Lesson video

Hello, thank you for joining me for your design and technology lesson.

My name is Mrs. Conway, and I will be guiding you through your learning today.

So today's lesson outcome is, I can finish the surface of a product to a high standard.

And these are our key words.

We have surface finishes, timber, sanding and wood grain.

We'll go through each one of these in a little bit more detail as we work through the lesson.

So the first thing we're going to look at then is the preparation of timber for surface finishes.

Now, surface finishes are coatings or treatments applied to a material or a product.

Before applying any surface finish to timber, however, the timber must be properly prepared.

Just to remind you of what timber is then, timber is wood cut from trees to use in manufacturing, and here are some examples of some timber planks.

Now it's important to prepare the timber to get a smooth surface as any imperfections on the surface will be very visible once a surface finish has been applied.

So for example, with some surface finishes, it is possible to see pencil and pen marks on the surface.

So you can see in the example in the picture, we've got some marking out pencil lines on the timber.

Now if we don't remove those or prepare that surface properly, we'll still be able to see them once the finish has been applied.

So it's really important that we remove those before we start applying the finish.

Now a clean smooth surface also helps the surface finish stick better and more evenly as well.

So without this preparation, surface finish may not adhere properly and could peel or flake over time.

Preparing the timber also improves the final appearance as well.

So sanding, for example, brings out the natural grain of the wood and creates a more professional-looking result.

So there's lots of reasons why we prepare the surface of the material before applying the finish.

Sanding is smoothing or shaping the surface by rubbing it with sandpaper or an abrasive paper.

And wood grain is the natural patterns of lines and textures in timber, and these are created by the arrangement of its growth rings and fibers.

So here's an example of an unfinished wood grain, and here's an example of a wood grain that has been sanded and varnished as well.

And you can see it actually almost like brings out the color and the pattern of that wood grain and can add a lot of aesthetic appeal to the product.

Now, one way to get a smooth surface is to use a smoothing plane.

A smoothing plane works best on natural timbers or on the edges of manufactured boards.

Here's an example of a smoothing plane being used, and it's being used in this picture to remove thin layers of timber.

Now a smoothing plane is used after rough shaping just to improve the surface.

It also removes any marks left by other tools by shaping off really thin layers.

Okay, quick check for understanding then on what we've just covered.

Which of these images shows a smoothing plane? Is it A, B, or C? Pause the video here.

Just take a moment to think about your answer.

And the correct answer, it was C.

Well done if you got that right.

As well as using a smoothing plane then, another process we could use is sanding.

And sanding smooths the surface of timber in preparation of the surface finish as well.

Sanding is done by rubbing the surface of the material with an abrasive material like abrasive paper, as shown in the picture there.

And you may have seen this in the workshop at school before or maybe even at home.

Abrasive paper is a hand tool used to smooth or clean surfaces.

And an effective way to use abrasive paper is to wrap it or fold it around a wooden block.

That actually helps to achieve a flat surface, which means when you're sanding, you can get a really nice flat smooth finish.

Abrasive paper comes in different grades or grits, and that tells you how rough or smooth it is.

The grade or number corresponds to the size of the abrasive grit on the paper.

So a coarse, low grade abrasive paper, and here is a fine, high grade abrasive paper.

And you can actually see the coarse difference actually in a visual format just by looking at them.

You can see there is a clear difference between the coarseness of that abrasive paper.

So just to explain what I mean by these numbers.

So a 50 grit for example is a very coarse abrasive paper and an 800 grit is that extra fine abrasive paper, and all the numbers in between are kind of going between at those two figures, between the coarse and the extra fine.

So you choose the abrasive paper that you think is best fitted for what you need to do.

Low number grades are rough and remove a lot of material quickly, while medium grades offer smoothing things out.

Your high number grades, so your 800 grit, these are the ones that are used for more polishing.

Okay, quick check for understanding again on that then.

Which of the below abrasive paper grades would be best suited to remove a lot of material quickly? Is it A, 50, B, 100, C, 200, or D 400? Pause the video here.

Just to take a moment to think about your answer.

And the correct answer was A, 50.

Now sanding can also be carried out by power tools or machinery as well.

So here's an example of a power sander.

A power sander is a power tool that is often used in small-scale manufacturer.

And again, you may have used one of these in your workshop previously.

The abrasive pads are available in different grades.

Here's an example of a belt sander.

