Lesson video

Hello, I'm Mrs. Taylor, and I'm really pleased you can be here to join me for our lesson today.

Our lesson today is sources and stock forms of timber, and this is part of the technical principles unit.

The outcome.

I can describe where different materials come from and identify their stock common forms. There are four key words, source, which is where a material originates from.

Raw material, a natural material in its original state.

Process, changing a material to make it suitable for making products.

And stock form, the standard shape or size a material is supplied in.

There are two parts to our lesson today, sourcing and processing materials and material stock forms. Let's begin with sourcing and processing materials.

A source is where a material originally comes from.

For timber, the source is trees, which are a natural and renewable resource.

There are two main types of trees used for timber.

Hardwoods, for example, oak.

They are slow growing and have broad deciduous leaves.

And softwood trees, for example, pine, they are faster growing, they have needle-like evergreen leaves.

Timbers can also be man-made, manufactured boards.

These are made in a factory, often combining natural timbers with synthetic resins.

Plywood is made with thin sheets of natural wood and adhesive that are in alternate layers.

Chipboard is made from wood chips that have been mixed with resin and compacted.

And MDF, Medium Density Fiberboard is made from wood fibres that have been compacted with resin.

We now have a check for understanding which of the following is a source of timber.

Is it A, a sawmill.

B, the ground.

C, a tree.

Or D, a timber merchant.

Pause the video and have a go.

Fantastic.

Let's check.

That's right, it's C, a tree.

Well done.

Timber is a renewable resource.

This means it can regrow naturally and be replaced over time through responsible forestry practises.

This means it can regrow naturally and be replaced over time through responsible forestry practises.

For example, the Forest Stewardship Council is an organisation that promotes responsible management of the world's forests.

Products that are sourced from responsibly managed forests carry the FSC logo.

Here we can see an example of the FSC logo.

Sustainable means that the resource can replenish itself so future generations can meet their needs.

Through carefully managed forests, for example, replanting failed trees, timber is a sustainable material.

However, through unlawful practises such as illegal logging, timber use can become unsustainable.

Deforestation can be damaging to the environment.

Here we have a check for understanding.

Which of the following best describes sustainable timber? Is it A, timber harvested from forests that are managed carefully? B, timber that is cut down as quickly as possible to meet demand.

C, timber that is imported from another country.

Or D timber that is only used for making furniture and not construction.

Pause the video and have a go.

Great, let's check.

That's right, it's A, timber harvested from forests that are managed carefully.

Well done.

Different types of timber grow in various climates and regions.

Coniferous softwoods are most common in Northernmost Europe and Northwest America.

Tropical hardwoods mainly grow along the equator.

Some hardwoods grow in more temperate climates as well as some softwood species.

Transporting timber from far locations can contribute to carbon emissions.

Softwoods and hardwoods differ in the time it takes for them to reach maturity, i.

e.

when it's can be cut down.

Hardwood trees like oak take about 80 to 120 years to reach maturity.

Softwood trees like pine take about 20 to 30 years to reach maturity.

Softwoods are more widely used for construction and manufactured boards due to their faster growth rate.

This also makes them cheaper than hardwoods.

Whilst bamboo comes under the category of timbers, it is actually a type of grass.

Bamboo is a popular alternative raw material because of the rate at which it grows, making it a sustainable choice.

Bamboo can take approximately five years to reach maturity and can regenerate faster than trees.

Bamboo shares many properties with wood from trees and grows quickly, making it an ideal material for disposable cutlery.

Here we have a check for understanding.

Sort the following timbers into hardwoods and softwoods, mahogany, pine, oak, ash, beech, cedar, balsa, and spruce.

Pause the video and have a go.

Fantastic.

Let's check.

The hardwoods are mahogany, oak, ash, balsa, and beech.

And the softwoods, pine, cedar and spruce.

Well done.

A raw material is a natural material in its original state.

Timber is a raw material sourced from trees.

It needs to go through three main stages before it can become usable/ Felling, which means to cut down.

Conversion and seasoning.

Felling is the term used to describe the cutting down of trees, which are the source of timber.

This can be done manually with chainsaws by trained workers.

It can also be done mechanically using large machinery.

Once the trees have been cut down, their branches and bark are stripped creating logs.

Chainsaws can be used to fell trees.

The felled logs are still a raw material and need to be processed into a usable form.

This is called conversion.

Through and through sawn timber make straight cuts across the log.

This is a quick process, however, the plank are more likely to distort.

Quarter sawn timber is sectioned more effectively so that there is less waste and distortion.

However, this process is more expensive.

Here we have a check for understanding.

What is the main purpose of timber conversion? Is it A, to dry the timber to reduce moisture content.

B, to cut down trees in a managed way.

