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Why does a wooden panel warp when painted? How to store furniture board? What to do after purchase

Here the other day, at the request of a good friend, I created such a shelf in the image and likeness of existing ones. Size approximately 270 by 200 mm, material - furniture board and a piece of pine board for the leg. Some people like these - it’s a little thing to put in or something else.

And I want to tell you about how to process such a craft not only to give it a marketable appearance, but also to improve resistance to the external environment - primarily water and moisture, because The shelf is designed for a “kitchen” netbook. Moreover, you can process not only a shelf - the same cutting board, a beautiful wooden spoon, or even a simple cut of a trunk, which is used as a stand for hot dishes or for cups.

While making knife handles from very beautiful and expensive materials such as Arizona ironwood and amboyna, I spotted several simple and effective recipes for processing wood on thematic forums in order to emphasize its beauty and protect it from moisture. I will share them.

Firstly, we will not talk about varnishes. I am not against this, but no varnish, in my (and not only) opinion, will give such beauty to the wood pattern and ease of restoration of mechanical damage that the use of various oils provides. Secondly, it is necessary to take into account the fact that the photographs were taken from an ordinary pine furniture panel, the beauty of which initially tends to zero. For those interested, I have entries in my journal about knives whose handles are made of more noble materials and processed in the same way.
Let's call the first stage preparatory - the surface of the product is prepared for coating. Those. made as smooth as possible. Everything is clear here - sandpaper and a lot of patience. But, as in the simplest matter, there are some tricks. Like, for example, the number of sandpaper. It determines the size of the abrasive grain and, if memory serves, is measured in the number of sieve cells per square centimeter through which the abrasive is sifted. Those. paper with the number 40 is very “angry”, and with the number 600 it is “soft”, reaching a soft velvet of 2500 units, which is used for polishing.

The first rule is that the denser the wood, the more carefully the processing should be and the higher the number of the final paper should be. The paper numbers should differ approximately 2 times from each other. Those. something like this: 40 -> 80 -> 150 -> 300 -> 600 -> 1200 -> 2500. Which one to start with and which one to stop at is decided experimentally; for crafts such as furniture, it’s enough to stop at about the 300th number.

The second rule is that each subsequent sandpaper must completely remove the risks from the previous one. And nothing else. From here we can draw a conclusion about the quality of the paper itself. Just a few grains of a larger abrasive dropped onto a sheet of paper can leave noticeable marks on the surface that cannot be erased with the same sheet. But this is rather for fanatics of perfect finishing.

Rule number three - when processing surfaces, try not to keep the sandpaper “on your finger.” If it is large, then you can easily wipe out an unplanned recess on a small part or roll the necessary edge. Therefore, in such cases, it is easier to wrap it around an object of suitable size (even the same pencil) a couple of times and use it like a file.

Another important point in technology is raising the pile. The surface of the wood, no matter how smooth it is sanded, will fluff a little when wet. Thin fibers rise like bristles and, when dry, remain standing as dry stubble. The same thing will happen when covering the surface with varnish, stain or something else. Therefore, you just need to moisten the surface with water (with a rag or from a spray bottle), let it dry and go through it again with fine sandpaper (approximately 800-1000 number), removing hairs. If necessary, the operation can be repeated until the hairs stop rising after wetting. Instead of water, you can use more volatile things - alcohol or vodka.

Now the surface is ready for finishing. More about this next time.

For example, one of my knives, the handle of which was processed almost according to the technology described.


Scandinavian Mjollnir. The handle is made of elk horn, oak root, amboyna, fiber and brass as decoration.

These semi-finished products are used to produce most wood products. This is a natural, environmentally friendly and durable semi-finished product. The furniture panel is made of solid blocks of wood glued together with special glue.

Furniture panels are used in the manufacture of the following products:

  1. Cabinet and upholstered furniture.
  2. Interior elements such as wall paneling, shelves, frames.
  3. Components for the staircase - railings, steps, decor.
  4. Joinery for finishing windows and doors.
  5. Decoration of a personal plot - benches, trellises, awnings.

Furniture panels are made from oak, ash, pine, beech and other tree species.

When working with furniture panels, many encounter a problem when the material deforms and leads to it.

Curvature of furniture board

Wood is a natural material that is intensively affected by the natural environment. Wood actively reacts to environmental humidity; it is able to absorb moisture or release it. The main release of moisture is observed through the ends of the shield. A situation is created that in the middle of the product the humidity is 10%, and at the ends it is half as much. This is what leads to deformation of the sheet.

The main reasons for the deformation of furniture panels are divided into two types: technological error and storage error.

A technological error includes failure to follow the rule: In the process of producing furniture panels, blanks (lamellas) are stacked on top of each other in such a way that adjacent lamellas have the opposite direction of the fibers.

Storage error can be divided into three components:

  1. Wood products were stored without packaging or the packaging was damaged.
  2. The furniture boards were unpacked immediately after delivery; they could not rest in room conditions for several days. This must be followed especially carefully in the cold months, when the difference between room and outside temperatures is significant.
  3. Storing furniture panels in a room with high humidity. These are the rooms where plastering, painting, and screeding work takes place.

To ensure good preservation, furniture panels should be kept in a dry, well-ventilated area. They must be laid out in a horizontal room on three or more transverse spacers. It is recommended that after opening the package, treat the ends with a protective material - varnish, wax, oil.

