Independently there is in lesopilenii and derevoobrabatyvajushchej to the industry a plywood manufacture. Distinguish two kinds of plywood: single-layered nozhevuju (facing) and multilayered kleenuju. The first, intended mainly for krasnoderevnyh painting and decorating, is produced from valuable breeds of a tree. The scope kleenoj plywood is almost boundless.
Besides for the sake of convenience we will agree to name nozhevuju plywood irrespective of a way of its manufacture decorative, and kleenuju - simply plywood.
There are many ways raskroja trees of valuable breeds on thin plates, sheets of the decorative plywood, excluding the big losses of raw materials. The most ancient ways are a splitting and lushchenie. In the first case on special machine tools with clamping devices a piece of the log cleared of a bark, split, split, as kolunom fire wood, on a part along fibres. Up to the end of XIX century in such a way received plates, laths and rejki mahogany and other import breeds. To sawing up resorted seldom as the expensive sawdust managed. And here the way lushchenija is applied everywhere and today. It consists, that the piece of a log fixed in lushchilnom the machine tool, rotate round a longitudinal axis, and are motionless, the knife cuts off layers on annual rings. A log preliminary steam out. As a result receive sheet of decorative plywood of the set thickness, it is rare bol 1,5 mm, width depending on diameter of a trunk.
As annual rings never happen geometrically correct, strictly concentric, lushchenyj the sheet usually includes parts of several year rings. However this circumstance should be regarded as positive - the structure of decorative plywood turns out more picturesque. This way undress the Karelian birch, a maple, a nut and some other breeds of a tree. The way lushchenija vpoldereva at which cuts become in parallel a log axis, but not on a circle, and diametrically to it is applied. In this case on plywood drawing not several, and almost all year layers which quantity decreases in process of removal of a cut from the centre turns out. Conic lushchenie gives cuts like a shaving in the machine for mechanical sharpening of pencils on a cone.
The way wavy Is interesting are sharp (planing) of decorative plywood. In this case lushchilnye knifes sharpen wavy and the wood structure comes to light more full.
Thus, from the same piece of a tree it is possible to receive various on a structure plywood sheets (fig. 2) depending on under what corner to fibres and year rings is made cutting.
the Structure of decorative plywood from one piece of a tree:
1 - at a semiradial cut of a trunk; 2 - radial; 3 - tangential
Decorative plywood arrives on furniture factories packed into packs from the sheets received from one tree trunk, the same way of cutting or lushchenija, hence, with identical drawing. And in shops where there are departments "-С‹В skilful РЃС•СЉ" furniture factories hand over for sale a waste of decorative plywood also in packs (such pack is called knolem), usually till 10-15 sheets in everyone. The difference consists only that for furniture furnish half-number sheets in length to 1,5Рј and from 80 to 400 mm are used width, and on a share of fans of joiner's business there are scraps of these big sheets, however, quite sufficient on the size and good on quality, suitable for the majority of homeworks.
Just as carpenters distinguish the right and left parties in a board, and the cabinet maker distinguishes in thin sheet of decorative plywood obverse (right) and not obverse (left) the parties. Circumstance so important but to define, where the person and where a wrong side, hardly, especially if you deal not with krupnoporistoj oak plywood, and with melkoporistoj apple-tree or pear wood. In the packs of decorative plywood got in shop ordinary at face edges there are factory labels in the form of strips of a condenser paper. They happen exclusively on a face sheet.
Arrange plywood sheet before eyes so that beams of a strong light source of drop on it not steeply, and at an acute angle. On one surface you will see bugorki wood fibres is a face sheet, on another - small hollows, it nelitsevaja.
During veneering of products, i.e. In the course of pasting of a surface by decorative plywood, sheet put nelitsevoj, a wrong side downwards. Becomes so for two rather essential reasons. First, the party with bugorkami is easy for levelling at definitive furnish of a finished article by a grinding skin or tsiklej. To make smooth not obverse surface with hollows very difficultly, it will be necessary to remove a skin a thick layer of wood. Secondly, during a label bugorki a face sheet will prevent dense prileganiju decorative plywood to the basis. On the contrary, hollows will be filled with liquid glue, prileganie there will be uniform, a durability sklejki reliable. .
Kleenaja plywood is issued by factories in the big sheets and thickness 2, 3, 4, 5, 6, 8, 10 and 12 mm accordingly from three and more layers thin (no more than 2 mm) nozhevoj plywood - an interline interval. Two-layer plywood does not happen. On inside layers thicker interline interval from invaluable and low grades of wood of a fur-tree, an aspen, an alder more often is used. Fibres of an interline interval of different layers settle down perpendicularly to each other. Such arrangement of layers does kleenuju plywood very strong. In manufacture of furniture it is not only finishing, but also a constructive material. The plywood processed on gidropressah, does not concede on durability to sheet metal, it use at building of easy planes and boats.
The Best grades of plywood with one or from both parties are revetted with an interline interval of more valuable breeds of a tree. But if the plywood sheet is stuck together from an interline interval of one breed, more often birches and in this case one of the sheet parties will be more smooth, pure, without dropping out knots, roughnesses and other defects. It should be considered before solving, what party of plywood to make obverse.