sactas12.weebly.comsactas12.weebly.com/.../6/8/14686550/12ittf_theory_d… · Web viewIn Sydney the EMC is 12% moisture content. Methods of Sawing Timber for Distribution Once a tree

Timber Properties

The Structure of Timber

Sapwood Is usually light in colour and contains living cells. The sapwood has 3 roles: Support, conduction and food storage. The cells in the sapwood are more open and this allows it to be easily treated.

Heartwood The fully matured wood which surrounds the pith. It is usually darker because of the hardened lignin and minerals in the dead cells. The cells in the heartwood are more closed and therefore make it harder to treat. The only role of heartwood is to support the structure of the tree.

Cambium Layer An outer layer on the tree which is responsible for growing outward throughout the year. This grows at different rates throughout the year depending on the season. As it grows out it leaves ‘Growth rings’.

as the seasons cause lighter and darker cambium to form known as ‘earlywood’ and ‘latewood’.

Growth Ring Growth rings within a tree generally represent 1 year’s growth and are formed in a pattern from the centre towards the outside of the tree. A growth ring is made up of two types of wood, earlywood and latewood.

Earlywood Formed during the Spring this part of the ring is wider and less dense. Latewood Formed during the Autumn this part of the ring is narrow and dense. Xylem An outer layer of the tree which transports water and minerals from the soil

up the trunk to parts of the tree to provide energy for growth. Phloem A very outer layer on a tree (right underneath the bark) which moves water

and sugars produced during photosynthesis to parts of the tree to provide energy for growth.

Bark Contains dead materials serving to protect the living inner back (Phloem).Photosynthesis Involves the plant transforming carbon dioxide and sunlight into sugars and

water. This process only occurs when there is chlorophyll in the leaves (denoted by the green colour in leaves.)

Properties and Characteristics of Hardwoods and Softwoods

Softwoods HardwoodsCalled Pored wood. Called Non-Pored wood.

Simpler & more uniform cell structure. More random structure with large tube-like pores which vary in size.

Long, thin cells that are only visible under a microscope.

Short, stubby cells which can be visible to the naked-eye.

Come from the coniferous (having cones) or pine families of tree.

Include: Eucalypts, blackwood, maple, oak, walnut, ash, beech, willow, cedar, mahogany and hickory.

TIMBER CHARACTERISTICS

Figure Figure is the overall pattern of the wood along the grain and is dependent to variations, grain and colour.

Grain Grain refers to the direction of the fibres in relation to the axis of the tree and can be described as: Cross, spiral, wavy, etc.

Texture Texture is dependent on the arrangement and size of cells and can be described as: Fine, medium, course, uniform or uneven.

Colour Colour refers to the shades and hue of a section of timber. The colour of a section of timber will often change with the figure, grain and defects.

Strength Strength is directly related to the type of cell structure, cell size, wall thicknesses, lignin and direction of growth.

Durability Durability is largely reliant on moisture content and the presence of chemicals that are resistant to fungi and insect attack.

Sapwood generally contains more moisture, food and minerals and is therefore less durable than heartwood.

A timber does not need to be hard or tough to be durable.

Density Density of timber generally reflects how hard or soft a timber is as well as indicating its weight. This is measured in kg/m³ at 12% moisture content.

Hardness Hardness and softness are closely related to density through cell thickness and content.

Weathering Weathering is the breakdown of the exposed surfaces of a piece of timber due to action of sunlight, rain, wind, dew, frost and fumes.

Timber Conversion & Selection

When trees are first harvested the timber is classified as being ‘Green’ which means it still contains a large amount of moisture, gums and resins.

Seasoning is the process of removing the moisture content form the cells and cell walls inside the timber. Seasoning has a number of purposes: Reduce shrinkage, warping, weight, insect attacks and fungus. It also allows better adhesion and makes the timber easier to work with. The moisture content of some timber exceeds the weight of the wood itself, up to 200%.

There are two methods of seasoning timber: Air seasoning and Kiln Seasoning. Softwoods are suited to kiln drying and hardwoods are best seasoned by air drying first then being placed in a kiln, called combined seasoning.

Method Description Adv. / Disadv.Air This involves allowing harvested timbers to

sit still in a controlled environment (preferably in the workshop they will be used in). The key here is to stack the timber with consistent spacing and air circulation.

This method of seasoning uses less energy and therefore is more environmentally friendly.

The timber will naturally find its EMC.

This method can be slow and is dependent on the weather.

Kiln This involves drying the timber out in a large kiln oven which dehydrated the timber alot quicker than air drying. This must be controlled correctly. If it occurs too fast shrinkage and collapse may occur.

This method of seasoning has a higher degree of control and is alot faster than air drying.

This method requires special equipment and has a higher risk of over-drying the timber.

