All language subtitles for S04E04 - Conga Drums; Metal Plating; Buttons (576p AMZN WEB-DL x265 Garshasp)_track4_[eng]

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Narrator:
Today on "How it's made"...

Conga drums...

...Metal plating...

...And buttons.

The conga drum may be a staple
Of latin-american music,

But it was developed
From an ancient african drum

Made from an animal skin

Stretched over
A hollow tree trunk.

Today, they stretch the hide

Over a wood
Or fiberglass cylinder.

As you're about to see,

Making congas takes plenty
Of hands-on skill.

These congas are made of ash,

A wood that has good acoustics.

That means
Sound resonates off of it

Rather than being absorbed
Into it.

First, the drum maker
Cuts the curved slats

That will form the drum's body,
Called the shell.

He traces a slat-shaped template

On a rectangular piece of wood.

Then, using a band saw,
He cuts along the trace line,

Creating a curve on the outside
And inside surfaces.

Then he moves to a bench saw,

A saw whose blade can be
Adjusted to different angles.

He clamps the piece
Onto a template

And angles the edge.

He flips the piece over...

...And angles the other edge.

The drum maker applies
Carpenter's glue to both edges

And clamps the slats
Together in a circle

On a specially designed form.

The number of slats
Per drum varies,

Depending on the diameter
Of the shell.

The larger the diameter,
The lower the conga's sound.

The glue dries in 24 hours.

It comes off the form

Looking like this bongo shell,
But taller.

The drum maker now mounts
The dried shell on a wood lathe.

Using a tool called
A wood gouge,

He shears off
About .2 of an inch,

Rounding the outside
Of the shell.

Then he uses a series
Of woodworking tools

To add decorative detailing.

Once that's done,
He smoothes the shell's surface,

Using three progressively
Finer grains of sandpaper.

Then he either leaves the wood
Its natural color or stains it.

A thick coat of oil-based
Lacquer protects the wood

From both dryness and humidity.

Now for the essential hardware.

First, side plates
Made of chrome-plated steel.

Their job is to anchor
The drum's animal-skin head.

They're bolted to the shell.

Next, the drum maker
Feeds a steel strip

Through a bending machine.

Its high-pressure rollers
Curve the strip,

Forming the drum's rim.

Then he rivets v-shaped
Steel pieces onto the rim.

Elsewhere in the workshop,

They prepare the cowhide that
Will become the drum's head.

First they soak it

In a corrosive bath
Of cold water and lime.

This literally burns the hair
Off the hide.

After two or three days,

They remove the skin and scrape
Off any stubborn hairs.

Then they stretch it
Over a circular frame,

Leaving it to dry
At room temperature

For a couple of days.

After chrome-plating the rim,

It's time
For the final assembly.

They stretch the head
Over the shell

And clasp it in place
With the rim.

They hook the v's
To the side plates,

Then adjust the tension
To tune the instrument.

The last step is to trim off
The excess skin.

Now the musical handiwork
Can begin.

Narrator: plating is a layer
Of metal coating an object

Made of a different type
Of metal.

The purpose can be decorative,
As in silver plating,

Or practical.

With industrial parts,
For instance,

Zinc or cadmium plating

Prevents the underlying metal
From rusting,

While nickel or chrome plating
Protects against wear.

You can plate
Almost any type of metal.

Let's follow some
Steel aerospace parts

As they're about to be plated
With cadmium

To make them
Corrosion-resistant.

For the plating metal
To bond properly,

The steel surface must be free
Of contaminants

Such as oil and grease.

Workers suspend the parts

Over a vat of boiling
Chemical solvents.

As the hot vapor comes in
Contact with the colder metal,

It condenses,
Dripping down into the vat

And taking any contaminants
Along with it.

The remaining solvent
Residues evaporate,

Leaving the parts
Squeaky-clean and dry.

Next, a worker
Wearing protective clothing

Sandblasts the parts
With aluminum oxide powder,

A strong abrasive.

This roughens up the surface

So that the plating metal
Will adhere better.

The most common plating metals
For industrial purposes

Are zinc, chrome, and nickel.

Think motorcycle parts
Or sink faucets.

Decorative items,
On the other hand,

Are most likely to be plated
In tin, brass, gold, or silver.

