Manufactured BoardsThe purpose of this lesson is to introduce the idea of

where manufactured boards are most usefully used.We will particularly look at the following boards which are in common use in today’s workshop.

•Plywood

Chipboard

Blockboard

Hardboard

MDF (Medium Density Fibreboard)

Sterling Board (O.S.B. Orientated Strand Board)

Modern techniques

Intro

Manufactured Boards

Q) Why are Manufactured boards often referred to as “Sheet Material? ”

Q) Who knows the most common size of sheet material ?

Q) What advantages do Manufactured sheet materials have over natural timber?

Manufactured Boards

Sheet materials cover a large area more quickly and economically than natural timbers.

Sheet materials can be much more stable in service than natural timber BUT ONLY IF USED CORRECTLY as we will see.

If a sheet material has been correctly chosen, a good finish can be obtained to give a long lasting finish.

If a good finish is not essential then there are sheet materials that can be obtained very cheaply (i.e.: Sterling Board)

Q) What disadvantages do Manufactured sheet materials have over natural timber?

M.D.F. and hardboards create a lot of dust which can become very hazardous when used in large quantities. Indeed there have been accusations of this dust being carcinogenic although this is yet to be proven.

If a non Moisture Resistant (M.R.) or W.B.P.

(Weather & Boil-proof) sheet is used in a moist atmosphere it will certainly warp or break down

Q) What disadvantages do Man Manufactured sheet materials have over natural timber?

Sheet materials can be awkward to handle in large sheet sizes of 2440mm and greater.

Some sheet materials can be very heavy to handle such as M.D.F., block-board and any sheet of 19mm thickness or greater.

The Modern process

The main features of Plywood are:

It is made by bonding alternating layers of timber veneer (softwood or hardwood) at right angles to each other.

It is supplied in a range of thickness from 3mm to 25mm, all of which will usually have an odd number of veneers as shown

The main features of Plywood are:

It is available in a variety of finishes from rough “sheathing ply” for outside work to a high quality interior grade Birch finish.

It’s grade: the term grade covers types of adhesives used , the durability of the veneers, the structural qualities and any possible coatings for special purposes) all these combined give the plywood its grade.

What are the main uses of plywood?

Panels, wall cladding, furniture manufacture,

floor covering, Roof decking, Shuttering.

What do the following abbreviations mean when applied to plywood bonding?

W.B.P Weather and boil proof

B.R. Boil resistant

M.R. Moisture resistant

Chipboards sheeting

It is made by chipping and grinding wood particles such as spruce, pines, firs to produce the materials needed.

Chipboard

The particles then graded and blended with adhesives and pressed before a final sanding process.

Chipboard

It is supplied in a range of thickness from 13mm to 22mm with sheet sizes as standard but also in (8ft x 2ft) with a tongue and groove for flooring purposes.

It is sometimes produced with plastic finishes or or hardwood veneers for kitchen units etc.

Veneer Cutting MethodsPlywood veneers are typically cut from the log four different ways. These cuts, or how the veneer is peeled from a tree, will determine the overall look of the panel in its completion. Below we show these different methods and describe how they are made.

Blockboard

Wood strip cores are produced from dried boards, previously cut from logs, they are first glued together to form a laminated slab then are clad on both sides with veneer to make up three or five ply

Blockboard

This has a core made up of glued laminations of narrow wood strips usually between 19 and 30mm wide.the overall sheet sizes being the standard.

Blockboard

The uses are similar to that of a veneered plywood, the main differences being their bonding and durability, the glue used in block board usually being a synthetic adhesive classified for interior use although this is not always the case.

HardBoard

Hard board is yet another of the wood waste products,the wood is pulped by machine,bonded with adhesive and finally pressed to a thickness of 3mm to 6mm.

Hardboard has many uses including panelling ,wall and floor covering.

HardBoard

The surface is very tough and can be very difficult to penetrate with panel pins.

For best results the hardboard should be wetted on its back side and allowed to dry before use to prevent distortion after fixing. This is known as conditioning.

M.D.F.

M.D.F.

Is made to conventional sheet sizes and thickness

varying from

4mm to 30mm.

M.D.F.

(Medium density fibreboard) this is also made from wood fibres glued together with synthetic adhesives.

This is used extensively in joinery manufacture as well as moulding of all shapes and sizes ( skirting, architraves etc.).

M.D.F.

M.D.F. Can be machine routed and finished to any desired shape or section, it can easily be worked with conventional tools.

A moisture resistant board is also available for external use.

O.S.B.

(Oriented strand board) this is widely used as a less expensive alternative to exterior grade plywood.

It is made up of wood strands glued together in such a way as to produce great strength as well as rigidity.

O.S.B.The strands are screened to remove dust and then dried in a tumble dryer they are then blended with powdered adhesive resin before being compressed to the desired thickness.

Sheet sizes are standard with thickness from 6mm to 25mm.

LaminboardThis is very similar to blockboard, except that the core strips are narrower, not exceeding 7mm in width.

The laminations are faced both sides with a facing veneer similar to blockboard.

Give some common uses for the following sheet materials?

Plywood

Blockboard

Chipboard

Hardboard

M.D.F.

O.S.B.

Interior wall lining, flooring, framing,window linings,Facia,barge boards (garages) (w.b.p)

Doors, table tops, counters, furniture, wall panelling,door blanks

Flooring, kitchen worktops, Kitchen units, general furniture, roof decking(low grade) general joinery

Flush door skins, backing for units, floor coverings, templates.

Mouldings, furniture manufacture, panels, Skirting, Architraves,

window linings, window sills, Laminate flooring.

Hoardings, cladding, packing cases, formwork, roof decking, board up material, temp cover protection for floors

Storage, Handling and Stacking of Sheet Materials

Storage

The method of storage will depend upon the type of sheet and where it is to be stored.

If the sheets are to be used and stored on site it is difficult to ensure that correct storage and protection is given.

In most cases, protection will be in the form of a plastic sheet covering. to ensure that sheets are not subjected to twisting and bending, and are protected from rain.

Stacking plywood

Sheet SizesThe table below shows some of the many sheet sizes available.

You will notice that the traditional common imperial sizes such as eight feet by four feet are sometimes available as their metric equivalent such as 2440mm x 1220mm sheets.

The nearest true metric size would be 2400mm x 1200mm.

Material Length (mm) Width (mm) Thickness (mm)

Plywood 1200, 2400, 2500, 3000, 3600 1200, 1220 4-30

Chipboard 2400, 2440, 2750, 3050, 3660 600, 1220 2.5-38

Hardwood 1220 to 3660 600, 1220, 1372, 1660 1.3-9.5

MDF 2440, 2745, 3050, 3660 1220 12-38

Blockboard 1220, 2440, 2500, 3050, 3660 1220 12-38

Laminboard 1220, 2440, 2500, 3050, 3660 1220 12-38

Material Length (mm) Width (mm) Thickness (mm)

Plywood 1200, 2400, 2500, 3000, 3600 1200, 1220 4-30

Chipboard 2400, 2440, 2750, 3050, 3660 600, 1220 2.5-38

Hardwood 1220 to 3660 600, 1220, 1372, 1660 1.3-9.5

MDF 2440, 2745, 3050, 3660 1220 12-38

Blockboard 1220, 2440, 2500, 3050, 3660 1220 12-38

Laminboard 1220, 2440, 2500, 3050, 3660 1220 12-38

OO

E

I

B

F

J

NN

G

K

A

HH

PP

Match-upMatch-upRecap