Now a belt sander is a machine that can remove more material in a shorter amount of time.

And a belt sander is benched, it's usually attached to a work surface.

Now when sanding, it is important that you always sand in the direction of the wood grain, and that's regardless of what sanding process you use.

So here's the example of some wood grain and you can see that the wood grain is traveling from left to right to or horizontally.

That would mean that we would also sand in those directions as well.

So the direction of the wood grain and the direction of the sanding is the same.

Okay, it's going to be over to you now to have a go at a few tasks.

The first thing I'd like you to do is to answer this question, why is it important to prepare timber for surface finishes? The second thing I'd like you to do then is just to explain the purpose of each of these tools by completing the table.

So you have a smoothing plane, abrasive paper, and a power sander.

So just explain the purpose of each one of those.

Okay, pause the video here to have a go at these tasks and good luck.

Okay, how did you get on? So the first thing I wanted you to do then was answer this question, why is it important to prepare timber for surface finishes? So let's look at an example answer for you to compare yours to.

Preparing timber before adding a surface finish is important because it helps the finish stick properly and look better.

If the timber is rough or dusty, paint or varnish might not go on evenly and could peel off.

Sanding the timber makes it smooth and clean, which gives a nicer finish and shows the grain better, and it also helps to protect the timber and make it last longer.

Hopefully you've got all of those key points, but again, just check it against your answer.

The second thing I asked you to do then was to complete to the table.

So let's again look at some example answers to this.

So the smoothing plane.

The smoothing plane is used to make the surface of timber flat and smooth by shaving off thin layers of wood.

Again, just compare that to your answer.

Abrasive paper is used to smooth the surface of timber by removing small imperfections, rough patches, and preparing it for finishing.

And lastly, the power sander that's used to quickly and efficiently smooth timber surfaces by removing rough areas and preparing the wood for surface finishes.

Just compare each one of those to yours and check you've got all the key points.

So the next thing we're going to look at then are timber surface finishes and the different options available to you.

Now, there are a range of different surface finishes that can be applied to timber, and choosing your surface finish will depend on factors such as the function of the final product, the aesthetics of the final product, and the type of timber you are applying the surface finish to.

All of these things will need to be considered when choosing which surface finish you will use.

Surface finishes such as oil, wax, stains, and varnish all enhance the appearance of a natural timber and the wood grain.

As you saw in that example I showed you of the table that had been finished.

So here's some examples of different finishes.

You can see there's an example of oil there, wax, stain, and also varnish.

I'm just gonna give you some more examples here.

Here are some examples of timber pizza cutter handles before a surface finish has been applied.

And here you can see the same handles after a surface finish has been applied.

They've also had the actual pizza cutter applied, but really just focused on the timber handles.

How have they changed? You can hopefully see that the natural wood grain has been enhanced by the surface finish.

You can actually see that wood grain much more clearly and it makes it look more beautiful.

It's also slightly dark in color as well.

Now in contrast, painting timber gives a solid color surface finish that hides the wood grain or timber below it.

So here's an example of a painted timber product.

You cannot see the wood grain at all, it's completely covered up.

Okay, quick question for you then.

Which of these surface finishes hides the wood grain of natural timber? Is it A oil, B, stain, C varnish, or D, paint? Pause the video here just to take a moment to think about your answer.

And the correct answer, it was D, paint.

Well done if you've got that right.

Let's start by looking at oils then.

Oils are liquids used to finish timber by soaking into the surface.

They enhance the timber's natural grain while offering protection against moisture and wear.

Now the key features of oils are these: they penetrate deep into the timber for long-lasting protection, they can enhance natural color and grain of the timber, they provide water resistance, but they're not fully waterproof though, it's just water resistance, they can require multiple coats and drying time between applications, and they are ideal for indoor furniture and surfaces like worktops or cutting boards.

Let's look at stains next.

Now, stains work by enhancing the appearance of the natural timber by adding color without hiding the grain.

And they can also make cheaper timber, like pine, look like more expensive timbers, such as mahogany.

So the key features of stains then, they penetrate the surface rather than sitting on top, unlike paint, but a little bit like an oil.

They come in water-based or oil-based formulas, but they're not a protective finish.

They usually still need a top coat in some way, such as a varnish.

Okay, quick check for understanding on those then.