ECM (Equilibrium Moisture Content):o The ideal moisture content for the climate in which the timber will be used. o This is dependent on the local climate, humidity, temperature, etc.o In Sydney the EMC is 12% moisture content.

o Methods of Sawing Timber for Distribution

Once a tree has been cut down and transported to the saw mill it needs to be cut into sections for commercial use. There are a number of ways a log can be cut to produce sections with different characteristics. Each method has its advantages and disadvantages.

Method DescriptionLive Sawn Results in central planks being Quarter Sawn (with growth rings perpendicular to

the cuts) creating stable parts and outer planks being Back Sawn (with growth rings tangential to the cuts).

This is the most efficient and easier method of cutting as the log does not require rotation.

Back Sawn Back Sawing creates a series of cuts tangential to the growth rings. This is a highly flexible method of cutting that allows the log to be cut around faults such as hollow pith (seen in picture).

Quarter Sawn Quarter Sawing a log produces the most stable boards with the growth rings running perpendicular to the cuts. This is the least efficient method of cutting and creates a decent amount of wastage.

o Timber Industry Terminology Relating to Grades and Sizes

Timber Sizing Categories

Log A trunk with branches removed.

Flitch Over 100mm thick and over 150mm wide.

Plank Over 40 – 100mm thick and over 150mm wide.

Board 10 – 40mm thick and over 75mm wide.

Scantling Up to 150 x 100mm.

Battens 20 – 40mm thick and 25 – 75mm wide.

Strip Under 20mm think and up to 75mm wide.

Standard Sizing of Manufactured Boards (See Next Page)

Full Sheet Standard Common Dimensions: 2440 x 1220

Standard Common Thicknesses:4,6,9,12,18.

Timber Selection Considerations

Plantation timbers What are plantation timbers?Plantation timbers are timbers which come from specially established growth plantations. These plantations aim to produce as much timber as is in demand therefore saving timbers from natural forests and woodlands being harvested unsustainably.

Why would you choose plantation timbers?Choosing plantation timbers is an ethical decision which is made by businesses. Using plantation timbers save many natural forests from being destroyed which displaces much wildlife and kills off entire ecosystems.

Disadvantage of plantation timbers? Typically plantation timbers are more expensive to harvest than old-growth timbers because the plantation is owned by an organisation and not government land. Old-Growth forests offer much larger trees which give greater economic value.

Exotic timbers What are exotic timbers?Timbers that are imported, versus those that are grown in the country where you live. Many times, exotic timbers represent rare, or slow growth timbers from different parts of the world. Some are also common timbers from various parts of the world that are exported.

Recycling / reusing timbers

Recycling & reusing timbers is an environmentally sustainable option for woodworking and the timber industry. This means that new timbers do not have to be harvested and demands drop reducing the negative impacts of harvesting. This approach doesn’t only reduce the use of materials but also reduces waste as old products are not thrown out.

Waste minimisation

Waste minimisation can be achieved in a number of ways. Some include:

- Method of conversion – Live sawing produces less waste than quarter sawing.

- Using waste timbers for production of other products including particle boards and garden woodchips.

Sustainability Sustainability to achieved by producing plantation timbers which are equal to the demand of industry. Therefore maintaining an equilibrium where natural forests are not required for harvesting.

Look at protected species

One of the many negative impacts of forestry has been the endangerment of certain species of trees. There are now a number of protected tree species which cannot be harvested to protect them from becoming extinct.

Timber Defects

Natural Defects

Knots Knots are the result of branches which grow out from the centre of a tree causing a disruption in the grain which can be brittle and hard to work cleanly with tools or machines.

Seasoning Defects

Checks & Splits

Caused by rapid rehydration during seasoning.

Warping A broad term used to describe distortion.

Warping can include the following defects:

- Bow- Crook- Cup- Twist

Shakes Shakes are the radial separation of timber along the growth rings which can be causes by rapid dehydration.

Fungi Defects

Dry Rot Exists in dry conditions and cannot survive in well-ventilated areas.

Wet Rot Commonly found in living trees as it requires moisture to survive.

Manufactured Boards

The development of manufactured boards stems from two primary needs:

The need to reconstitute ‘waste’ material from harvested trees.

When used for solid timber roughly 40% of a harvested log can be used to produce the materials, however from that same log if we were to produce composite materials (eg: Manufactured boards) we can then recover up to 90% of the material for use.

The need for large, stable boards and panels which can be easily mass produced.

Solid wood boards recovered from harvested trees are typically limited to around 240mm wide. This is because as the timber section gets wider the more likely it is that the board will begin to twist, cup or bow. Using manufactured boards we can produce much wider boards which will remain flat and square under the same conditions.

The following manufactured boards are common examples of what we produce and use today:

PLYWOODManufacture & PropertiesA manufactured timber panel manufactured using veneers.

Timber veneers are thin sheets of timber which are rotary peeled off a log. These thin sheets are layered ontop of each other with alternating grain direction. Between each sheet an adhesive is applied which bonds the sheets together. Once the final stack of sheets is to the desired thickness pressure is applied which presses the sheets together and together with the adhesive, creates one solid board.

