The technique of airdrying consists mainly of making a stack. This is normally carried out in winter, when the tree has less moisture content. In air seasoning, the boards are stacked and divided by narrow pieces of wood called stickers so that the air can circulate freely about each board. There are many ways of seasoning or drying timber, but only two methods have been found satisfactory, principally for economic reasons. Air drying airdrying is the drying of timber by exposing it to the air.
Ppt timber and wood products powerpoint presentation free. Oct 25, 2017 the term seasoning carries the meaning that the wood had been exposed to one or more seasons of weather. This is a process of natural seasoning of timber that gives good results with logs of freshly cut trees. The time required for this type of seasoning is 2 to 4 weeks. When the drying is done in a kiln, the product is known as kilndried timber or lumber, whereas air drying is the more traditional method there are two main reasons for drying wood. These chemicals inhibit the growth of fungi or insects over the treated wood for certain length of time. Natural seasoning is the process in which timber is seasoned by subjecting it to the natural elements such as air or water. Seasoning seasoning is the process of drying moisture from timber.
After that logs are taken out from water and are kept in open air, so water present in timber would be dried by air. Natural seasoning may be water seasoning or air seasoning. Felling, conversion and seasoning of wood engineers. When the logs are placed in running water, the sap from the cells can be easily washed out. Oct 10, 2016 methodsmethods seasoning aims at drying a set quantity of timber uniformly to the equilibrium moisture content required with a minimum of degrade in the shortest possible time. Find powerpoint presentations and slides using the power of, find free presentations research about seasoning of wood ppt. In the summer months, trees can have more then fifty percent water content. Water seasoning to remove the sapwood, the logs of wood are immersed in. The basic principle is to stack the timber so that plenty of air can circulate around each piece. This has to be removed beforemoisture 100 to200 per cent. During period, the flowing water drives away the sap pf wood it. In other words seasoning of timber means getting rid of the sap and. One of the best of these is to immerse the timber in water as soon as it is cut down, and after it has remained about a fortnight in water, but not more, to take it out, and dry it. There are two main ways of seasoning timber, natural air and artificial kiln.
Removal of wood sap immersing logs into water flow is called water seasoning. Types of defects in timber as a construction material. Neem among the wood species that could be examined, neem azadirachta indica stands prominent. Duringperiod, the flowing water drives away the sap pf wood it. Ppt timber and wood products powerpoint presentation. Air seasoning the easiest way, but not the most effective method of seasoning timber, is to stack it outside. Artificial or kiln seasoning is a quicker method of seasoning timber t the desired moisture content under highly controlled conditions. When the drying is done in a kiln, the product is known as kilndried timber or lumber, whereas air drying is the more traditional method. Seasoning is the process of removing the moisture content from wood to minimize structural problems when used in.
Scribd is the worlds largest social reading and publishing site. The water is to be removed before it used for engineering purposes. Oily substances insoluble in water watersoluble salts salts. Seasoning is the reduction of moisture content of timber to that of thesurrounding air sydney area approx. Salt water is considered best for shiptimber, but for timber to be employed in the construction of dwellinghouses fresh water is better. More than half the weight of freshly cut timber consists of moisture or sap. It is normally placed in a hut building, with two sides open to allow air to circulate.
The process of drying of timber is known as seasoning of timber. This can cause it to shrink but it helps to prevent warping, splitting, it will become lighter and stronger and it becomes easier to machine. In other words, the timber or lumber is air dried for about one year. On account of the time required to season timber in the natural way, various methods have been tried to effect the same purpose in a shorter time. Chemical or salt seasoning a water chemical salt, urea is applied to the timber for seasoning. There are 3 main classes of preservatives oily substances insoluble in water watersoluble salts salts carried in volatile solvent other than water.
Timber, lime, brick and mortar study notes for civil engineering. It is carried out on the banks of the river while thicker ends are kept towards. Seasoning of timber artificial water seasoning the logs of wood are kept in running water. It reduces the moisture due to the difference in vapour pressure of. Compartment kiln seasoning is an artificial process for removing moisture from timber. I have made money from other survey sites but made double or triple with for the same time and effort.
