How It's Made

Narrator: TODAY, ON "HOW IT'S MADE"...

FOOTBALLS...

...ELECTRIC-GUITAR AMPLIFIERS...

...MARBLES...

...AND AIRPLANE PROPELLERS.

IN 1869, PLAYERS IN THE FIRST FOOTBALL GAME USED A ROUND BALL,

LIKE IN SOCCER.

IT WAS TOUGH TO CARRY AND AWKWARD TO THROW,

SO THEY CHANGED IT TO LOOK MORE LIKE A WATERMELON.

THE CURRENT SHAPE ENABLES A BETTER GRIP

AND PASSING ON AN ARC THAT'S UNIQUE TO FOOTBALL.

A LOT OF PEOPLE HANDLE A FOOTBALL

BEFORE IT EVER GETS TO THE FIELD.

THEY START WITH COWHIDE.

FOOTBALLS ARE TRADITIONALLY MADE OF THIS LEATHER

BECAUSE IT WEARS WELL OVER TIME.

WITH A DIE, A WORKER CUTS OUT THE FOUR SECTIONS

THAT MAKE UP THE BALL'S SKIN.

A STAMPING MACHINE THEN BRANDS THE SKIN WITH THE COMPANY LOGO.

THEY MAY PUT OTHER MARKINGS ELSEWHERE ON THE BALL,

DEPENDING ON THE DESIGN OF THE MODEL THEY'RE MAKING.

EACH OF THE SECTIONS GOES INTO A MACHINE

THAT TRIMS THE PIECES' COMBINED WEIGHT DOWN TO SPEC.

TO STRENGTHEN THE SKIN,

A SEAMSTRESS SEWS COTTON AND VINYL LININGS

ONTO ALL FOUR SECTIONS.

THEN SHE PLACES THEM IN A DIE

THAT POSITIONS THEM FOR ANOTHER SET OF MARKINGS.

THESE FOUR WHITE LINES WILL FORM TWO STRIPES

WHEN THE SECTIONS COME TOGETHER.

THIS IS PURELY AESTHETIC

AND VARIES ACCORDING TO THE FOOTBALL MODEL.

NOW IT'S TIME TO SEW THE TOP SECTIONS TOGETHER

AND THEN THE BOTTOM ONES TO EACH OTHER.

EXACTLY HOW MANY STITCHES THIS TAKES

IS THIS COMPANY'S CLOSELY GUARDED SECRET.

THIS PRESS MAKES A HOLE IN ONE OF THE TOP SECTIONS

FOR THE AIR VALVE.

THEY MAKE EIGHT HOLES IN THE TOP SECTIONS

FOR LACES THAT WILL HOLD THE SKIN TIGHTLY

AROUND AN INFLATED BAG CALLED A BLADDER.

TO JOIN THE BALL'S TOP AND BOTTOM SECTIONS,

THE SEAMSTRESS FIRST CUPS THEM

AND THEN JOINS THE EDGES TOGETHER.

SHE SEWS THE LEATHER INSIDE OUT

TO MAKE THE STITCHES LESS VISIBLE.

LATER, WORKERS WILL TURN THE SKIN RIGHT-SIDE OUT

BY REACHING THROUGH THE OPENING BETWEEN THE LACE HOLES.

THIS IS ALSO WHERE THEY'LL INSERT THE BLADDER.

IT'S IMPORTANT TO FLATTEN THE FOUR SEAMS.

TO DO THIS, A WORKER PLACES EACH ONE ON A WHEEL,

AS A ROLLER PASSES OVER THE TOP.

THIS KEEPS THE BALL FROM BEING BUMPY

WHEN THEY STRETCH THE SKIN OVER THE BLADDER.

A 15-SECOND STEAM SOFTENS THE LEATHER

AND MAKES IT EASIER TO MANIPULATE.

A CONCAVE PRESS FLATTENS THE SEAMS AT THE TIPS.

THIS WILL ALSO KEEP THE BALL SMOOTH WHEN THEY INFLATE IT.

TIME TO TURN THE SKIN RIGHT-SIDE OUT.

THE WORKER PLACES IT ON A METAL BAR,

THEN, REACHING THROUGH THE OPENING BETWEEN THE LACE HOLES,

HE GRABS THE OTHER SIDE OF THE SKIN AND PULLS IT THROUGH.

THEN HE RUNS THE BAR ALONG THE INSIDE

TO RESHAPE THE SKIN.

THE BLADDER IS MADE OF POLYURETHANE, A TYPE OF PLASTIC,

WITH A VINYL PATCH REINFORCING THE LACING AREA.

AFTER SQUEEZING THE BLADDER INSIDE THE SKIN,

A WORKER SNIPS OFF THE END OF THE AIR VALVE

TO KEEP IT OUT OF THE WAY.

THEN SHE INFLATES THE BLADDER A BIT

TO MAKE IT RIGID ENOUGH FOR LACING.

