Introduction to various types of wood (part 2)

types of wood

In the previous part of this article we reviewed various types of natural woods and explained about factors that affect the formation of wood texture. In this part we will overview the human made and synthetic wood types.

Wooden products

Wooden products or “synthetic” types of wood are processed under a series of regulations to deliver a final product better than the original material. Processed wood in the workshop environment is subjected to a variety of actions, such as heat and pressing, to create a product different from the natural raw material, depending on the purpose of the product. There are different criteria such as thickness, resistance to external factors, weight, beauty, strength so that the workshop can decide exactly what to do on the original wood.

These woods are usually made with disposable materials that do not work with carpentry workshops based on size and thickness. The wood raw material, by combining other intermediate materials, is pressurized to form the final board product. The following classification is based on the shape of the material used:

  • If the resulting board is produced by putting together thin layers of wood and forms a set of layered compression plates, this product is called a layered board. Multilayer boards are another name for this product, which is named after the number of layers in the cutting board.
  • When wood chips form the main board instead of wood layers, the product takes on the name chipboard. The texture of this board is not composed of layers mounted on top of each other, but of small and large pieces of wood that are visible to the naked eye.
  • If the board is made of wood fibers, it gets the overall name of the fiberboard. Fiberboard itself is divided into different types. LDF, MDF and HDF are types of fiberboard.
  • If we use only wood flour or powder instead of wood fibers or wood, we naturally need another supplement to form the board. The second material used is plastic, and for this reason, the name of the product made with wood flour under heat and press is plastic wood or polywood.

Multilayer board

Since the plywood is made of multi-layered wood with adhesives, it can be trusted to a considerable extent and its range of application can be expanded. In fact, in this product, thin wooden layers have formed a thicker layer, and the overall thickness of the plywood means the total thickness of its forming layers. To maintain the strength of the board as much as possible, the layers are stacked perpendicular to each other based on their fibers to reduce the risk of breakage. The number of layers used in these boards varies depending on the application. This board can be made of different types of wood at different prices. The large size of these boards makes them work faster. Also, this wood is perfectly suitable for all kinds of drilling and sawing and other operations to be able to turn sand into any tool.

Chipboard

To become a wooden board, this product requires a material that acts like glue and sticks the pieces of wood together to form a single board. The material chosen for this purpose is resin or wax. The wood density of this board is high, but it is known among wood boards as the weakest and lightest board. Chipboard usually does not have a cover and is used in the same raw form for places that are not visible. Sometimes different covers or colors are used to make the board more beautiful. The coatings used for chipboard include natural wood veneer, synthetic veneer as well as glazed or varnished. Natural veneer that is natural and genuine wood; Artificial coatings are used in different colors and designs; The varnish is one or more coats of paint, which is responsible for the chemical protection of the chipboard. The board’s resistance to water and moisture is very low and can be a problem.

MDF

MDF, which stands for Medium Density Fibreboard, is a medium-density wood composite. That’s why it has the word medium in its name. Like chipboard, MDF is made from waste and wood fibers, but is much stronger than it is. A cross-section of the MDF shows a rough texture and shows what material the board is made of, but wood chips, unlike the chipboard, are not visible to the naked eye in the MDF. MDF can also be supplied with a variety of coatings. Fiberboard with a specific gravity or density higher than this HDF and with a specific gravity lower than this is called LDF.

HDF

The composite of HDF fiberboard, which stands for Hard Density Fibreboard, is named after its high wood density. The same MDF features are true for this board, but the only difference is that it has a higher density than it does. Higher temperatures and pressure are required to make HDF, but in some cases less adhesive is required. The result of this heat and high pressure makes the HDF highly resistant, which sometimes ends in a high price. The high density of this board increases its machining and tooling capabilities and creates better mechanical and physical properties for this board.

LDF

Unlike the Low Density Fibreboard, the LDF, unlike the HDF, has a low wood density. Like MDF and HDF, LDF is available in a variety of thicknesses and coatings.

Plastic wood

Plastic wood or WPC wood, which stands for Wood Plastic Composites, is made from a combination of flour and plastic or thermoplastic. Recycled materials are used to make this type of board; Both the plastic used in it is recycled and the wood waste is used. Finally, this green product itself can be recycled.