What is the main purpose of using a wood stain on timber? Is it A, to completely cover the timber with a solid color, B, to add color while still showing the natural grain of the timber, or C, to create a thick protective layer on the surface of the timber? Pause the video just to take a moment to think about your answer.

And the correct answer was B.

So the main purpose of using wood stain on timber is to add color while still showing the natural grain of the timber.

Well done if you got that right.

Okay, next we'll look at varnish.

Varnish is a clear hard protective surface finish that sits on the surface of the timber.

So this isn't soaked in, it sits on the surface.

It's used to seal and protect timber while enhancing its natural appearance.

And varnish comes in gloss, satin, or matte finishes.

Now the key features of varnish are, it forms a tough durable layer on top of the timber, it enhances the natural grain and color without adding any color, it provides excellent resistance to water, heat, and scratches, you can have long lasting protection from varnish, it requires sanding between coats for best results, and it's typically used on doors, floors, and furniture.

Okay, and we'll also look at paint.

Now, paint adds color and creates a barrier against moisture, dirt and damage.

The key features of paint then.

It adds a solid color and hides natural grain.

It provides strong protection against moisture, UV light and wear.

It's easy to wipe clean and also to maintain.

It usually requires a primer and multiple coats for best results.

You can get it in gloss, satin, and matte finishes.

And it's commonly used for things such as decorative items, furniture and also exterior woodwork.

Okay, it's gonna be over to you now to have a go at a few more tasks.

First thing I'd like you to do is to compare paint and wood stain as a surface finish in terms of appearance and protection.

The second thing I'd like you to do is to explain the advantages of using a varnish on a wooden coffee table.

And the last thing I'd like you to do then is just to list the tools and materials you would need to prepare and finish your own product.

So your own product that you have made, what do you need to actually be able to prepare and finish your product? Okay, pause the video here to have a go at these tasks, and good luck.

How did you get on? Right, let's look at each one of these tasks then.

The first task I asked you to do was to compare paint and wood stain as surface finishes in terms of appearance and protection.

Let's look at an example answer.

Paint on wood stain are used to finish timber, but they create different effects.

Paint covers the surface of the wood completely hiding the grain and giving a solid color.

This can be useful for decorative purposes or when you want a bold color.

In contrast, wood stain adds color while still allowing the natural grain to show through, which is good for highlighting the beauty of the timber.

Paint forms a thick layer on top of the wood, providing good protection against moisture and wear.

Stain, however, soaks into the wood and doesn't offer much protection on its own.

Because of this stain usually needs a protective top coat like varnish to make the timber more durable.

Okay, just compare your answer to that, and check that you've got all the key points.

You'll also be phrased very differently and you may have also included some extra points that I've not included here.

But just make sure you've got the key points that are listed here.

The second task I asked you to do then was to explain the advantages of using a varnish on a wooden coffee table.

Again, let's look at a model answer.

Varnish is a good choice for a wooden coffee table because it provides a strong durable finish that protects surface from scratches, spills, and heat.

This is important for a coffee table, which is often used and might have drinks or hot items placed on it.

Varnish also helps to seal the wood, preventing moisture from soaking in and causing damage.

Another advantage is that varnish can enhance the natural look of the wood by making the grain stand out and giving it a glossy or satin appearance depending on the type used.

This means the table stays both attractive and hard wearing.

Again, just compare your answer to that one.

It will read differently, but have you got all the key points in there? And lastly, I asked you to list and explain your choice for the tools and materials you will use to prepare and finish your product.

If we look back at Andeep then, Andeep has suggested, "I will use a belt sander to ensure all of the excess wood on my wood joints has been removed and I've removed my pencil lines before using abrasive papers to polish the surface and make it even smoother.

I'm then going to apply a varnish to protect the timber from water and make it durable, as this product will be used both inside and outside." So he's explained which choice of tools and materials he's going to have, and then also he has considered the why part of the question.

He's explained why he has chosen these things.

Okay, your answer will be very different to Andeep's, but just make sure that you have actually explained your choices.

Alright, let's summarize today's lesson then.

Today we've been looking at surface treatments and finishes.

Surface finishes are coatings or treatments applied to a material or product.

Before applying any surface finish to timber, the timber must be properly prepared.

And surface finishes, such as oil, wax, stains, and varnish, enhance the appearance of natural timber and wood grain.

In contrast, painting timber gives a solid color surface finish that hides the wood grain or timber.

Thank you so much for joining me for the lesson today.

I will see you soon.