From log... to solid wood!

Hello to everyone! Welcome back on CN's BLOG!
Today's post is about some technical feature: we're going to write about...SOLID WOOD.

What is solid wood? Usually this definition is used to distinguish between ordinary lumber and engineered wood. It is also known as lumber and it is made by the older part of the log, next to the center, that is called heartwood. Sapwood, instead, is used to produce veneer, as we have already seen here and here.

In order to became finished lumber, cutting a log isn't enough: there are special procedures that allow the wood to become more resistant over time and to the weathering.

After debarking, the wood can be sawn in different ways, depending on its size. This process requires a great attention, because the result should appear homogeneous and without cracks and knots. These are often visible in the core, from which the roughest material comes.
What are knots? They simply are what remains of old branches: limbs grow from the center of the log and when it grows too, new layers simply cover the start of these branches and form knots.


The sawing produces lumbers and boards, which measures are different in each country.
In Italy they are divided in different classes:
- Class A: sharp;
- Class B: round edge;
- Class C: chamfer.
Here nearby you can see the different cuts that lumbers and boards usually have.

But, before being sold, these pieces need to be treated.
We must say, indeed, that untreated wood (the log) has a 40-50% of moisture content! When wood is used as a construction material, il will absord or desorb moisture, in order to be in equilibrium with its surroundings. This equilibrium must be controlled to prevent damages: that's why wood must be dried to that equilibrium moisture. There are different ways of drying: natural (or air) or artificial. This process causes the wood to have around 20% of moisture content.
The loss of water causes the wood to become lighter and contract.

At this point, a different treatments start, to protect the wood from insects, fungi and molds. For this purpose, there are special chemical compounds or a particular way of drying, called KVH (Konstruktionvollholz), that, though a drying that reduces the moisture content to 12%, allows the wood to be ready to sell, without any other treatment.

Lumbers and boards are usually smoothed and cut at the edges, there is a selection and then they are marked and bounded.

Solid wood has some advantages:
- it is eco-friendly: it's a renewable material and for this and many other reasons is used in the green building.
- it lasts in time: it properly treated and if you take care of it, the material of first choice has a long life.
- precious: but also... expensive!
- resistant and flexible: wood is a "lining" material and can easily adapt to the surroundings.
On the other hand, you should be attentive to:
- choose very good and high quality material.
- choose a proper treatment.

A big problem of solid wood is due to its dimension: this could be solved thanks to the use of  laminated wood or using a finger joint.

VENEER MATCHING TECHNIQUES

Be glad, carpenters! Our rubric is back "on the blog"!

We must first resume what we have said on the previous episodes: we have written about how veneer can be cut and what is the process of veneering. But these sheets made out of wood can be smaller than your cupboard or table... So, they have to been matched. This matching process can be done with different methods, that can have different results.
Usually, sheets are sold in packs of 24/32 (it depends on the thickness and the type of wood). These packs are composed by veneer made out of the same part of the log, so they tend to have an homogeneous color.

One of the most common approach is called book matching: alternative pieces of veneer are flipped over, so they match as pages of a book. This kind of matching technique is used on flamed wood (obtained by lengthwise cut). 

This is one of the most precious finishing, due to its perfectly symmetric  pattern and its homogeneous color.

Another approach is the slip matching: 

sheets are simply joined in sequence, without flipping them. Wood with straight grain are often put together like this, so the joins will not be obvious.
Another reason for using a slip matching concerns the color: if sheets are flipped, the painting can have a different results on the different sides.
Transparent and natural finishing are usually used.

Then, we can write something about the random matching:

this technique is just what it sounds like; sheets are chopped and then matched, without respecting any kind of grain or color. The results is a bigger sheet that has a pattern composed by different colors and grain.

There are some other approaches, that creates particular patterns and figures: diamond, reversed diamond, sun, box... Each of these can give to your furniture a refined look and a different meaning!

La GIUNTATURA del TRANCIATO

Gioite gioite, amanti delle tecniche di falegnameria!

La nostra rubrica è di nuovo "on the blog", dopo un inizio anno un po' in sordina.