Plywood is one of the most widely used timber product on the market because of its versatility.

Plywood comes in a number of grades which signify the quality of the timber veneers which make up the board.

Advantages Stable Available in large sizes Strong Inexpensive Machine Workable Re-usable Is usually manufactured locally Can be moulded into forms

Disadvantages Because it is not one solid piece of timber ply is hard to work with hand tools Thin outer ply’s can splinter when worked

Uses

Plywood has a huge range of uses including outdoor, indoor aviation and marine use including:

Construction Signs Furniture Formwork Flooring Scaffolding Cabinet making

Available Sizes

Images

PARTICLE BOARDManufacture & PropertiesParticle board are made from small chips or flakes of wood bonded together under pressure; softwoods are generally used, although a proportion of hardwoods may be included. Advantages

- Available in large sheet sizes and thicknesses- Has no grain direction and is, therefore, uniform in strength- Can be used for carcase construction without framing- Compared with solid wood it is stable. It retains its shape well- Because of its stablilty, it forms an excellent base for covering with veneer or plastic

laminates.

Disadvantages- OHS – Dust can be an irritant- Edges require special treatment due to porous structure- Is more absorbent than most timbers and can swell up if left in a wet patch.- Tends to blunt cutting edges quickly- especially saw blades- Due to its flaky structure, is liable to break away on corners, care is necessary when screwing

or nailing near edges.

Uses- Often used as a base or core for veneers and plastic laminates.- Furniture industry uses it for carcases, tops, drawer parts and shelves.- Shop fittings- Shelving- Built-in furniture- Partitions- Feature walls- flooring

Available SizesAvailable in sizes up to 4880 x 1830 mm and thickness from 4 to 33 mm.Images

MDFManufacture & PropertiesAn engineered wood product formed by breaking down hardwood or softwood residuals into wood fibres, combining it with wax and a resin binder, and forming panels by applying high temperature and pressure. MDF is denser than plywood.

MDF has been banned from schools as working the boards can create a dust which has been categorised as carcinogenic.

Advantages Compared with solid wood, it is stable (subject to a little expansion and contraction); it

retains shape well. Has no grain direction; therfore it has unifom strength Can be used for carcase construction without framing Its easy to cut, sand, rout or profile because of its uniform density and internal bond

strength. Is easily worked with hand or machine tools Forms an excellent base for covering with veneer or plastic laminates

Disadvantages Gives off fine dust sawdust when machining Liable to break away when nailing or screwing mnear edges Can split when nailing into the end grain Banned in school environments

UsesMDP is used in a range of applications including:

Base or core for veneers, plastic laminates or painted surfaces Carcases, tops, drawer parts, shelves, picture frames, plaques and trophies Moisture resistant MDF – toys, internal doors, kitchen cabinets, shop fittings, partitions,

wardrobes Patternmaking

Available SizesLarge sheet sizes 3660 x 2440mmThicknesses range from 3 to 30mmImages

SURFACE VENEERS & LAMINATES:

To improve the aesthetic and performance characteristics of manufactured boards they are often given surface coverings. These include:

o Timber Veneerso Plastic laminates

Such as melamine which is used in most cabinet and furniture making.

These coverings are applied at the point of manufacture using adhesives and heat.

CONSIDERATIONS WHEN WORKING WITH MANUFACTURED BOARDS:

Economic sheet layout / planningo When producing products using manufactured boards you need to consider how

you are going to lay out your components to minimize wastage. Tear-out

o Manufactured boards are unlike standard timber panels – they do not have a grain and therefore respond differently to machining.

o You must ensure you are using sharp cutters and typically avoid hand tools. Storage & handling

o As these boards do not have a grain direction or growth rings they will not warp or cup to the same degree as solid timber.

FLAT-PACKING & MODERN ECONOMICAL FURNITURE:

Flat packed furniture is furniture which is left disassembled and stacked together in a small box. These types of products are assembled by the customer rather than the manufacturer. IKEA is the most prominent example of a company that takes advantage of flat-packing.

Advantages of flat-packing furniture:o Takes up less storage space – So you can fit more inventory in storage facilities.o You can fit more units into transport – so you save money on transport costs.o You do not have to assemble the furniture – so you save money on employees &

time.o You can produce the units in a smaller facility as there is no need for an assembly

line. o You can produce furniture which can be easily knocked down and relocated. o The savings made by the manufacturer in the above areas can be passed on to the

customers.

Processes

o Processes

Prior to Production Planning, Preparation & Production

Process DescriptionPrior to Production Before a project can be produced there are a number of crucial

steps that must take place:(These will all occur for your MDP)

- Finding an Intention for the project- Designing- Researching- Sketching (See Appendix for Example)- Workshop Drawings (See Appendix for Example)- Material Selection- Process Selection- Cutting list (See Appendix for Example)- Materials list- Project Costing (See Appendix for Example)- Planning steps of construction- Sourcing Materials

Planning Planning out involves a number of steps and considerations, including:

Plotting parts on the timber- Placing parts onto the timber as to be most efficient and create the minimum amount of wastage.