Rules for working with furniture panels

It is advisable to purchase furniture sheets in advance:

  1. Before installation, the material must remain at room temperature for a week to acclimatize.
  2. The air temperature in the room should fluctuate between 10–30 degrees, and the humidity should be 40–60 percent.
  3. Heating devices should not be placed near the sheets.
  4. When working with furniture sheets, after each cut, coat the ends with varnish or wax.

Furniture board, regardless of the type of wood from which it is made, has a humidity of 10 ± 2%. Therefore, any wood before gluing into a furniture panel is dried. The furniture board you purchased is made of solid wood, in compliance with GOST 20850-84 and GOST 19414-90, dried in optimal conditions for this material. The moisture resistance of the adhesive joint has category D-3 (indoor use).
Those who purchase and use furniture panels for the manufacture of stairs, furniture and other wooden products may encounter a number of problems if basic storage conditions are not met. This is deformation (warping) of the shield and cracking at the ends. Wood is a natural material that is susceptible to environmental influences. The main reason why problems may arise is changes in humidity during transportation and storage in rooms with high or, conversely, low humidity. Depending on air humidity, wood can gain or release moisture. This happens until you coat your stairs (or other products) with varnish or oil.

Below are the basic requirements and recommendations for storing and installing furniture panels that must be followed:

1. All products must be packaged.

2. Do not unpack the furniture board immediately after delivery; it must “acclimatize” for a week at room temperature. It is especially necessary to adhere to this rule in winter, when the products are brought into a warm room from sub-zero temperatures during transportation, and problems will be inevitable if you immediately open the packaging.

3. Do not store furniture boards in rooms with high humidity, where “wet” repair work is being carried out, such as plaster, putty, or screeding.

4. The furniture board must be stored in a dry, ventilated room, stacking it horizontally on three or more transverse spacers. Two spacers must be placed at the edges of the canvas, and the rest in the middle.

After opening the package, treat the ends of the furniture panels with varnish, wax or oil. This procedure takes 5-10 minutes, but in the future it will save you from many problems. In winter, air humidity in heated rooms is very low, and usually no one bothers with purchasing and installing humidifiers. Almost all moisture release occurs through the ends of the furniture board (about 75%) and if the room is dry and hot, the board begins to crack at the edges. At the same time, one can often observe the fact that in the middle of the board the humidity is 10% (i.e. normal), and at the edges it is 5-6%, which certainly creates problems in the form of warping or cracking. The end processing procedure will avoid this. We recommend repeating this procedure in the same way after you have cut the furniture panel.

Installation rules.
1. Before installing the furniture panel, especially in winter, it is recommended to acclimatize the furniture panel in the room for a week.
2. The furniture panel is designed for installation in rooms with air temperatures from 10 to 30°C and relative humidity from 40 to 60%.
3. Do not leave furniture panels near heating appliances! Sharp fluctuations in ambient temperature can lead to the appearance of cracks and deformation of the furniture board.
4. Installation of a furniture panel in a room under construction or renovation can only be done if the room is completely ready; it must be dry. Both low humidity and high indoor temperatures should be avoided.

We can summarize the above with one more recommendation: buy furniture board in advance to give the product time to acclimatize.

If the rules of storage and operation are not followed, claims regarding the quality of the product will not be accepted, as well as for the final product made from furniture panels.

How to store furniture board? What to do after purchase

Why does the shield react to environmental changes?

Furniture board is a material that is highly valued by craftsmen and lovers of quality and beauty. Being completely natural, the material is highly susceptible to environmental changes. Thus, it is sensitive to storage conditions and can be damaged if improperly transported or used. As a rule, all problems that arise with the material are the result of sudden temperature changes and changes in humidity. Transporting solid wood in a cold car, storing it in a warm room - all this harms the material, making it vulnerable, as a result of which unevenness, cracks, and scratches can form on the wood. The tree quickly absorbs moisture, expanding, but if the air in the room is dry, the tree will release moisture and shrink accordingly. You can prevent the process from occurring quite simply; just treat the surface of the wood with varnish or oil, which will close the pores.

In order for the furniture board to remain in its original condition for as long as possible, it is enough to follow simple recommendations and put the following tips into practice:

  1. The furniture board must be carefully packed. Only in this case can you reliably protect it from scratches and also maintain normal ambient temperature.
  2. A furniture panel delivered to your home cannot be unpacked for a week. During this time, the material adapts to the temperature of the room, gets used to certain temperature conditions and changed humidity. This rule is incredibly important to follow in winter, when the difference in temperature outside and indoors can reach several tens of degrees. If this rule is violated, the furniture panel may become deformed and become unsuitable for further use.
  3. Furniture board does not tolerate high humidity, so it cannot be stored in a room where repairs are being carried out using plaster, putty and cement screed, the so-called “wet” building materials.
  4. In order for the shield to maintain its ideal shape and condition, it should only be stored in a horizontal position.
  5. After opening the package, it is necessary to cover the ends of the panels with varnish or wax to reliably protect the material. After the procedure, the shields must be dried indoors for one week. The fact is that the ends of the furniture board are areas through which active moisture loss occurs. In winter, when the indoor air is very dry due to heating, the release of moisture from the panel is especially intense. Uneven distribution of moisture leads to the fact that the product begins to warp and lose its attractiveness. The ends of the material should also be varnished after the shield is cut.

Thus, you need to plan in advance the purchase of furniture panels for stairs in order to prepare the material for work and avoid all the troubles. When carrying out acclimatization, it is important to ensure that the air in the room is not too humid or too dry. Using simple tips, you can avoid unnecessary expenses and prepare material for work, thereby saving time.