20x04 - Stagecoaches/Road Reflectors/Fire Baked Pottery/Custom Motorcycle Tanks

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Narrator:
an 1880s invention,

The cast-iron tub
was first marketed in america

As a horse trough
and a hog scalder,

Which could also serve
as a bathtub.

It was soon more popular in
the bathroom than the barnyard.

It's heat-retaining properties

Made a long and luxurious soak
possible.

The cast-iron tub
is one invention

That's got a lot of people
in hot water,

And that's what people like
about it.

Today, they make cast-iron tubs
from scrap metal --

Things
like old heating radiators,

Water pipes, manhole covers,
and even some car parts.

Recycling scrap iron

Is more energy efficient
and cheaper than mining it.

A powerful magnet
at the end of a crane arm

Lifts the heavy iron
from the scrap heap

And transfers it

To big trays
known as charging pans.

The charging pans deliver
the scrap to a center trough.

This trough is a scale.

It weighs the scrap
and releases it to a conveyer.

The scrap heads
into the bathtub factory.

Inside, it flows directly

Into an enormous
electric induction furnace

Heated
to more than 2,500° fahrenheit.

The scrap iron melts
into a pool of liquid metal.

They run this furnace
around the clock,

And it's always two-thirds full

So that newly-added scrap
melts quickly.

Huge hydraulic cylinders tip
the furnace forward.

The molten iron flows
into a ladle.

An overhead trolley

Carries the ladle brimming
with the hot liquid metal

To a holding furnace
which maintains its temperature

Until the next step.

They're now ready

To make a two-part casting mold
from sand

Using steel tub patterns.

To make one half of the mold,
they fill a tub pattern

With a mix
of moist sand and clay.

Hydraulic rams pack it down,

And the mix compacts

And takes the shape
of the pattern.

The clay is the bonding agent

That causes
the mix to hold the shape.

Once the rams retract,

The mold takes a trip
under some blades

That scrape off the excess sand.

Machinery then lifts this half
of the sand mold

Out of the steel pattern
and transfers it

To the other half of the mold
prepared earlier.

The two bathtub molds
now come together,

Leaving a small gap
between them.

The molten iron,
which has been transferred

To an automatic pouring system,

Flows into portals
in the top of the mold

And into the gap at the center.

The bathtub molds
then move to a cooling line,

And after chilling here
for about 20 minutes,

The iron inside solidifies.

Then, it's into a shaker device
that breaks apart the sand mold,

Revealing
the newly cast iron bathtub.

A robot retrieves the bathtub
and stacks it.

Next, an employee

Sprays specially-formulated
glass powder

Onto the tub.

It's an undercoat
for the enamel finish.

They bake the tub
until it's red-hot.

In the heat,

The glass powder melts
and adheres to the iron tub.

A hydraulic device
called a manipulator

Sets the tub on a pedestal.

The pedestal swivels

As they apply
two more ground-glass layers.

These are the enamel topcoats.

On contact, the glass mixture
melts onto the undercoat.

The layers of glass
form a permanent bond

With the iron casting.

Between coats, the tub cools,

And they send it back
into the furnace for a reheat.

They place a mask
in the base of the enamel tub.

The mask is like a stencil.

A robot blasts fine
alumina-oxide particles

Into the open areas of the mask.

This etches an abrasive finish,

Leaving a subtle pattern
on the surface of the bathtub.

It creates visual interest

And also provides
a non-slip surface.

The masks come in a variety
of patterns for different looks.

Whether it's a modern design

Or the traditional
claw-foot one,

These cast-iron tubs should have
no problem finding a home.

Narrator: the hopi,
a native american tribe

Living primarily
in northeastern arizona,

Are known for carving kachinas,

Wooden dolls
representing deities,

Elements in nature,
or the spirits of ancestors.

They are traditionally presented
in a dance ceremony

To the girls of the community.

Hopi kachina dolls
are cherished family keepsakes

Designed to teach hopi children
about the deities and spirits

Central
to their aboriginal traditions.

Besides ceremonial purposes,

Many hopi carvers produce
kachina dolls

For sale
to native art enthusiasts.

The carver uses
knives of different sizes,

Sharpening the steel blades
after every 10 or 15 minutes

To prevent dulling.

Kachina dolls are traditionally
made of cottonwood --

Not from the tree's branch,
but from its root.

The carver begins by shaving off
the thin outer bark.

With a straight cut
from one side to the other,

He shapes
a bit of the single feather

Which will adorn the top
of this doll's head.

He makes
a series of vertical cuts

To form the face and hairline.