Measuring and drawing- Using appropriate measuring and marking tools to ensure that all lines are square and true.-Checking all measurements twice.

Ensuring that you have considered the following:-You have left gaps between parts to accommodate the width of the saw blade.- You have left ‘tails’ on all parts which need to be thicknessed so that any resulting damage to the ends can be removed.

Preparation of Timber The preparation of timber is crucial in ensuring that your materials are square, true and of the correct dimensions before you begin to work with them.DressingThicknessing Face Edge

Construction Techniques RippingCross-CuttingDrillingEdge TreatmentNailing & ScrewingSandingScrapingPlaning Chiselling

Other Construction Techniques

TurningCarvingMarquetryParquetryLaminatingBendingRouting

Joints

When selecting joints for woodworking you need to do your research and find which joint is most appropriate for the project you are doing. You should ask yourself a number of questions which will help you find the right joint for the job:

- What is the function of the product?- Is the joint under load / stress?- Is the product for indoors or outdoors?- Will the joint be seen or hidden?- What tools, fasteners or adhesives do I have available to produce the joint?

Widening JointsWidening joints are used for creating boards wider than those available.

JOINT WHY WOULD YOU CHOOSE THIS JOINT EXAMPLEButt It is easy to produce and requires not addition hardware,

only adhesive.This type of joint has no support and is therefore weak.

Dowelled Butt

The same as a butt joint but using holes and dowel to make the parts interlock and add support. This type of joint is stronger than a butt joint.

Tongue & Groove

Use mainly for flooring this joint has each piece interlocking through its side profiles to create a large surface area for gluing. This joint is strong and creates good stability.

Rebate A rebate joint in widening allows the edge of each piece to sit on top of the next creating good support. This joint is also easy to produce.

Groove & Feather

This joint uses a groove on either edge of meeting parts and a separate ‘feather’ which slides into the grooves to locate them together. The feather travels the entire length of the joint to create support.

Biscuit Similar to the feather joint a biscuiting machine half oval shaped grooves into parts which then use compressed fibre ‘biscuits’ to locate the parts together with glue. The biscuit absorbs the glue and swells, filling the grooves and creating good strength.

Domino Similar to the biscuit joint these dominos are slightly longer and penetrate deeper into each part to provide even more support.

Framing Joints

Framing joints are used for creating frames and structures.

JOINT WHY WOULD YOU CHOOSE THIS JOINT EXAMPLEMitre This joint is generally chosen as a means of hiding the

end grain of timber when creating a frame. A biscuit, dowel, domino or feather can be added for strength.

Halving The large surface area of this joint allows for more glue to be used on the joint as well as allowing an opportunity for a fastener to be fitted.

Dowelled This joint uses holes and dowel to make the parts interlock and add support. This type of joint is stronger than a butt joint and ensures that both parts locate correctly onto eachother.

Mortis & Tenon

This joint has one section of timber penetrate the other creating a great deal of surface contact area and support. This is a very stable and strong framing joint.

The tenon is typically 1/3 of the thickness of the timber uses for it.

Bridle This joint works in a similar way to the mortise and tenon however it lacks the upper support as the top of the joint is open. This is a strong joint selection for creating T joints for supporting beams.

Domino Similar to the biscuit joint these dominos are slightly longer and penetrate deeper into each part to provide even more support.

Carcase Joints

Carcase joints are used for creating enclosed objects. Eg: Jewellery boxes and Draws.

JOINT WHY WOULD YOU CHOOSE THIS JOINT EXAMPLERebate This joint uses the vertical walls of the carcase to

support the top panel which has a rebate ‘step’ cut from the ends to locate and fit to the side walls.

Rebate joints can be either through or stopped. Stopped rebate joints have a ‘step’ which stops before the front face of the joint.

Dovetail Dovetail joints and possibly the strongest joint you can use. The tails and slots cut in corresponding pieces interlock to create a rigid and stable joint. These are also chosen for their aesthetic appeal.

Housing Similar to the rebate joint the housing joint uses the side walls of a carcase to support the lateral sections. Housing joints are commonly used for shelving and can be produced in through and stopped variations.

Finger Similar to the dovetail these ‘fingers’ slot together to create a strong stable joint. They are not as strong as a dovetail as their do not lock together however they are easier to produce.

Tools & Machinery

MACHINE / TOOLS

DESCRIPTION / APPLICATION / MAINTENANCE

EXAMPLE OH&S

Cordless Drill Use for drilling holes in timber. This device uses a chuck with interchangeable drill bits for different sized holes.

The trigger on this tool is a variable speed trigger meaning it is pressure sensitive and has two speeds.

Apron, enclosed leather shoes, eye protection

Impact Driver Fastening and removing screws into or from timber.

This tool uses a spring collet which holds the driver bit onto the tool.


Jig Saw Cutting curved lines into manufactured sheets and boards.