Traditional tea sets,
For instance,

Are often made of silver-plated
Copper or zinc.

The plating process
Is called electroplating

Because the key is electricity.

They start by tying strands
Of copper wire

To a copper support frame.

Copper is the best metal
For conducting electricity.

Then they attach the steel parts
They'll be plating.

When they hook up the support
To an electric current,

Electricity will run from
The support through these wires

Right to the pieces.

They do the electroplating
In a tank.

After filling it with water,

They add a handful of chemicals
To help conduct electricity,

Because water alone
Won't conduct it sufficiently.

Along the sides of the tank,
In bags, are metal baskets.

They contain bars or balls
Of the plating metal --

In this case, cadmium.

Workers connect the support
Frame with the steel parts

To the negative terminal
Of an electric source --

The baskets of cadmium
To the positive terminal.

Then, they switch on
A steady d.C. Current

No stronger than six volts.

The electricity dissolves
The cadmium,

Placing the particles
With a positive charge.

They travel through the water

And attach themselves to the
Negative-charged steel parts.

This creates a smooth and even
Layer of cadmium.

Thin plating requires
Just a few minutes in the tank.

Thick plating, several hours.

Then workers rinse the parts
In water for about a minute

To remove the chemical residues.

To make the parts
Even more rust-resistant,

Workers immerse them
In a series of compounds.

This triggers a chemical
Reaction in the plating,

Enhancing its ability
To withstand corrosion.

This reaction, however,
Changes the color.

A final rinse in hot water,

And this cadmium-plated steel
Aerospace part is finally ready.

From start to finish,

The process has taken
About 90 minutes.

To plate with chrome or gold,

They have to use
A chemical compound

Containing gold or chromium.

That's because electricity
Can't dissolve

Solid chromium well enough,

And it can't dissolve solid gold
At all.

The compound dissolves
In the bath like salt,

But then solidifies

Once it reaches
The object being plated.

Metal plating is very durable,

But if subjected
To a lot of wear and tear,

The object will eventually
Have to be replated.

Narrator: have you ever wondered
Why men's buttons

Are traditionally
On the right side of a garment

And women's on the left?

Legend has it
That this enabled a man

To unbutton his coat
With his left hand

While drawing a sword
With his right.

Wealthy women, meanwhile,

Had their buttons
Sewn on the left side

To make it easier
For their right-handed maids

To dress them.

One way to make plastic buttons

Uses a multilayer sheet
Of synthetic resin --

Hence the industry term,
Sheet buttons.

Workers start by mixing
Liquid polyester resin

With a catalyst to gel it.

They pour the material
Into a revolving drum,

Which disperses it evenly.

They spray a solution containing
An ultraviolet pigment

On this first layer only.

You'll see why later on.

For this particular model,

They make grooves in the resin
While it's still malleable.

This will create a design.

After about five minutes,

The resin gels and they can mix
And add a second layer

In a different color.

Besides building up
The thickness of the sheet,

The resin flows
Into the first layer's grooves,

Creating a design
Of contrasting lines.

Once this second layer gels,

They mix and pour in
A third color.

The drum spins
For another 10 to 15 minutes

Until all layers cure.

A resin sheet can be comprised

Of up to 4 different
Color layers.

Workers can now
Remove the sheet.

It's hardened enough
To be cut into buttons,

But it's still flexible enough
Not to crack when cut.

They feed each sheet
Into a press

That's outfitted with the die

For that particular
Button model.

The press punches out circles
In the diameter of the button.

These circles are called blanks.

Here, you can see
The different color layers.

The blanks move on
To the machining center,

Where they'll be transformed
Into buttons.

Automated equipment
Loads them onto carousels

With the back of the blank
Facing outward.

How does the loader know
Which side is which?

Remember
That ultraviolet solution

The workers sprayed onto
The first layer of resin?

A u.V. Detector scans each blank

To make sure the first layer
Is facing upward.

If it isn't, the machine
Rejects the blank,

Then flips and reloads it.

The carousels first
Run the back of the blank

Against a series
Of cutting heads.

The heads are changed according
To the model being produced.

For this one, the heads
Gradually carve a curved back.

The equipment then transfers the
Blank onto a second carousel,

Exposing the front side
This time.

Again, a series of cutting heads

Gradually carve
The front of the button.