ThermoWood

Thermowood is the natural wood that is heated to change the cellular structure of the wood. Of course, heating has always been done to increase the strength of natural wood. This heating allows the thermowood to acquire positive properties and characteristics that either the natural wood did not have or acted poorly on. These properties, which are not present in natural raw wood, include resistance to decay, resistance to insects, resistance to moisture, high durability, and non-expansion and non-shrinkage. These features allow thermo wood to be used in exterior construction and parts of buildings such as roof gardens or swimming pools without any restrictions.

Introduction to various types of wood (part 1)

types of wood

In the first part of this article we will go through natural types of wood and their features and in the second part we will review the human made types of wood that are available in the market for various applications.

There are obviously various types of wood in nature but depending on the region, climate, vegetation, soil type, economic and political conditions and more elements, each region has a limited number of wood types. There are also many criteria for the classification of natural wood, but generally, in terms of the type of tree, the wood can be divided into two general categories: wood of broad-leaf trees and coniferous tree`s wood. Of course, there are trees that do not fall into either of these two categories.

Broad-leaved trees wood

The broad-leaf trees, as their name implies, have leaves that have many shapes, textures, and patterns in terms of surface area. These types of leaves are more diverse, and as a result, they have trunks with various textures than needle-like trunks. A general rule cannot be considered, but typically, broad-leaves trees have a harder wood. These types of wood have a more complex tissue structure, and drying these types of wood requires more complex processes.

Needle Tree Leaves wood

These types of trees have a simpler wood structure. The wood of these trees is softer, but this has nothing to do with their resistance. As a result of their softness, they are highly resilient and sawed. Of course, in addition to this, the many knots of leaf needles cannot be pleasant for many people in appearance and sometimes reduce the resistance of the wood to a small extent.

Age, ductility, longevity, moisture, porosity, fiber length, knots, softness and hardness, cracks are some of the criteria used to select wood, and wood is processed accordingly.

Softwoods

The softness of a wood does not mean that it is weaker. These trees are obtained from coniferous trees such as cedar, spruce and pine. The softwoods used for construction are mostly grown in cold regions, and the color of these woods usually turns yellow or red. Because coniferous trees grow fast, the price of these types of wood is lower than hardwoods. Also, it is easy to find soft-growing woods somewhere other than farms, and this does not lead to deforestation.

Hardwoods

Many carpenters or even cabinet-makers are more interested in working with hardwoods. These types of wood provide these people very stunning colors, designs and textures. Of course, the disadvantage of hardwoods is their high price, which cannot be applied for every application.

Environmental factors affecting the formation of wood texture

There are also unforeseen events that affect the texture and structure of the tree trunk

The natural behavior of trees is to grow and rise vertically relative to the earth’s surface, but in some cases this behavior changes due to different weather conditions and natural events. For instance, wood may be damaged by strong winds and bend and continue to grow bent. This wood is called a reaction wood and consists of two special types of wood that have happened in their stem. Reactive wood is made differently in broad-leaves and needles, and has different letters: tensile wood, which occurs in broad-leaf trees due to lack of oxygen, and compression wood, which occurs in coniferous needles. The reaction is caused by an excessive amount of oxygen.

The wood in the curved trunks of the trees shows itself in such a way that the wood-forming rings are more concentrated on one side. This means that if we make a cross section of the trunk of these trees, the rings do not start from the center and are not symmetrical and focus more on the right or left. This also happens in branches branching. To eliminate this and the ability to use this wood, discarded waste is increased.

Bending of wood can be based on external factors such as strong winds, the weight of snow or even the weight of the branches of the wood itself. Internal factors are also effective in bending and reacting wood. E.g. the cell wall may have the power to direct the growth of the trunk. The tensile strength of the new cells and the side of the wood is resisted by the older cells that are in the wood core, and this can cause the trunk to bend. Australian eucalyptus trees are one of the highlights of this event. This type of stretch wood, like compression wood, is not the best choice.

Natural wood versus synthetic or human made wood products

The originality and naturalness of wood products and structures is highly valuable, but the constant support of these products does not seem to be possible for natural and political-economic reasons. Nature destroys this amount of wood demand in terms of production, and trees alone need more to survive than in the woodworking industry. It is better to have a trunk of wood under the branches of a tree than in buildings. At the same time, wood has its drawbacks, and in terms of erosion and insects, it needs care and repair

Please read the second part of this article here to find out more about synthetic and human made wood types and products.