This tool has a soleplate which rests on the workpiece and a reciporicating blade which cuts through the work.


Orbital Sander Sanding timber to get rid of excess material and to achieve a smooth surface finish.


Hand Router Routing joints, trenches and end treatments on timber.

This tool uses a chuck with a collet which holds the cutter into place.

Apron, enclosed leather shoes, eye protection, ear protection.

Band Saw Making small cuts or cuts which include curved sections.

This machine uses a belt-type blade which runs around a 3-pulley motor driven system.


Table Saw Cutting timber to the correct length and width as well as cutting grooves into sections of timber.

This is primarily used for cutting manufactured boards.


Drop Saw Docking timber to lengths or cutting angles on the end of timber sections.


Radial Arm Saw Docking timber to lengths or cutting angles on the end of timber sections.


Linisher Sanding along the grain of timber sections to remove excess material and achieve a smooth surface finish.

Apron, enclosed leather shoes, eye protection.

Disc Sander Sanding end-grain on timber sections.


Spindle Sander Sanding in tight concave surfaces or internal surfaces to remove excess material and achieve a smooth surface finish.


Drill Press Drilling into or through sections of timber perpendicular to the surface.

This machine uses a chuck with a key to tighten and hold drill bits inside the chuck.


Mortise Machine

Removing material from a section of timber to create a mortise hole for a mortise and tenon joint.


Air Compressor Used in conjunction with an air gun to remove sawdust from projects or used in conjunction with a spray gun to apply a finish to projects.


Spray Gun Filled with a range of finishing materials this attachment allows the user to spray even coats of finish to a surface.

Apron, enclosed leather shoes, eye protection, respirator mask.

Dovetail Jig This jig is used in conjunction with a router to produce a repeated pattern.

Jigs are used in industry to

only for cutting but also for drilling.

The idea behind a jig is that if you use the same jig on every product they would turn out identical. This is important when accuracy and quality control are crucial.

Chisels While chisels are not used regularly in industry they are still used for certain jobs and are still a common tools for craftsmen.

Chisels can produce joints, remove excess material, create surface detail and clean up edges of timber.

Chisels are honed at a certain angle depending on their purpose.

Fore paring chisels should be honed at 25 degrees and for chopping: 30 degrees.

Adhesives

Glue Type Description Use / ApplicationPVA (Polyvinyl Acetate)

Also known as carpenters glue this is a good general purpose glue for woodworking which is easy to clean and dries clear. It is moderately strong but not suitable for use outdoors as it not water resistant.

General woodworking Indoor use only

Drying time: 24 hours – 1 week.

Contact adhesive Not suitable for bonding sections of timber together. Adhesive is applied to two surfaces, wait 10 minutes and press together for an immediate bond.

Applying laminates to timber surfaces.

Drying time: Instant adhesion.

Epoxy Resin Very strong and waterproof this is a 2-part adhesive. A glue and a hardener are mixed and the chemical reaction causes them to set. It can bond all types of material together.

Indoor & Outdoor use. Suitable for strong

joints.

Drying time: 24 hours – 2 days.

Hot-Melt Adhesives

Applied through a hot-glue gun these adhesives are quick to set and offer a somewhat strong but often temporary bond for timbers and other materials.

Non-structural joining Attaching temporary

panels.

Drying time: 30 minutes – 1 hour.

Polyurethane Glue

Claimed to be the toughest glue ever this offers excellent hold, water resistance, ease of application and allows various materials to be bonded in a short amount of time.

Must be applied to a damp surface as it reacts with the moisture to set.

Adhering materials of different natures together (Eg: Timber and Plastic)

Drying time: 24 hours - 3 days.

Formaldehyde Glue(Urea Formaldehyde)

This is the most commonly used adhesive in industrial situations. It comes in both powder and liquid and is cured with an additive of wood flour.

This glue is used in the manufacture of marine-grade plywood as it is waterproof and heat resistant.

Use primarily in the production of manufactured boards this is applied in liquid or sheet form before heat and pressure are applied.

Drying time: 30mines – 12 hours.Animal Glue One of the oldest glues known to humans

this has been superseded by PVA. It has to be heated to be used and can be unset with heat. These glues are non-water resistant but can be very strong in dry climates.

Used in modern times by antiques craftsmen and restorers.

Drying time: Approx. 15 minutes.

Finishing

Reasons for applying a finish to timber products include:

Aesthetic appealo Improve the overall visual appeal of the project. Finishes can enhance the look of

different timbers and forms. Preservation of the timber

o If the project has a protective layer of finish covering it there is no longer a risk of the elements degrading the timber.

Prevent insect or fungi attacko Insects and fungi are less likely to be able to penetrate the timber finish.

Protect the surface of the timbero High-use surfaces on furniture pieces can suffer from wear. Eg: coffee cups being

pushed on the surface or liquid spilling onto the timber. A finish will create a barrier to protect the timber from these things.

Improve the performance of the timbero Perhaps the timber needs to allow something to slide along it. Therefore you might

apply a surface finish such as wax to allow this performance.

