floors and walls, it is convenient to work with a roller with a foam roller, and complex shaped structures are painted with a spray.

On the surface of plywood you can create a textured wood pattern to imitate a plank floor. To do this, purchase plywood without defects (at least grade 2), sheets with a pattern and fiber texture, and transparent varnish. On the construction market, you can immediately purchase sanded plywood of the desired grade, cut to size, and therefore the ends will be free of burrs. The process of varnishing a plywood structure made from such sheets will be much easier.

How to impregnate plywood for moisture resistance?

Why is it not easy to buy moisture-resistant FSF brand, laminated or bakelite plywood? As a rule, such material is more expensive, so it is sold only in bulk and to order. The question of how to impregnate plywood for moisture resistance can be answered using the following processing methods:

• treating plywood with drying oils - impregnation with water-repellent oily compounds (not paints!), forming a greasy film deep in the wood structure, followed by application of varnishes;
• to impregnate plywood, use moisture-proofing primers - the antiseptic contained in the composition prevents the growth of pathogenic mold;
• treatment of plywood with water-repellent agents – application of hydrophobic compounds prevents moisture from entering between the layers of multi-layer plywood material;
• strengthening plywood with reinforcing water-repellent fiberglass - it is necessary to subsequently fix the fibrous glass mass on a sheet of plywood with transparent varnishes.

To treat plywood surfaces, you can use ready-made varnish compositions 6T or 6C, varnishes for flooring, varnishes 4T and 4C for coating (you can use antiseptics like Pinotex, the main thing is that they are suitable for drying oil). It is not recommended to coat plywood surfaces with polymer epoxy hardening and polyester resins instead of drying oil, since they do not match the composition.

Remember that it will not be possible to impregnate plywood to achieve moisture resistance by simply painting it. Layers of paint are susceptible to cracking over time, so limiting contact with moisture cannot be achieved in this way!

Processing methods

Processing plywood and protecting it from moisture can be done in several ways. Here are some of them (the most common in everyday life):

• puttying with PVA glue;
• coating with drying oil;
• treatment with nitro paints;
• gluing fiberglass.

Next, we’ll take a closer look at the best way to process plywood and how to do it correctly.

PVA

Protecting plywood from moisture and rot with PVA putty has many advantages. It reliably protects the material from many negative factors. Here are step-by-step instructions on how to complete the protection process:

1. Before treating the material to increase moisture resistance, it is placed parallel to the floor and a layer of PVA glue is applied.
2. Allow time for the initial layer to be well absorbed, after which it is covered with another layer of PVA.
3. Continue the process until glue stains begin to appear on the underside of the sheet.
4. The plate is turned over and the impregnation process is repeated.

After the work is completed, the slab is laid on a flat surface and allowed to dry under natural conditions. The disadvantages of this process include rather long processing times. Plywood will have to be protected from moisture for 3-4 days.

Drying oil

Drying oil is the simplest way to impregnate a plywood board from water. Processing is carried out in the following way:

1. The solution (oil for plywood) should first be heated to a temperature level of 60C, due to this its penetrating ability increases.
2. Then we impregnate the horizontally located sheet with drying oil using a brush.
3. After completing the impregnation process on one side, we proceed to the other.
4. Be sure to thoroughly coat the ends of the plywood.
5. When the first layer is applied, we begin to force-dry it using an iron or hair dryer.
6. After drying is completed, we begin the repeated process of applying drying oil and forced drying.

The number of layers may vary. Stop treating with drying oil only when the solution stops being absorbed by the material (the water-repellent effect is fully achieved).

Fiberglass

You can also protect plywood with fiberglass, but to do this you need to use waterproof varnishes that do not contain epoxy or polyester resins. The protection technology consists of the following steps:

1. The sanded plate is painted with varnish.
2. After allowing the applied layer of varnish to dry for about two hours, fiberglass is glued onto the surface of the plywood.
3. Re-apply a layer of varnish to the ends of the slab and leave until completely dry.
4. The treatment is completed by applying another layer of varnish and drying the impregnated plywood under natural conditions.

Nitropaint

Another way to treat plywood from moisture is with nitro paints. This is especially true when the material will be in direct contact with water, for example, when repairing a boat or arranging a damp room.

Here are instructions for doing the work yourself:

1. Initially, it is necessary to sand the surface and cover it with drying oil.
2. Allow the drying oil layer to dry completely and apply liquid paint as a primer.
3. Apply a layer of nitro paint to the sheets protected with primer.
4. We cover the surface of the plywood with a cloth, which at the same time must be impregnated with nitro solvents.
5. After drying is completed, it is treated a second time with diluted nitro paint. The resulting moisture-resistant material is even suitable for making a boat.

Preparation

Before painting plywood, it is necessary to prepare its surface well. If you have just purchased sheets of plywood, you need to give them some time to dry, because it is unknown in what conditions the plywood was stored. In order for the sheets to dry well, it is enough for them to stay in a room with a dry, warm climate.

So, the plywood sheets have dried. Now they need to be sanded well and the surface cleaned of chips and dust. For best results, it is recommended to carry out sanding in two stages. First, treat the surface with coarse abrasive sandpaper (grain size No. 80). Then thoroughly sand with medium-grain sandpaper (No. 100-120).

How to paint plywood

High-quality varnish coating of plywood requires compliance with safety requirements and adherence to GOST standards R 52165 and 9825-73.

Multilayer coating requires pre-sanding with a primer. Varnishing at home is carried out in one of the following ways:

• mechanically (high-quality spraying with a spray gun, applied economically, dries quickly);
• varnishing by hand (most often used for decorative purposes, where the use of mechanical means is impractical or impossible) using a brush or roller.

Before painting, the plywood sheet is sanded, and if there are no defects, a primer is applied. When there are uneven areas, it is recommended to fill them and putty the surface.

Attention! Varnishing is done after the primer has dried, which guarantees better adhesion and a smooth, almost perfect surface.

It is better to apply the coating in 2-3 layers, the first time the varnish is applied across the fibers in order to achieve complete filling of small crevices characteristic of wood texture. The thinner the varnish, the more evenly it is distributed and the faster it dries. If the composition is too thick, dilute it according to the instructions with an appropriate solvent. Allow each coat to dry completely, especially before final application.