C, to treat timber with chemicals to prevent decay.

Or D, to cut logs into usable sizes like planks or beams. Pause a video and have a go.

Wonderful.

Let's check.

That's right, it's D, to cut logs into usable sizes like planks or beams. Well done.

Seasoning is the final step in processing timber from a raw material into a usable form.

Felled trees have a moisture content of around 60%.

Seasoning reduces this moisture and makes the timber more stable.

Benefits of seasoning timber are, prevents distortion reduces splitting, minimises shrinkage, easier to machine and increases strength.

Bowing, cupping and twisting are examples of how timber can become distorted if they retain too much moisture.

Timber can be seasoned in one of two ways.

Air seasoning is a traditional and natural method to dry timber.

The timber is stacked outside undercover with spaces to allow airflow.

Depending on the climate, this process can take several months to complete.

However, this is a cheaper and more environmentally friendly method as it doesn't use energy.

The planks are raised off the ground and stacked between spaces for airflow.

Kiln seasoning involves drying timber in a heated chamber where the temperature and humidity are closely monitored.

Fans keep the air circulating between spaced timber stacks to speed of the process, which takes a few weeks.

The disadvantages of kiln seasoning are energy consumption and cost.

The hot air circulates in a kiln to season timber planks.

Here we have a check for understanding.

Why is timber seasoned before use? Is it A, to improve the appearance of the timber? B, to reduce the moisture content and prevent warping or decay.

C, to remove pests and insects from the timber.

Or D, to make the wood easier to cut into planks.

Pause a video and have a go.

Wonderful.

Let's check.

That's right, it's B, to reduce the moisture content and prevent warping or decay.

Well done.

We now move to task A.

There are three parts.

Part one, explain the difference between a raw material and a processed material using timber as an example.

Part two, use diagrams to explain two methods of converting timber into a usable form.

Give an advantage and disadvantage for each.

And part three, explain why timber needs to be seasoned and describe two methods of doing so.

Give an advantage and disadvantage for each method.

Pause the video and have a go.

Wonderful, let's have a look at some of the answers you may have come up with.

For part one, you may have said, a raw material is a natural material in its original state, timber in the form of a felled tree is a raw material.

When it is cut, seasoned and shaped into planks, it becomes a process material suitable for use in products.

For part two, you may have drawn diagrams that look similar to this and you may have said, through and through sawing cuts the log straight through from one side to the other.

It is quick and produces little waste.

However, the boards are more likely to distort as they dry.

Quarter sawing sections the timber into quarters and then each quarter is sawn at an angle.

It produces more stable timber, but this is time consuming and produces more waste.

And for part three, you may have said, timber needs to be seasoned to reduce its moisture content, which makes it more stable and less likely to warp over time.

One method of seasoning is air seasoning where timber is stacked undercover outdoors between spaces so the air can gradually remove the moisture.

This method is environmentally friendly and inexpensive, but it takes a long time and relies on suitable weather conditions.

Another method is kiln seasoning where timber is placed in a controlled, heated chamber that speeds up the drying process.

This method is much faster, but it is more expensive and uses energy.

Well done.

We now move to the second part of our lesson today.

Material stock forms. A stock form is a standard shape and size in which material is supplied.

Standardising means the shape and size of the material are made to specific dimensions.

Stock forms allow designers and manufacturers to know which form a material is available in.

This information is required when designing a product and planning its manufacture.

Timber that goes through the conversion process at a sawmill is referred to as rough sawn timber.

This is normally used in construction as aesthetic appearance isn't important.

The timber can go through a secondary conversion process where it is planed smooth or cut with a spindle moulder to create decorative lengths.

Timber can be plain smooth for uses that require aesthetics.

For example, furniture.

For timber process stock forms are as follows.

A plank is thick, wide and long used for flooring.

A board is thin, wide and long used for panelling.

A sheet, manmade boards in different thicknesses.

A strip is narrow, thin and long used for framing.

PAR, which means plain all round or PSE, means plain square edge.

These are smooth on all sides ideal for furniture, Dowel is cylindrical shaped in a range of diameters.

And moulding, decorative lengths used as skirting board.

Here we have a check for understanding.

What does standardised mean? Is it A, made in different shapes and sizes every time? B, made the same way every time so it fits and works well.

C, made only by hand.

Or D, made to be thrown away after one use.

Pause the video and have a go.

Wonderful.

Let's check.

That's right, it's B, made the same way every time so it fits and works well.

Well done.

There are many benefits to materials being available in a range of stock forms. These include handling, easier to store and transport.

Cost, bulk production of standard sizes lowers costs.

Waste, buy only what is needed.

And efficiency, consistent sizes are easier to work with.