He continues carving
the head form,

Then, with a wood-burning tool,

Burns in the square outline
of the face.

Now he shaves away wood
above and below

To make the face protrude.

He forms the face
in more detail...

...then picks up
the wood-burning tool again,

This time to delineate
the neckline...

...and the doll's robe.

Back to carving.

Now, with upward strokes,

He shaves off wood
to shape the neckline.

He takes a larger knife

And removes
bigger pieces of wood

To finish forming
the head feather.

Now he sands the wood

With progressively finer
sandpapers

To remove all the cut marks
left by his knives

And to refine the doll's shape.

With the doll
perfectly formed now,

It's time for the details
and decorations.

First, he sketches it all out
in pencil...

...then runs the wood-burning
tool along the lines.

He decorates the body,

Then moves on to the doll's hair
and facial features.

It's these details
that bring the doll alive.

What was a simple and ordinary
cottonwood tree root

Has gone through carving,
sanding, and burning

To become
an almost-finished kachina doll.

He now coats the entire surface
with clear varnish.

This seals the wood

To prevent it from absorbing
the paint he applies next.

About 40 minutes later,

The varnish is dry
and the painting can begin.

Traditionally, hopi carvers
made paint from natural pigments

Such as sand, plants,
and berries.

Today's carvers buy
ready-made oils or acrylics.

This carver dilutes
acrylic paint with water

To make it transparent.

This allows the natural beauty
of the wood grain

To show through the color.

After painting, he applies
a coat of clear varnish

To seal and protect the surface.

Some carvers have moved in a new
artistic direction -- bronze.

They use their wooden kachina
doll to produce a latex mold.

Then, with this mold,
cast a wax replica.

They dip the replica
in a substance

That hardens
into a heat-resistant shell.

Then, they put the shell in
a furnace to melt away the wax.

This leaves a cavity
in the shape of the doll.

They poor molten bronze
into the cavity,

And when the bronze
cools and solidifies,

They break the shell
to extract a bronze version

Of their kachina doll.

Instead of paints,

They apply chemicals
that color the metal --

A modern twist
on an age-old hopi art.

Narrator:
a mine-truck engine is a beast.

The most powerful ones pack
a brawny 24 cylinders,

Generating 4,200 horsepower.

Compare that to 200 horsepower

For a mid-sized car
with six cylinders.

But when they start
to show the strain,

It's time for a total rebuild.

After about 20,000 hours
of hauling heavy rock,

It's time for renewal.

Mine-truck engines
are routinely rebuilt --

Not just once,
but numerous times.

It's cheaper
than buying a new engine,

And it saves precious resources.

Each rebuild
is a massive undertaking --

Virtually every component
of this diesel engine

Will be remanufactured
or replaced.

As the team dismantles it,

They inspect each part
for wear and tear.

They take it down
to the immense crankshaft,

The heart
of this mine-truck engine.

With the crankshaft removed,

They pull the lengthy camshaft
out of the cylinder block.

With the engine now in pieces,

They clean every part
that's salvageable,

Including
the huge cylinder block.

A couple of hours soaking in
a hot sodium-phosphate solution

Removes the grease
and exposes the bare metal.

Any imperfections
are now more apparent.

Using a depth gauge,

A technician maps out flaws,
like this crack.

It will need to be filled,
and he makes a note of it.

Next,
a high-speed milling tool

Carves off a thin layer
of the steel,

Taking the cylinder block's
finish from grimy-gray

To bright and shiny.

It also smoothes away
any unevenness

To create a uniform surface

For sealing gaskets
around the cylinders later.

After the intensive machining,

The cylinder block
looks like new.

It's back to the crankshaft now.

It, too, has undergone
an extensive cleaning.

Machinery grinds
the outside diameter

To a precise tolerance --

Equivalent to one-twentieth
of a human hair.

This will allow new,
thicker bearings to fit to it.

The team clamps weights
to the machine crankshaft.

These weights mimic
the load of engine parts,

Like pistons and rods,

As they now balance
this critical part.

The crankshaft rotates,

And sensors detect vibrations
and pinpoint the problem.

After more grinding
in these locations,

They test it again to confirm
the crankshaft is balanced.

Back to the camshaft now --

A member of the crew
uses a black marker

To highlight wear patterns.

A grinder evens out the wear,

And it also machines
the profile of each lobe

As it follows
a metal camshaft master.

The black-marker lines vanish
as the wear lines are smoothed,

And the profile of the camshaft
is improved.

A major clean-up
also transforms the rods

That connect
the piston to the crankshaft.

A technician then places the rod
in a special honing machine

And activates it.