Ripendiamo il discorso da dove eravamo rimasti: il tranciato di legno, risultato della tranciatura, si adagia sui nostri mobili tramite il processo dell'impiallaccialura. Ma cosa succede quando il foglio non è abbastanza grande: facile, come già detto si passa all'aggiuntura, ossia alla giuntura dei vari fogli di tranciato tra di loro. I metodi con cui questo processo è attuato, saranno approfonditi in un prossimo articolo, per oggi ci divertiamo con le forme e i colori e vediamo come questi fogli possono essere assemblati.

In genere i fogli vengono venduti a pacchi di 24/32 fogli, dipendentemente dallo spessore e dal tipo di legno; questi fogli sono contigui, ovvero ricavati dalla stessa parte del tronco, sia esso il cuore (dal colore più scuro) o l'alburno (la parte più esterna e chiara).

Un primo metodo è quello detto a libro o cattedrale: il foglio di tranciato fiammato, ovvero quello con un disegno a fiamma, derivato da un tipo di taglio longitudinale, viene accostato ad un foglio con lo stesso disegno ma rovesciato. In pratica i due sono uno il simmetrico dell'altro. 

Questo tipo di aggiuntura è uno dei più pregiati.

Un altro metodo è quello di giunta a correre: 

i fogli vengono semplicemente accostati tra di loro, senza capovolgerli. E' una tecnica che si usa soprattutto per il tranciato rigato, in modo da ottenere un effetto omogeneo. Di solito vengono applicate delle colorazioni naturali a questi tranciati. Proprio per un problema di tinta, i fogli risultano girati tutti dalla stessa parte: girandoli sull'altra faccia, infatti il colore potrette risultare diverso.

Vediamo poi la giunta dogata:

il nome deriva dalle doghe del parquet e il foglio di tranciato in questo caso viene prima sezionato, poi giuntato senza rispettare un ordine o un disegno preciso. Il risultato è un foglio con un disegno misto, venature diverse e anche un colore disomogeneo. 

La casualità degli accoppiamenti gli è valsa il nome di giunta random, ossia casuale.

Ci sono poi molti altri modi per giuntare i fogli di tranciato, a seconda del disegno che si vuole creare, come a diamante, a diamante rovesciato, sole, scatola... Ognuno ha la sua particolarità e donano tutti un effetto molto ricercato ai vostri mobili.

Tutto chiaro? Alla prossima puntata!

Wood VENEERING

Here we go with the second technical articles, translated from this post. Today we are talking about the process off veneering, that is used to produce furniture that is resistant, nice and also less expensive that the one in massif wood. How does it can be possible?

First of all, you should have been read the article about wood SLICING, that will provide you a good explanation about the way we can obtain a sheet of wood.
Then, we must clear up the concept of veneering: this words refers only to the covering made by wood sheets (called veneer) and not to all kind of covering. Indeed, wood can be covered also by melaminic resins, but we'll talk about it another time.

Questions? Please feel free to pose questions on the comment area, under this post!
Now we can describe what happens to the sheet of wood. Once it is sliced from the log, it is dried up and sometimes also ironed, as your mother (or wife) does with your shirt, as there will be no unaesthetic pleats once you wear it.
These sheets undertake a docking and trimming, that means parallel and perpendicular cutting to make the edges uniform.



Now the veneer is ready to be joined one to another, to create bigger panels.
This laid-up veneer can be done in different ways, with glue on the edges or adding paper on the back of it. This last process is used to compose marquetry and it is also very useful when the veneer is applied on curved surfaces: in this way the wood is less likely to crack.
Anyhow, precision is essential. The pattern depends on the different lying up of sheets. Here you can see come examples.

These sheets are glued (with special kind of glue) on less-precious wood panels.

What about the result?
Stable and durable furniture, that resist better to woodworm attacks and are homogeneous when produced in series. Moreover, with an infinite choice of the patterns, that is limited only by our imagination (and technique progress). Some project can be realized only by using veneer, because the climate changes (hot and cold, rain and sun) cause a contraction and expansion of solid wood and this can compromise the stability of the furniture.

But, most important, wood veneering is ecological! Furniture made by wood veneer uses less wood that same pieces made by solid wood. Using wood requires 70% less energy than other materials.
Being eco-friendly means a greater possibility of recyclability and renewability, for a conscious and attentive use of wood resources.



At the end, some sort of curiosity: wood veneer was used since Renaissance. Obviously, they had no machinery like the ones we use today and, of course they sliced wood in thicker sheets.
This can be used to recognize the age of some furniture and avoid buying fakes!