Wood is a very complex material and there are many variables controlling its properties. Differences in species and natural variations in grain pattern, density and the amount of sapwood/heartwood result in a certain amount of variability in the final moisture content. Still the averages can be applied. Timber is a type of solid lumber wood that offer exceptional structural qualities, but it also lends a warmth that can only come from the deep and rich grain of solid wood.
Drying lumber, either naturally (air drying) or in a kiln is the process to lower the moisture content. As wood dries, most of its strength properties increase. However, will continue to absorb or give off moisture with changes in humidity and temperature of the surrounding air. More humid air surrounding will cause wood to expand; drier air will cause wood to contract. This movement cannot be stopped. The greatest movement is across the grain. There is very little movement along the length. Movement across the grain is also greatly influenced by how a board was sawn. Furniture moved from one part of the world to another may change enough in dimension that it must be reworked to function correctly.
1. Composite/engineered wood
Plywood has a tendency to bend or sag in the middle when very lengthy pieces are used. Hence whenever the length of boards exceeds 7 feet or so, using blockboard is preferred. Blockboards are stronger but on the grain side but there rest of the sides are not strong at all (cannot hold screw). This is the reason why wardrobe doors, book shelves and panels are often made using blockboards. However, neither can we be sure if there are wide gaps inside the board, nor can we be sure of its strength.
Plywood quality 3-ply, 5-ply, 13-ply
- "MR" exterior grade Commercial ply (IS:303) - uses urea-formaldehyde glue and is "Moisture Resistant" for Interior work
- "BWR/BWP" exterior grade Commercial ply (IS:303) - uses phenol-formaldehyde glue and is "Boiling Water Resistant" for Exterior work. "FR" exterior grade Commercial ply - "Fire Retardant"
- Marine exterior grade ply (IS:710) - uses phenol-formaldehyde glue
- Structural ply & Film-faced (Resin Surfaced Shuttering) ply
2. Solid lumber wood
(less grain & does not stain as well because of high resin content)
Conifer generally covers and includes:
• Douglas fir
(It also includes woods such as cypress and manio, which are coniferous despite being hardwoods.)
- When shopping for new furniture, look at the back, inside and undersides of furniture and drawers. Many times it tells you more about quality than looking at the “show” side. The so-called “secondary” woods can speak volumes about the age of the item and the quality of construction.
- Please protect wooden floors by placing protective wooden felt pads on the bottom of your furniture legs
- Leave a 3cm gap behind any taller pieces to allow the air to circulate
- Semi-circular corners are odd when joined to the wall so, one end can remain curved but the other (touching the wall) should not be curved.
- (Imported Canadian) Birch or (White & Steam) Beech wood Rs 1600/cu.ft. used in plywood. It looks similar to maple but has narrower rays than those found in maple. If the birch is stained, it can be difficult to tell apart from cherry. It comes in variety of honey tones.
- Brazilian & African/Khaya Mahogany has a straight, fine and even grain, and is relatively free of voids and pockets. Its reddish-brown colour darkens over time, and displays a reddish sheen when polished. When it’s stained very dark, it can appear very similar to walnut. It has excellent workability, and is very durable. It is used to make cabinets and musical instruments to produce "warm"notes. It also resists wood rot, making it attractive in boat construction.
- Black Walnut is rated as very durable in terms of decay resistance, though it is susceptible to insect attack. This has occasional waves and curls. It is rarely stained.
- Maple or Sycamore - straight-grained, irregular & decorative wood grains pattern. Its very strong, heavy and has a high resistance to knocks but is prone to splits. It is usually not stained a dark colour, but is kept a natural whitish-cream or sometimes stained translucent amber-yellow. Its used to make paper with good printing properties.
- Elm wood is hard and has knots and burrs, interlocking grain and consequent resistance to splitting. Used in wagon wheel hubs, chair seats and coffins.
- Cherry - straight-grained, pockets of gum. Stained poplar (inexpensive) can be almost impossible to tell apart from cherry
- Lacewood is subject to a lot of confusion, both because it is widely called both lacewood and silky oak
- Gurjan or Keruing (imported from Burma, Indonesia, Malaysia). It is used as plywood core.
- Black Plum (Jamun/Nerale Hannu) - It is not to be confused with blackberry.
- Roble wood
- Neem or Margosa Rs. 900/cu.ft.
- Shorea (or Sal), also known under the trade names "Red Meranti" and "Lauan" used for door and window frame, wooden beam etc. It is not suitable for shutters and furniture. Merant is a mixed species grouping of the shorea. Its grouped according to their colour and density.
- Poplar is light and very soft used for packing cases and for making plywood. After conifers it's the principal source of cellulose for pulp paper.