Furnace: types, cutting methods, uses

Of all the forms in which wood can be found, veneer is the least presented. It is used for aesthetic reasons, to give a more pleasing appearance to wooden slabs that are not doing well in this respect, but also to increase their strength and durability. Product and interior designers have been discovering it for some time and using it for lighting fixtures or striking interior decoration. Next, more about veneer, getting the design right by cutting, older and newer uses.

History

For those who think that the veneer is a modern invention, they are wrong. Veneered objects have also been found in Egyptian tombs over 4000 years old. More modern evidence of the veneer comes from the 17th century, when better tools made it possible to cut slices of wood of different thicknesses.

In the 18th century renowned furniture manufacturer Chippendale used exotic veneers to increase the value of his furniture. In the early 19th century plywood made from 'slices' of wood was used in the USA to make pianos.

The first patent for veneer dates back to the mid-19th century. Rapid industrial development at that time made plywood a very affordable material by the end of the century.

Nowadays veneer is used both for plywood and for veneering wood-based boards. High demand for furniture combined with price pressure has led to the emergence of veneer-imitating foils and a whole industry of veneered panels. My view is that wood can be copied, but not replaced. Wood offers much more than just a design.

Types of veneer

Depending on the use, there are two broad categories of veneer:

• aesthetic veneer
• technical furnishing

Aesthetic supplies are those used to veneer the panels of PAL, MDF, panel, plywood, solid wood. They are very thin with thicknesses ranging from 0.55 mm to 1.2 mm. The harder and less porous the species, the thinner the veneer can be cut.

- Walnut, which has high density and very low permeability, can be cut to a thickness of 0.55 mm.

- Species with medium or low density and not very high porosity, such as anin, cherry or poplar, is cut in thicknesses of 0.6-0.7 mm.

- Oak and ulmul are hardwoods, but have very large pores. The veneers of these species are 0.7-0.8 mm thick.

- The resinous veneers, quite loose and porous, are 1.0 mm thick.

- Aesthetic veneers can also be obtained from parts of the tree which, due to growth defects, give a spectacular design. This is the case for roots or buboes (burlYou've certainly heard of, if you haven't seen, walnut root veneer. These veneers are a little thicker than the veneers cut from the trunk of the same tree. In the case of walnut, the veneer in the root is 0.6 mm thick.

Technical supplies are the ones from which the plywood is obtained. There are thinner face veneers (0.5-1.5 mm) and core veneers between 1.5 and 3 mm thick. Plywood is a wood-derived panel made from an odd number of veneers laid perpendicular to each other. The greater the number of layers, the stronger and stiffer the plywood becomes.

Plywood can be veneered with aesthetic veneers of other species and is thus used in furniture production. It is lighter compared to chipboard or MDF.

How to obtain

Supplies can be obtained from the trunk of the tree, the thick branches growing immediately from the trunk, the root and the berries. If aesthetic veneers are obtained, the wood is carefully selected according to size, age and visual characteristics: colour, pattern, species, characteristic natural marks or defects. This selection and the way the cutting is done influences the design of the veneers.

Veneer is mainly cut from hardwood because it is harder, denser and less permeable. Veneer is also made from softwoods, especially the harder ones.

The stages through which the log passes to the veneer stage are:

• peel
• cut to length
• plasticisation (steaming, wetting)
• debit
• drying
• cutting to size

In order for veneer sheets to be cut without cracking, the wood must be as plasticised as possible. This is done by wetting and steaming it. The length of time the logs stay in water and steam depends on the species and thickness. To produce a quality product, processing must be done fairly quickly - within an hour - after the logs are removed from steaming. Plasticizing can also be done with high-frequency currents (HFC), but few use it because it is an expensive process.

There are 4 main types of veneer production:

• by scrolling
• by tangential cutting
• by radial cutting
• by radial parallel cutting

Via running technical veneers are obtained. Virtually the entire log is rotated in line with a knife resulting in a continuous sheet of veneer. The sheet has no particular pattern, the cut being parallel to the annual rings. The method is very economical, with minimal losses. After unwinding, the sheets are cut to the desired size and dried.

There is also a method by which half logs are "unwound". The half is mounted on a device that rotates by passing through a knife. The result is veneer sheets that are larger than other types of cut, but smaller than the classic scroll and with a more rounded cathedral grain pattern.

Tangential cuttingis parallel to the centre of the log. The result is those flanges I mentioned above, but sharper. They are highly prized veneers for their specific natural design.

Radial plane cuttingThe knife is mounted at a 90° angle to the annual rings. The result is a pattern with parallel lines, the lines representing the annual rings.

Radial cuttingis made approximately the same as the flat one except that the angle is not exactly 90°. It is a specific oak cut, which highlights the medullary rays that appear as mirrors.

After cutting, the veneers are dried because the moisture content of the wood is increased by the plasticising treatments. They are then cut and stacked in bundles. In order to know where they come from and to be able to mate them, the wood is always numbered. So, in the end, the veneer bundles are made from the same piece of wood.

Use of veneers

Veneers ennoble wood-based panels. They are mostly used for veneering chipboard or MDF panels. But not only for them. It may seem strange, but solid wood panels are also veneered. There are situations when this is needed to make furniture pieces easier to use. For example, a large piece of oak or another high density wood is very heavy.

About plywood I want to emphasize that it is preferable to other types of panels because it is composed of several layers of wood. It looks good, it is easy to process and finish, it can be veneered with special woods, and it is much lighter than chipboard or MDF.

Supplies are used to obtain inlays. In the past it was a technique used to embellish pieces of furniture. Now, as it is a very painstaking operation and requires a lot of care, few people dare to do it anymore. Especially since the advent CNCs made it easy to "draw" various designs on wood without much effort.

Defective veneer results in reconstituted veneers which I have spoken about on another occasion. The difference between them is visible to a connoisseur, but it's still wood in the reconditioned one.

Their very beautiful natural design, the distinctive colours and the fact that they can be easily shaped has drawn designers' attention to veneers. That's how lighting fixtures with veneer lampshades came about. And they didn't stop there. They used them to decorate ceilings, create screens or decorate walls. Such veneers are treated to make them more plastic or easier to shape.

A very spectacular type of veneer is used to decorate jewellery boxes using the Japanese Yosegi technique. The resulting veneers have very different patterns and are as thin as a thin sheet of paper. But more about Yosegi Art in a future post.