Have you heard of cross-jointed glulam made from oil oak?

When it comes to solid wood laminated timber, you're probably familiar with it. You might immediately think of terms like "horizontal jointing, longitudinal splicing, and finger-jointing," but the wood used for laminated timber is mostly small-diameter. The laminated timber we're introducing today is somewhat different in two key ways: the material selection and the joint structure.

Before introducing this new type of integrated wood, the author feels it is necessary to re-learn the definition of integrated wood with everyone. The focus should be on clarifying the differences and connections between integrated wood and finger-jointed wood. This is very important and will make it easier to understand the subsequent structural introduction.

Not all glulam is finger-jointed

In the academic field, the definition of glued lumber is as follows: "Glued lumber is a wooden structural board of certain specifications and shapes formed by gluing together solid wood boards or strips with parallel wood grains, lengthened or widened in length or width (some also need to be layered in thickness)."

From the above definition of glulam, we can see that its main process characteristics are "joining lengths, widths, and gluing." Some might say, "Isn't this just finger-jointed lumber?" This is true, as most glulam is finger-joined for lengths, with horizontal sections often flat-jointed. Therefore, when glulam is mentioned, many people immediately think of finger-jointed lumber.

In fact, the relationship between finger-jointed wood and glulam is inclusive, and finger-jointed wood is a type of glulam. Simply put, finger-jointing is just one of the ways to integrate wood, and it is not appropriate to generalize that all glulam is "finger-joined."

Horizontal concave and convex mortise and tenon-jointed integrated timber

Since finger jointing is not the only way to integrate solid wood, are there any other structural methods? Of course there are, such as the structure that uses concave and convex mortise and tenon joints that we will talk about next.

It is composed of two square bars with the same shape and structure. There is a tenon in the middle of the top of the wooden bar, and side tenons on both sides of the tenon in the top of the wooden bar. There is a mortise in the middle of the bottom of the wooden bar, and side tenons on both sides of the mortise in the bottom of the wooden bar. The structure of the square bar is as follows:

▲Square structure

Two square strips of different lengths but the same structure are cross-spliced ​​in a herringbone shape, so that the tenons and mortises, and the side tenons and side tenons of the two wood strips are matched one after another, forming a mortise and tenon inlaid structure. During the splicing process, the two wood strips are adjusted according to the required length of the board to carry out layout and cross-splicing to form an integrated material of arbitrary length and width. Since the wood strips are locked together as a whole, the formed integrated material is relatively stable and strong, adding a new type of integrated material for artificial boards.

▲Square bar integrated structure

This new structure retains the physical properties of traditional integrated materials, does not destroy the wood's tracheal fiber structure and the wood's natural lignin, and has a series of physical properties of the original wood, such as regulating indoor humidity and absorbing ultraviolet rays. Moreover, the individual square strips are relatively small, and the stress, expansion and contraction coefficient, and elastic modulus of the square strips themselves are relatively weak. In addition, a new mortise and tenon inlay process is used between the chord surfaces of the square strips, and the square strips are locked together as a whole, so the integrated material formed is relatively stable and strong.

In addition, the splicing and molding process can be completed at room temperature without the need for hot splicing, eliminating the use of urea-formaldehyde glue, and the finished composite materials have no special odor.

▲Actual photo of square mortise and tenon inlay

Glulam constructed from new varieties of oil oak

As mentioned at the beginning of the article, the integrated wood we are going to introduce, in addition to its special structure, the wood it uses is also quite interesting, called oil oak.

Oil oak, an evergreen tree, belongs to the genus Eucalyptus of the Myrtaceae family. It was cultivated and planted by Dr. Xiang Dongyun, who enjoys the reputation of "Father of Eucalyptus in China" and named according to the basic characteristics of the wood.

Oil oak is rich in eucalyptol, pinene, benzoic aldehyde, piperitone, water fennel and other natural essential oils that are beneficial to human health. It is also tough, dense in texture, insect-resistant and corrosion-resistant. It has excellent wood health and physical properties. Large-scale use in the living room has significant effects in refreshing the mind, stimulating the spirit, killing bacteria, anti-inflammation, disinfecting, and regulating indoor temperature and humidity.

However, due to its rapid growth, high density, and great variation in wood properties, it is difficult to process and utilize. So far, there is no precedent for large-scale production and utilization of solid wood at home and abroad.

The unique properties of oil oak make it a unique tool for creating a healthy living environment, unmatched by any other material. Its potent release of phytoncides and negative ions (vitamins of the air) is scientifically proven to kill airborne bacteria, curb human disease, and enhance immunity. They also have significant benefits, such as refreshing the mind, improving memory, lowering blood pressure, and calming the autonomic nervous system, resulting in a more pleasant mood. Their effects on regulating indoor temperature and humidity, resisting bacteria, purifying the air, and invigorating the spirit are gradually gaining recognition.

How does the performance of oil oak compare to other woods? For a more detailed analysis, please see the table below:

Oil oak mortise and tenon inlaid laminated wood furniture production

After introducing the structure and wood used for this new type of integrated material, you must be interested in its practical application in furniture production. Here is a set of examples of using oil oak inlaid integrated materials to make furniture.

You will notice that the furniture shown above are all colored, and some are also finished. Indeed, this integrated material with new structure and new material is itself a type of base material, which can naturally be painted and veneered.

▲Finishing effect

The above finished furniture or decorative panels look pretty good. Under the current conditions of increasingly scarce wood resources, the research and development of new materials based on the means of material selection, talent training, and structural innovation is an important direction for the sustainable development of the furniture industry in the future.