Four arms with gritty ends
grind the inside of the rod-head

As the technician moves the rod
back and forth.

This sizes the inner diameter
to enable the rod

To fit
to the other revamped parts.

Once all the parts
have been cleaned and machined,

The engine is ready
for reassembly.

Using a crane, a technician
lowers the crankshaft

Back into the cylinder block.

He secures the crankshaft
at one end

With a metal bracket
called a main cap.

There are actually
nine main caps in total.

He gives the crankshaft a spin

To confirm
that it rotates freely

Before installing the rest.

With a piston now attached
to one end of a connecting rod,

He slides the other end
into a slot

In the cylinder block.

This particular engine
is a 16-cylinder one.

It's considered midsize
for mining trucks.

Once the gaskets have been fixed
to the cylinder block,

They bolt
the cylinder heads to it.

There are hundreds of parts
in one of these monster engines,

And it takes 700 person hours
for one rebuild.

With this mine-truck engine
now fully assembled,

They hook it up to a dynamometer
to measure engine performance.

They run at full tilt to confirm
that it's firing all cylinders

And performing to the max.

This rebuilt mine-truck engine

Is ready to go
back into service.

Strong and heavily built,
this nine-ton diesel engine

Should pull its own weight
and then some.

Narrator:
music, photographs, documents --

What used to take up shelf space
in our homes offices

Can now be stored
on a tiny memory card

Or flash drive.

You can save your files on it,

Take them out of the device
and transport them anywhere,

As well as delete data
you no longer need.

A memory card fits into a slot
in your digital device.

A flash drive plugs
into a usb port.

The key component
of both formats --

A memory chip,

Produced in a factory

That's 1,000 times cleaner
than a hospital operating room.

It all begins with the wafer --
a thin disc of pure silicon,

A non-metallic natural element
that conducts electricity.

An automated container system

Moves the wafer through
more than 800 operations.

At each stop,

The wafer receives
one of several layers

Of non-conductive materials,
such as silicon dioxide,

And conductive materials,
such as copper.

The machines coat the layer
with light-sensitive fluid,

Then apply uv light
through a glass stencil

Of the complex pattern
of electrical circuitry.

The exposed areas of fluid
chemically react,

Locking the material
directly underneath

Into the circuitry pattern.

Chemical baths then remove the
surrounding fluid and material,

Leaving
only the layer of circuitry,

Electrical pathways


Than a human hair.

A robot tests the circuitry for
every memory chip on the wafer.

A single wafer,
measuring 12 inches in diameter,

Yields hundreds of memory chips.

The goal is to make those chips
as small as possible.

In this industry,

It's all about maximum memory
in minimal space.

That's why this operation thins
the chips

By grinding away
two-thirds of the silicon

From the backside of the wafer.

And one last step
before cutting the wafer

Into individual memory chips --

This machine applies tape

To hold
the separated chips together.

A computer-guided saw slices
the chips apart.

Cutting silicon
is like cutting glass --

It requires
a diamond-edge blade.

In the next step, a robotic arm,

Following the wafer map
generated earlier,

Picks up the chips
which pass testing

And attaches each one
to a fiberglass lead frame.

The term lead refers
to the frame's pins,

Which connect the chip
to the digital device.

Another robot wires the chip
to the lead frame

With gold thread that's about
the width of a human hair.

Gold is very conductive,
so now the pathway is complete.

Electricity will travel
from the chip's circuitry,

Through the gold thread,
to the pins, to the device.

After a machine seals
the chip in plastic,

Workers gently snap them apart

And insert them
in memory-card housings.

The plastic and metal housing
is for a memory card format

Known as compact flash.

A small, automated press

Locks the two halves
of the housing together.

The next station labels
the front of the housing.

Every single memory card
undergoes testing

For both function and speed.

A laser machine
etches product information

Into the back of the housing.

These are another format
called secure digital, or sd.

They're assembled and labeled

Just like
the compact flashcards.

When the finished memory cards
come off the assembly line,

Workers conduct
a final, visual inspection.

On the flash drive
assembly line,

Much the same process.

A robot puts 20 lead frames
on 20 circuit boards.

Then, a worker positions


Which a soldering machine bonds
to the circuit boards.

The final step --
electronic testing,

To make sure
the usb connection is working,

And via the circuit board,
talking to the chip.

The flash drives are now ready
to go into individual housings.

This model has
a two-part plastic housing,

Which pivots in and out
of a plastic case,

That can conveniently
be attached to a key chain

Or a lanyard
for easy portability.

Flash drive or memory card,

Storing your digital effects
is just a click away.

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about the show,

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