In water seasoning, timber logs are kept immersed whole in the flowing water. Good timber is free from defects like dead knots, shakes and cracks. Timber is seasoned to dry out the timber to bring it to a usable and workable condition. The water will affect timber in many ways, for example strength properties will be reduce fungal attack. In water seasoning, the timber balks are immersed in water for 1520 days. During seasoning of timber, exterior or surface layer of the timber dries before the interior surface. View and download powerpoint presentations on seasoning of wood ppt. If you mean lumber or boards, the lumber needs to be stacked in a way. Seasoning is the process of drying timber to remove the bound moisture contained in walls of the wood cells to produce seasoned timber. The preservatives may be water solvable salts or oil solvable salts or volatile base salts.
Care should be taken to see that timber is not partly immersed. Methods of natural air seasoning of wood timber how to do. Free powerpoint templates page 9 methods of seasoning natural. Seasoning timber is essentially just to drain it of water which is called its moisture content. Newly felled tree contains a considerable quantity of sap. Timber is a natural product, drawn from the wood in the trunks. It fre quently happens that in the sapwood, and sometimes in the heart wood, the weight of the water is more than the weight of the wood substance itself.
Felling, conversion and seasoning of wood engineers gallery. Good timber is one which is capable of resisting the action of fungi and insects attack defects. Find powerpoint presentations and slides using the power of, find free presentations research about timber ppt. Timber is taken out after a period of about 2 to 4 weeks. This has to be removed before the timber becomes fit for servicethe timber becomes fit for service water contained in wood is held in two forms. Seasoning of timber reason methods benefits civil engineering. Chemical seasoning of wood and preservation methods of. Ppt timber%20and%20wood%20products powerpoint presentation. Different types of defects occur in timber at these various stages. So unless you are going to raise a framed barn made from green oak you will need to season the wood. This is simply the weight of water contained in a piece of timber compared with the weight of actual woody substance in the same piece. Chemical seasoning consistsapply of hygroscopic or antishrink chemicals green timber soaked in chemical water to allow absorption up to 110th of total thickness of sawn timber chemical maintain moisture to reduce cracks chemicals.
Seasoning is the process of drying timber to remove the bound moisture contained in walls of wood cells, producing a new product called seasoned timber. The amount of water thus contained varies with the kind of wood, the conditions under which it grew, and the season. In place of sap, the cells get filled with ordinary water. Wood drying 1 wood drying wood drying also seasoning lumber or wood seasoning refers to reducing the moisture content of wood prior to its use. Seasoning is not always uniform in all the sections of timber. Different ways of seasoning wood home guides sf gate. Woodworking when wood is used as a construction material, whether as a structural support in a building. Progressive kiln compartment kiln electrical seasoning in this method high frequency alternate electric current is passed through timber. So, stress is developed due to the difference in shrinkage. When timber is put in water it must be sunk so as to be completely under water, as nothing is more destructive than partial immersion. The purpose of seasoning is to dry the timber from its raw wet state to a dry state, which makes it workable and less prone to decay in the form of rot fungal.
Timber pieces are immersed wholly in water, preferably in running water of a stream. This method is also called air seasoning timber seasoned by this method is left outside to dry for many months the timber is stacked on large planks of timber, these planks are stacked on blocks. Ppt seasoning of timber powerpoint presentation, free download. From this method oftreatment, it hasbeenfound outthat at lowell, mass. The roof and two other sides keep the timber relatively dry. The stack is slanted to facilitate drainage of rain. If this sap is not removed the timber is likely to warp, crack and shrink. Water seasoning is the process in which timber is immersed in water flow which helps to remove the sap present in the. A oily preservatives coaltar is the best known most widely used preservative obtained from bituminous coal available in many grades gives satisfactory results. The durability of timber can be considerably increased by treating it with certain chemicals, grouped together as preservatives, before use. May 11, 2007 seasoning is the process of drying timber to remove the bound moisture contained in walls of wood cells, producing a new product called seasoned timber. The felling of a tree, is the first stage of preparing the timber for commercial use.