Process of Preparing timber for finishing:

Raise the graino Dampen the surface of your timber with a moist rag which will cause all loose timber

fibres to raise up. Leave to dry.

Sandingo Using a variety of sandpaper grades sand down the timber surface with the raised

fibres until it is smooth.

Repeato Once the timber surface is smooth again re-raise the grain and sand again with a

finer grade of sandpaper.

Smoothingo If the surface needs to be perfectly smooth you might consider using a scraper on

the surface of your project. This tool is like a metal squeegy which scrapes the timber surface smooth, leaving a clean, flat face.

TYPES OF FINISHES:

Water-Based Finishes: Water-based paints and finishes are cheap, safe, dry quickly, are easily applied and environmentally friendly. An example is the ‘Estapol’ we used at school.

Turpentine-Based Finishes: Turpentine-based stains offer the best protection for a timber project however they are slow-drying which allows for dust and debris to settle on the project during this period. The best know type is Polyurethane finish.

Spirit-Based Finishes: Spirit-Based finishes can produce the most impressive gloss finishes but are not suitable for high-use surfaces because they can be effected by heat and marking. Examples include French Polish and Shellac. These have been largely replaced by synthetic lacquers which can now deliver a similar finish.

Oil Finishes: Oil finishes can be easily wiped on and seep into the fibres of timber. Examples include: Linseed oil & Orange Oil.

Waxes: Waxes such as bee’s wax can be applied dry or melted and applied before being buffed hard and fast to produce a gloss finish.

METHODS OF APPLYING FINISHES:

Applying a finish is a process which should not be rushed. By taking your time and ensuring consistency you can achieve a clean, glossy finish on any peice of work.

Generally speaking the more coats you apply to a piece of work the higher the quality of finish will be. However exceeding 3-4 coats is likely to be excessive.

Between coats it’s important that you give the previous coat a very light sand with a fine grade sandpaper or steel-wool and wipe the piece clean from dust again before applying the next coat.

METHOD APPLICATION / PRODUCT IMAGESPRAYING Applying a finish with an air-gun is an industrial

method which can be used by individuals, however special equipment, PPE and adequate ventilation are required.

The reason for this is that it is a fast and effect way of acheiving consistant coats accross a large area in a short ammount of time.

BRUSHING Applying a finish with a brush is a clean, safe and accurate method for applying a finish. This method is used in shools as it doesn’t always require special PPE and can be acheived using just a basic brush. Craftsmen often choose to brush on finishes, especially on small items because of its accuracy and higher level of control.

The downside to this method is that it is slow, inconsistent over a large area and can create runs in the finish.

WIPING Certail types of finishes such as oils create a better finish when they are wiped on rather than sprayed as this helps them penetrate the grain more effectively.

Wiping on a finish can be done easily with a lint-free cloth. This is another method which suits large, flat surfaces.

RUBBING Similar to wiping, some finishes such as waxes need to be rubbed into a workpiece to achieve a desired finish. Rubbing a finish in can be hard work but gives the craftsman good control as to the level of the finish. Waxes often require heating before being applied.

STAINING TIMBER

Timber finishes come in a number of solvents including: Oil-based, Water-based and spirit-based. When handling any type of stains safety precautions should be taken including the use of respiratory protection in the form of a mask and the use of gloves to protect the hands. All staining should also take place in a well-ventilated area.

To acheive the best results when applying stains to a project they should be brushed on or wiped onto a workpiece. Methods such a spraying do not work as well for stains as the liquid needs to penetrate the surface of the timber rather than sit ontop of the surface.

Reasons for staining timber:

Change the colour for aesthetic appealo Certain colours on timber are more desirable than others, stains can change the

colour of the timber to a more desirable tone. Make a cheap timber looks like a more expensive timber

o Certain cheap timbers like pine which have a light colouring can be stains to appear darker and therefore look more expensive.

When timber varies in tones a stain and even out all the surfaceso Some timbers have a grain that will change colour and tone throughout the surface,

staining is one way to make the whole surface one consistant tone. To match a piece of furniture to other pieces in its surroundings

o Often staining is necessary to make a piece of furniture match other pieces in a room. Staining might be an easier option than finding timbers that match up.

Hardware and Fittings

Hardwareo Screws

Parts Head, Shank, Thread.

Common Materials

Generally Mild-Steel [Available in stainless]

Common Coatings

Zinc plated, Copper plated and Galvanised.

OrderingInformation

Head type, length, material, coating and quantity.

o Nails

Parts Head, Shank, Tip.Common Materials Mild Steel, Stainless Steel, Copper, Bronze.Common Coatings Galvanised, nickelled and brassed.Ordering Information Head Type, Length, Diameter, Material, Coating, Quantity.

o Nuts & Bolts

Parts Nuts: Head, Thread. Bolts: Head, Shank, Thread.

