The material used for making door and window

DOORS AND WINDOW
Some material used for making door and window

Different forms of commercial wood

1. Plywood
2. Veneer sheet
3. Blockboard
4. Batten board
5. Particleboard
6. Novapan
7. Sunmica

Plywood

• Some meaning of course ply is a thin layer.
• The plywood boards which are prepared from thin layers of wood in odd numbers are placed one above the other with the direction of grains of successive layers at a right angle to each other.
• The placing of veneers normal to each other increases the longitudinal and transverse strength of plywood.
• The face of plywood which has better finishing is known as the face and other exposed face as the back of the plywood. The plywood is generally manufactured in 3 plywood, 5 plywood & so on.

Advantages

• It shows very little expansion or shrinkage due to variation in moisture content.
• They are light & available in large sizes.
• They are available in decorative design.
• They are not liable to split or crack.
• They are very easy to work.

Veneer sheet

• Certain are thin sheets of wood of superior degree.
• The thickness varies from 4mm to 6mm or more.
• They obtained by rotating logwood against a  sharp knife rotating cutter or saw.
• Veneers after being removed, dried in kilns to remove moisture.

Blockboard

• They consist of a core made up of small timber blocks up to 25mm thickness fixed together edged to edged.
• Both the faces are lastly covered by plywood of 3mm thickness.
• The direction of grains of the core is at right angles to that of outer plies.
• These are cheaper than lamin boards & are used for partition & doors etc.
• Usual thickness is 12mm to 50mm, length varies from 1.2m to 2.4m & width from 90cm to 1.2m. 

Batten Board

• These are just like blockboard in construction except that core is made from timber blocks of width up to 8cm & 2-3cm thick.
• These boards are used for door panels, tabletops & another flat surface.
• The direction of grains of the core, battens are at right angles to that of adjacent out ply sheets.
• Both are light and strong and do non crack oppositely split easily.

Sunmica

• Sunmica is a kind of impregnated timber.
• Any timber which is fully approximately partially covered with resin is called as impregnated timber.
• Some usual resin employed does phenol-formaldehyde which remains soluble in water.
• The veneer either thin strips of wood are taken and placed between wood cells and by chemical reaction a consolidation mass-developed.
• It is then cured at a temperature of above 150° C to 160° C. The impregnated timber is available under trade names such as Formica, Sunglass, Sunmica, etc. & it is used for furniture, decorative materials, etc.

Advantages

• It is not affected by moisture & weather conditions.
• It is strong & durable.
• It resists the acidic effects.
• It possesses more electrical insulation.
• It prevents a decent appearance.
• The contraction & expansion of impreg timber is about 25-40% less than ordinary timber.