Wood from freshly felled trees contains a large quantity ofwood from freshly felled trees contains a large quantity of moisture 100 to200 per cent. Research carried out by radwanski 1969 in sokoto northern nigeria revealed that azadirachta indica is a fast growing tree which can be planted in arid regions as it is not requiring irrigation. The different ways that seasoning in wood can be achieved. Woodworking when wood is used as a construction material, whether as a. The blocks stop the timber absorbing water from the ground the timber is covered by an over hanging roof.
In general, the defects in timber are mainly due to. The timber is stacked with wide spaces between each piece horizontally, and with strips of wood between each layer ensuring that there is a vertical separation too. Seasoning is the process of removing the moisture content from wood to minimize structural problems when used in construction or to provide less smoke and more uniform combustion when used as. You have probably heard the term green timber or bleu in france but this timber can contain up to 50% water, you might have been told hydration is good but with the timber not so great.
Dec 23, 2015 removal of moisture from timber so as to be in equilibrium with moisture in surrounding atmospheric condition, where timber is likely to be used is called as seasoning of timber. Before reaching this final stage, timber comes across many critical stages like growing without defects, cutting at the right time, seasoning, converting and using. The term seasoning carries the meaning that the wood had been exposed to one or more seasons of weather. Timber types of woods, plywood, veneer, laminate, blockboard with market su. The colouring matter in timber is often partly soluble in water, and this is a common cause of difficulty. Wood drying also seasoning lumber or wood seasoning reduces the moisture content of wood before its use. Timber is then taken out and driedin open air for about a month. The timber is laid out as seen in the diagram below. Timber, lime, brick and mortar study notes for civil. Seasoning of timber when a tree is newly felled, it contains about 50% or more of its own weight as water. The art of seasoning of timber is to extract the moisture under controlled conditions as nearly as possible at a uniform rate from all parts of timber and to leave the remaining moisture, that cannot be extracted. Water seasoning takes less time than air seasoning, but the strength of wood is reduced. Seasoning can be achieved in a number of ways, but the aim is to remove water at a uniform rate through the piece to prevent damage to the wood during drying seasoning degrade.
This document has been scanned from hardcopy archives for. During seasoning, a proper gap between logs should be maintained for. Water seasoning is the process in which timber is immersed in water flow which helps to remove the sap present in the timber. Faulty method of seasoning causes serious defects in woods. If the water is stagnant then the same should be changed at least once fortnight so as to remove the fermenting material. Timber is then taken out and dried in open air for about a month. The objective is to explain timber water seasoning in 2min whilst being creative about it. Removal of moisture from timber so as to be in equilibrium with moisture in surrounding atmospheric condition, where timber is likely to be used is called as seasoning of timber.
In a perfect seasoning process, stress is kept minimum by controlling the. A free powerpoint ppt presentation displayed as a flash slide show on id. Aug 28, 2016 preparation of timber after seasoning vincent ryan. Introduction to timber version 2, january 2010 1 of 3. To improve structural performancea prerequisite to the allocation of seasoned timber strength sd and joint groups jd is that the average moisture content in the piece be no more than 15%. Preparation of timber after seasoning vincent ryan. Seasoning timber wood, water, air, seasoned, products. The water is to be removed before the timber can be used for any engineering purpose.
Seasoning of timber or drying of wood wood drying also seasoning lumber or wood seasoning reduces the moisture content of wood before its use. Timber ppt free download as powerpoint presentation. Seasoning of timber from day to day, most people have some contact with seasoned timber. Seasoning is the name given to the methods of drying timber there are two methods by which timber can be dried. Seasoning of timberartificial water seasoning the logs of wood are kept in running water. The process of placing timber logs in water is sometimes referred to waterseasoning. When the surface of the timber is wetted, there is a chance that the colour will migrate and cause watermarks when the wood re. Seasoning of timber fresh timber contains about 50% or more of its own dry weight as water. During this period, sap contained in timber is washed away by water. Seasoning of timber and drying of wood types and methods. Seasoning can be achieved in a number of ways, but all methods aim to remove water at a uniform rate to prevent damage to the wood during drying seasoning degrade.
71 1162 934 425 438 176 562 894 157 1368 729 197 1441 1582 1232 203 1589 1322 1392 1658 603 1642 1505 1387 1231 593 1355 1418 15 732 861 967 509 880 1477 1257 1171 373 228 659 683 233