The shape of this model

Exposes the different
Color layers underneath,

Creating a veined effect.

The last cutting head
Drills the holes.

Here, you can see
The full progression

From blank to button.

Now they polish the buttons
For several hours

In drums containing abrasive
Ceramic stones and pumice.

Then workers flush the drums
With water.

The heavy polishing stones
Sink to the bottom

While the lightweight buttons

Float to the surface
And spill out.

The buttons then go into drums
That contain silicon wax

And thousands
Of tiny wooden pegs.

While the drums spin,
The pegs act as a carrier,

Distributing
An even coat of wax.

As the buttons exit the drums,
The pegs are screened out.

From here, plain buttons
Are often custom-dyed

To match fabric swatches

Provided by clothing
Manufacturers.

Narrator: you've seen
How they manufacture

Some types of plastic buttons,

Just a few of the many styles
On the market.

There are several different ways

To produce these handy
Little fasteners.

So, forgive us
If we buttonhole you

To stay tuned
And watch some more.

Archeologists
Have unearthed bone buttons

Dating back
To prehistoric times.

The ancient greeks and romans
Used buttons

To fasten and decorate
Their clothing.

Europeans wore buttons
Strictly for adornment

Until about the 1200s.

That's when fitted garments
Became the trend,

Fastened by a long row
Of buttons down the front.

The rich wore buttons
Made of silver or gold,

Sometimes set
With precious gemstones.

Ordinary people wore buttons
Made of bronze or wood.

This is another way
To make plastic buttons

Using polyester resin.

Only instead of turning it
Into sheets,

They pour the resin
Into long metal tubes.

Here, they're mixing
Two different colors

To create a design
In the plastic.

The tubes go into an oven,

Where they bake at 212 degrees
Fahrenheit for about an hour

Until the liquid resin hardens.

Once the tubes cool off,

Workers remove the contents.

These long resin rods
Will become

What the industry calls
Rod buttons.

The rods go into a machine
Called the slicer.

Its sharp carbide blade
Chops the long rods

Into button-sized blanks.

Here's what that looks like
In slow motion.

It's no use showing you this
At regular speed.

It would be but a blur.

This machine cuts
Up to 700 blanks per minute.

Blanks cut from resin rods

Run through
The same machining center

As those cut from resin sheets.

In the last segment,

We showed you the machining
Steps in slow motion.

Here's what they look like
At actual speed.

Any type of button
Can be engraved

With a company name or logo.

They do this

Using a computer-programmed
Laser machine.

The laser beam burns
The lettering into the plastic.

Workers visually inspect
The finished buttons

To make sure that none
Have defects.

A third way
To make plastic buttons

Is a method called
Thermoset compression,

A technique that combines
Both heat and pressure

To mold the button's shape.

As we see here in slow motion,

The raw material
Isn't liquid resin,

But rather melamine powder.

A pill-making machine --

The kind pharmaceutical
Companies use --

Compresses the powder
Into pill-shaped blanks.

Here's what that pill-making
Action looks like

At actual speed.

To transform these pills
Into buttons,

Workers load them onto a press.

The press uses high pressure

To force each pill
Into a button mold

For a period
Of 40 to 60 seconds,

Depending on the size
Of the button.

At the same time,

It heats the mold
To 325 degrees fahrenheit.

This bakes the melamine
Into hard plastic.

They cool the molded buttons
In a basin of cold water.

Some specialty buttons
Will be gold-plated,

But not before soaking
In a chemical bath

To clean their surface

So that the plating
Will bond well.

As a rule, only materials
That conduct electricity

Can be metal-plated.

Plastic, of course,
Is nonconductive.

This company has managed
To devise a way

To gold-plate plastic buttons.

Exactly how
Is a closely guarded secret

It's not willing to divulge.

After plating the buttons
In copper, a 12-hour process,

They plate them in nickel,

Which takes
Just a couple of minutes,

And finally, in 24-karat gold,

Which takes just a few seconds.

A mere one ounce of gold

Is enough to plate
180 pounds of buttons.

Thermoset compression buttons
Are a lower-end product

Used primarily for uniforms.

Sheet buttons and rod buttons
Are higher quality,

The standard choice for everyday
And higher-end clothing.

If you have any comments
About the show,

Or if you'd like to suggest
Topics for future shows,

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