ROODEPARKMr.Swanepeol

Year: Prep 1 Section: Woodwork

Lesson 4: Materials

Date:________________

Important information

Solid timber is a natural material we get from cutting trees. Solid timber can be worked and shaped by hand or machines which makes it very versatile.

Advantages of timber:

It can easily be shaped It can easily be joined with woodwork joints, glue, screws and nails. It is durable. Timber, that is not as durable, can be easily be treated to increase

the durability. It has the ability absorb shock It has a high strength-weight ratio.

Disadvantages of timber:

The hardness of timber is limited. Timber shrinks and expands as water is released and absorbed by it. When small in dimension, it burns easily.

1. Solid Timber

Standard chipboard size

2750 mm

1830 mm

Thickness of chipboard 8 – 30 mm

Manufacturing of different types of furniture and many different wooden projects

Used in construction things like roof trusses, doors, window frames, kitchen cabinets, wood floors and more

Material such as hardwood and softwood logs, sawmill waste and other timber waste can be utilized for the production of chipboard. Chipboard is manufactured by adding a small percentage of adhesives and wet wood chips and then pressuring it into a board shape we buy at the hardware shop.

2. Chipboard (Particle Board)

Uses of solid timber

Wood chip and addhesive mixture after it has dried.

Advantages of chipboard

Cheaper than solid timber It is available in large flat sheets Chipboard doesn’t need a lot of preparation in order to use for a project

Disadvantages of chipboard

It is rarely used outdoors or at places where there is a lot of moisture. Chipboard swells when in contact with water.

Shelves, tabletops, built-in cupboards, cupboard doors, school desks etc. Melamine is a hard resin put on chipboard and this type of chipboard is widely

used to build kitchen cupboards.

A number of layers of veneer are glued one upon the other to create a sheet of plywood. Each layer is glued with the grain at right angles to the next layer.

3. Plywood

Uses of chipboard

Veneer layers

Veneer

Veneer is a thin slice of wood, sometimes thinner than 0.25mm

Advantages of plywood

Very strong Stable, does not warp or shrink Does not split easily when nailed Smooth uniform finish

Disadvantages of plywood

Edges require facings Repair and maintenance can be difficult

Furniture making Panelling, floors and roofs Sport equipment Aircraft propellers Music instruments Ship building Crates etc.

Standard plywood size

2440 mm

1220 mm

Thickness of plywood

3 – 32 mm

Uses of plywood

We call it PVE or cold glue. That means Polyvinyl Acetate Emulsion glue. This glue is used most of the time while specialised glues are available for specialised tasks.

Characteristics

White in colour High strength Long open time It is used at room temperature Suitable only for indoor use Is not water resistant Pressure must be applied and can take up to 8 hours Versatile Water-based Perfect for many day-to-day adhesive needs

Uses

Excellent for joining wood To glue felt and other cloth to wood To glue plastic laminates to wood To glue leather to wood To glue paper and carton

4. Cold Glue (PVE Glue)

In woodwork, screws are more frequently used than nails. Screws are made of different materials with different finishes.

Parts of a screw

Different slots on screw heads

5. Screws

Slot

Head

Shank

Screw thread

Tip

Square

Pozidrive

Phillips

Slotted

After you have fitted all the parts together you’ll need to finish your project by giving it a protective coat of either varnish or sealer.

A. Varnish

Varnish is a transparent layer that can be applied to wood. An endless number of types is available, each with its own characteristics. Good varnishes can serve as grain filling and sealer at the same time.

B. Sanding Sealer

Sand and sealer is a type of grain filler that dries fast. Grain filling is the process through which the grain of the wood with large pores, is filled. After sanding sealer is applied and has dried completely, a smooth sanding paper is used to flat the surface and then a layer of furniture oil or polish can be applied to give the surface a shiny finish and also helps protect the wood.

Learner activities

1. Label the screw.

6. Varnish and Sealers

Advantages of using screws as a fixative

Higher holding ability than nails Can be removed easier and with less damage than nails

Disadvantages of using screws as a fixative

More expensive than nails More difficult to insert than nails when you don’t have power tools

2. Name seven characteristics of cold glue.

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3. State if the following statements are true or false.

Chipboard is more expensive than solid timber

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Solid Timber has the ability absorb shock

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Veneer is a thin slice of wood, sometimes thinner than 0.05mm

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PVE Glue is water resistant.

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Repair and maintenance on plywood can be difficult

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Varnishes can serve as grain filling and sealer at the same time

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4. Name two advantages and two disadvantages of solid timber.

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5. Draw a neat sketch for each of the different screw heads and name each of them.