Common Materials Mild Steel, Stainless Steel.Common Coatings Galvanised, nickelled and brassed.Ordering Information Head Type, Length, Diameter, Material, Coating, Quantity.

o Knockdown Fittings

Type Use / Application ExampleBolt and Cross Dowel Normally used on beds, tables

and chairs.

Tee Nut and Screw When tightened for the first time the nut bites into the wood and stays captive.

Cam Fitting Used in desk assemblies, only requires a quarter turn to lock tight.

Cabinet Connector Often used to link kitchen cabinets and still looks good inside.

Block Connector Used for low-stress connections with less movement, not seen from the outside.

Screw Connector Course thread for particleboard use, supplements other fittings like supporting the centre of a shelf.

Particle Board Insert Inserted in particleboard allowing wood screws to be used, expand and grip the drilled holes.

o Hinges

Hinge Type Use / Application ExampleButt Cabinet-making, doors up to room door size.

Some have a removable pivot hinge.

Piano Strip Hinge (2m) for continuous support. It is cut to length and surface mounted.

Flush Light-weight use, surface mounted and easy to fit.

Lift Off Butt For situations requiring easy removal. Pin is removable.

Rising Butt For room doors. Has three benefit: lift off, rises as opened to clear carpet and a self-closing tendancy.

Concealed Cabinet For use in MDF and particle board cabinets.

Back Flap For bureau drop flaps and table ends.

Parliament Knuckle sticks out to allow external and room doors to fully open to 180 degrees.

Furniture Components & Assembly

Legs Legs are the members which hole a furniture piece off the ground.

Legs can be produced in a number of ways which will depend on the aesthetic of the design.

Legs can be cut from flat timber sections or turned to produce a round profile on a lathe.

Legs are commonly found on chairs and tables and are connected to rails.

Common methods of connecting a leg to a rail include:

- Mortise & Tenon- Domino Joint

Rails Rails are the members which run between the legs and usually support the top of a table or the seat of a chair.

Rails are typically long rectangular sections and often have areas cut out to fit drawers.

Rails are commonly found on tables and chairs. They are the members which joined to the legs together and attach to the top or seat.Common methods for connecting a rail to a top or seat include:

- Fastening Blocks- Metal brackets- Locating Dowels

Top & Base Tops & bases can be found on any

number of furniture pieces.

These are typically wide, flat boards which sit on top of a table or in the case of an enclosed furniture piece such as an entertainment unit the top and base are found on the upper and lower surfaces of the piece.

On a carcass the tops and bases are typically joined to the side panels of the carcass with the following joints:

- Rebate Joint- Domino Joint- Mitre Joint- Butt Joint

Side Panels These are typically flat panels which support the weight of the top and rest on the base.

These panels often also support shelves on their inside face.

On a carcass the side panels are typically jointed to the shelves using the following joints:

- Through Housing- Stopped Housing

Shelves Dividers

These are held in place inside the carcass of a piece and often create cavities for drawers to sit inside.

Dividers are typically connected to drawers by runners, rails or simply locate inside.

Doors Doors cover the openings on a carcass and offer enclosure as well as access.

Doors are typically connected to the carcass (usually side panels or dividers) using:

- Hinges- Runners

Fitting & Assembly

Once all joints have been cut and prepared the next stage is to fit and assemble the project. This process involved double and triple checking for squareness and flatness before final assembly is completed.

Process:

CHECK JOINTSo All joints should be checked visually to ensure they have been cut cleanly and

there are no obstructions or missed areas.

TEST THE JOINTS o Hold the two joints together by hand to check for accuracy and visual fit.

DRY ASSEMBLE o Assemble the project ‘dry’ (without adhesives or fasteners) to check for all

round fit.o Visually inspect each joint and ensure that they are sitting correctly. o During this stage use a tri-square and ruler to check for squareness in all

areas of the workpiece.

DISASSEMBLEo If the joints are all up to standard you should then disassemble the project.

APPLY ADHESIVESo Apply all glues where appropriate and assemble the job again.

CRAMP THE WORKPIECE GENTLEo Using the appropriate cramps lightly cramp the project and allow all joint to

position correctly.

CHECK FOR SQUAREo Re-check all joints to ensure they are sitting where they should be and that all

surfaces are sitting flat.

TIGHTEN CRAMPSo Slowly and evenly tighten the cramps in a logical order until all cramps are

tightened to the appropriate level.

FINAL CHECK FOR SQUAREo Check all the aspects of the project again to ensure they are sitting flat and

square.o Methodically loosen and tighten cramps until the workpiece sits correctly.

POST-PRODUCTION DOCUMENTATION

CUTTING LISTS:

A cutting list is created by looking at a set of drawings of a project and extracting all the necessary information to cut the individual parts out to exact sizes.