Most stock forms of timber come in the following standard sizes.

Widths and thicknesses.

For example, 20 by 100 millimetres.

Lengths, for example, 1.

8 metres, three metres or 4.

8 metres.

Sheets, for example, 1.

8 metres, 2.

4 metres or three metres.

Diameters, for example, eight millimetres diameter or 25 millimetres diameter.

However, widths and thicknesses can vary.

This is called the nominal size.

For example, a plank labelled as 25 millimetres by 100 millimetres.

Nominal may actually measure 22 millimetres and 94 millimetres actual.

This is because planing and smoothing removes a few millimetres from each surface.

We now have another check for understanding.

What is one main benefit of using materials in standard stock forms? Is it A, it ensures all products made from the material will have identical properties? Or B, it eliminates the need for quality control.

Or C, it makes material selection and processing more efficient and cost effective.

Or D, it allows for completely custom sizing.

Pause the video and have a go.

Wonderful.

Let's check.

That's right, it's C, it makes material selection and processing more efficient and cost effective.

Well done.

Sometimes you will need to work out how many pieces of a product can be cut from a length of timber.

Calculate the total cost based on length or volume used.

Estimate the waste leftover after cutting.

A piece of PSE timber is 2,400 millimetres long.

You need pieces that are 600 millimetres long.

How many full pieces can you cut? 2,400 divided by 600 equals four pieces.

If each 600 millimetre piece costs two pounds 50, what is the cost of four pieces? Four times two pounds 50 equals 10 pounds.

When calculating the amount of timber required, there may be occasions when you have to run down.

This is because any leftover timber called an offcut is too short and can't be used to make another full length.

For example, you are making garden steaks, each 550 millimetres long.

You have timber planks that are 2,400 millimetres long.

How many full garden steaks can you cut from one plank? Step one, 2,400 divided by 550 equals four pound 36.

Step two, round down to four full stakes.

The remaining 200 millimetres is an offcut, which is not long enough for another stake.

Rounding down still applies when calculating sheet materials.

For example, you have a standard plywood sheet of 2,440 millimetres by 1,220 millimetres.

You need rectangular panels measuring 800 millimetres by 600 millimetres.

How many full panels can you cut from one sheet? Step one, panels along the length, 2,440 millimetres.

2,440 divided by 800 equals 3.

05, which is three full panels with 40 millimetres left over.

Step two, panels along the width, 1,220 millimetres.

1,220 divided by 600 equals 2.

03.

This is two full panels with 20 millimetres left over.

Step three, total panels.

Three panels, the length times two panels for the width equals six full panels.

Here we have a check for understanding.

You are cutting 800 millimetre pieces from a 3,000 millimetre length.

How many full pieces can you cut? Is it A, three? B, 3.

75.

C, four.

Or D, two.

Pause the video and have a go.

Wonderful.

Let's check.

That's right, it's three, which is option A.

Divide, then check if there's enough for another piece.

So 3,000 divided by 800 equals 3.

75 where we ran down to three full pieces.

Well done.

Here we have task B.

There are three parts.

Part one, describe what a stock form is.

Give one example of a stock form and explain how it might be used in a product.

Part two, explain two reasons why timber and sheet materials are manufactured and sold in standard sizes.

And part three, you have a plywood sheet measuring 2,440 millimetres times 1,220 millimetres.

You need rectangular panels that are 750 millimetres by 500 millimetres for a project.

How many full panels can you cut from one sheet? Pause the video and have a go.

Wonderful.

Let's have a look at some of the answers you may have come up with.

For part one, you may have said, a stock form is a standard shape and size in which material is commonly supplied.

An example of a timber stock form is a moulding.

Mouldings are decorative and are often used for skirting boards and door frames.

Using stock forms makes it easier and faster to manufacture products.

And for part two, you may have said, standard sizes allow manufacturers and designers to plan products more efficiently because the dimensions are predictable.

This reduces time spent measuring or adjusting materials to non-standard lengths.

Using standard sizes helps reduce material waste because products and components can be designed to fit these dimensions leading to more efficient use of materials and lower production costs.

And for part three, step one, the panels across the length are 2,440 millimetres, which is divided by 750, which equals 3.

25 and we ran this down to three panels.

Step two is panels along the width, which is 1,220 millimetres divided by 600 equals 2.

03, rounded down to two panels.

And step three, the total panels are three panels from the length times two panels from the width equals six full panels.

Well done.

We now have a summary of our learning today.

Raw materials need to be sourced and processed into a usable form.

Materials are available in a range of stock forms, which influences material selection and production methods.

Rounding down is necessary for calculations because small offcuts can't be used as full pieces.

I'm really pleased you could be here to join me for the lesson today.

Thank you and well done.