Here is an example of a complete cutting list for a basic coffee table design:

Part Name Qty. Length Width Thickness MaterialA Slab Top 1 1500 800 30 Silky OakB Leg 4 500 80 80 Sydney Blue GumC Frame (Front & Back) 2 1340 80 40 Sydney Blue GumD Frame (Sides) 2 640 80 40 Sydney Blue GumE Fastening Blocks 8 100 40 40 Sydney Blue Gum

COSTINGS SHEET:

A costing sheet is produced based on a cutting list to calculate the cost of a timber order.

Material Cross-Section Size

Cost per linear metre

Cost x Length Sub-total

Pacific Maple 150x25 $5.46 $5.46 x 11.4m $62.24Radiata Pine 50x50 $2.12 $2.12 x 0.9m $1.91

SUBTOTAL: $64.15GST @ 10%: 6.42

TOTAL: $70.57

WORKSHOP DRAWING:

A workshop or working drawing should be produced for every project to ensure that all parts of the project have been accounted for. These drawings should include all essential dimensions for producing the item.

INDUSTRIAL PROCESSES AND MANUFACTURING:

COMPUTER AIDED DESIGN (C.A.D) & COMPUTER AIDED MANUFACTURING (C.A.M)

C.A.D Computer Aided Design is the process of using computer software to build and develop three dimensional models. These models allow for accurate dimensioning, easy alteration to design, clear presentation and can be used to produce excellent workshop drawings.

C.A.M Computer Aided Manufacturing uses the information from CAD models and other software to produce parts of projects using machines such as computer controlled routers, laser cutters, etc.

Industrial manufacturing processes

Jigs A jig is a device which is used to hold a workpiece while a repeated operation is performed on the piece.

Common jigs include:- Dovetail Jig- Finger joint Jigs

Cutting templates Cutting templates are an object which is used to produce a repeated pattern across a number of work pieces.

This might include a lasercut panel which shows you where to drill or which can be used with a trimmer to cut multiple boards into the identical shape.

- Drilling Templates- Routing templates- Lathe turning templates

CNC routers & cutters Computer Numerically Controlled machines are industrial machines which are operated by a C.A.M. program rather than an operator. These are used for repeated accuracy, fast production time and hard to produce forms.

For a good example of industrial furniture manufacturing search for the following video on YouTube: ‘How Its Made – Chipboard Desks’

OH&S

Occupational Health and Safety covers almost every aspect of industrial technology. In simple terms OH&S all things related to the health and safety of individuals in the workplace (the workshop for you). OH&S is an essential component of any workplace and project.

ELEMENT DESCRIPTION / SUMMARYLegislation The OH&S act of 2001 is a legislative document which ensures the health,

safety and welfare of all persons at work. The act requires employers to consult with workers on matters effecting their health, safety and welfare. This is generally done through OH&S committees or representitives as a means of resolving any associated problems.

Work-Cover This is the NSW body responsible for managing the state’s workplace safety, injury management and worker’s compensation programs. WorkCover enforces the OH&S regulations through education, inspections, investigations into incidences and where necessary applies penalties and fines.

Risk Assessment Risk assessment is a very important part of maintaining a safe working environment. All tools and machines require a risk assessment to determine possible danger and hazards involved in using the item.

Risk Management Once a tool or machine has been assessed controls can be put into place to reduce the risks involved in operation. These are broken up into two main catagories:

Engineered Controls:These include physical objects which can protect the user from hazards including guards on machines and PPE.

Process Controls:These include steps of operation and procedure which are designed to keep a user safe including safety zones, material safety data sheets (MSDS) and safe operating process sheets mounted next to machines.

First Aid First aid is an essential skill set to have in any workplace. This involves attending to a patient for an injury as soon as it happens while waiting for further assistance such as an ambulance if it is required.

Personal Protective Equipment (PPE)

Many potential hazards can be controlled through the use of PPE. Examples of PPE include:

- Eye Protection: Goggles- Hearing Protection: Ear Muffs- Body Protection: Apron- Head Protection: Face Shield- Skin Protection: Gloves- Respiratory Protection: Masks and Filters- Foot Protection: Leather Shoes

DRAWING & COMMUNICATION

What is the purpose of a sketch?

• Quickly communicate an idea

• Quickly and easily show details of an idea

• Easily visualise an idea from your thoughts

What are the rules of sketching?

• Always use annotations to help communicate ideas

• As long as the sketch clearly communicates the idea to the client it has achieved its purpose

What is the purpose of a model?• To materialise an idea from a set of drawings.• To check the proportions of a design at a small, quick and easy to produce scale.

What is the purpose of exploded drawings?• To show how elements of a project come together and show details of joints, fasteners, etc.

What are the rules of dimensioning?Generally exploded views are draw in isometric view and spread the components out enough that you can see all the necessary details.

What is the purpose of working drawings?• To communicate all views, dimensions and details of a project.

What are the rules of dimensioning?1)Must have all essential dimensions 2)Must be clear 3)Avoid repeating dimensions 4)Use a pencil 5)Dimensions in full size 6)All text must be upright

Example of a working drawing.

An example of a page of sketches with annotations. Your sketches should have more annotations than this. It should be a conversation with your drawings!

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