AFTER STEADYING THE BALL WITH CLAMPS,

SHE USES AN AWL TO THREAD THE LACE THROUGH THE HOLES --

JUST ONE VINYL LACE, MEASURING FOUR FEET.

IT WORMS THROUGH BOTH SIDES AND THEN DOWN THE CENTER

AND THROUGH ALL THE HOLES ONCE AGAIN.

THE LACING IS SPACED ABOUT A HALF INCH APART --

WIDE ENOUGH TO COMFORTABLY GRIP

FOR THAT MAGIC PASS YOU'VE GOT IN MIND.

NEXT, WORKERS TEMPORARILY OVERINFLATE THE BALLS.

STEEL MOLDS SURROUND THEM

TO ENSURE THEY'LL ASSUME THE CORRECT SHAPE.

AFTER 90 SECONDS, THE EXTRA AIR SEEPS OUT.

FINALLY, THE FACTORY INSPECTS THE BALLS

TO ENSURE THEY'RE UP TO STANDARD.

FULLY INFLATED, A BALL MUST WEIGH NO MORE THAN 15 OUNCES.

IT SHOULD MEASURE 21 1/2 INCHES THROUGH THE MIDDLE

AND 28 INCHES AROUND BOTH ENDS.

AFTER A FIVE-DAY MANUFACTURING PROCESS,

THESE BALLS ARE READY FOR THE FIELD.

Narrator: YOU HAVE TO PLUG AN ELECTRICAL GUITAR INTO AN AMPLIFIER

IF YOU WANT IT TO BE MORE THAN BARELY AUDIBLE.

A GUITAR AMPLIFIER IS TYPICALLY A BOXED UNIT,

CONTAINING AN AMP TO BOOST THE ELECTRONIC SIGNAL

AND A LOUDSPEAKER.

SOME AMPLIFIERS

USE STATE-OF-THE-ART SILICON-CHIP CIRCUITRY,

WHILE OTHERS USE TRADITIONAL VACUUM TUBES.

THE AMP'S ELECTRONICS ARE HOUSED INSIDE A METAL CHASSIS.

THIS MODEL'S CHASSIS IS MADE FROM A SHEET OF METAL

THAT'S LESS THAN .04 INCHES THICK.

A COMPUTER-GUIDED MACHINE CALLED A TURRET PUNCH

CUTS THE CONTOUR

AND PIERCES A SERIES OF HOLES AND SLOTS

FOR THE CONTROLS.

A WORKER THEN USES A COMPUTER-GUIDED BENDER

TO SHAPE THE CHASSIS CUTOUT.

ELSEWHERE IN THE FACTORY,

THE AMP'S CIRCUIT BOARD TAKES SHAPE.

IT'LL GO INSIDE THE CHASSIS.

A COMPUTER-GUIDED DRILL MAKES TINY HOLES

IN A LAMINATE BOARD THAT'S COATED WITH COPPER.

THE HOLES ARE FOR THE BOARD'S VARIOUS ELECTRONIC COMPONENTS.

AN AUTOMATED SILK-SCREEN PRINTER

NOW APPLIES A DIAGRAM OF THE ELECTRICAL CIRCUITRY

IN AMMONIA-RESISTANT INK.

THEN THE BOARD GOES INTO A MACHINE CALLED AN ETCHER,

WHICH USES AMMONIA TO DISSOLVE THE COPPER COATING.

COPPER SHIELDED BY THE INK DIAGRAM STAYS INTACT.

THE MACHINE THEN RINSES THE BOARD

WITH SODIUM HYDROXIDE TO DISSOLVE THE INK,

LEAVING BEHIND JUST THE CIRCUITRY DIAGRAM AND COPPER.

THIS COPPER CONFIGURATION WILL CONDUCT ELECTRICITY

TO THE CIRCUIT-BOARD COMPONENTS.

AUTOMATED MACHINES INSERT THE SMALLER COMPONENTS.

HERE'S WHAT THAT LOOKS LIKE IN SLOW MOTION...

...AND AT ACTUAL SPEED.

AS A WORKER PROVIDES COUNTERPRESSURE,

A MACHINE FOLDS OVER THE LEAVES OF SOME LARGER COMPONENTS

TO SECURE THEM TO THE BOARD UNTIL THEY'RE SOLDERED.

WORKERS THEN INSTALL LARGE, IRREGULAR PARTS BY HAND,

AMONG THEM -- THE SOCKETS THAT HOLD THE TUBES

WHICH POWER THE AMP...

...THE RIBBON CONNECTERS

THAT JOIN DIFFERENT AREAS OF THE CIRCUIT BOARD...

...AND THE WIRES THAT CONNECT EXTERNAL COMPONENTS

TO THE BOARD.

THE FACTORY PERMANENTLY AFFIXES EVERYTHING IN ONE SHOT,

USING A PROCESS CALLED WAVE SOLDERING.

THE CIRCUIT BOARD RUNS THROUGH A BATH OF MOLTEN TIN AND LEAD.

IN JUST A COUPLE OF SECONDS, THE LIQUEFIED METAL HARDENS,

BONDING THE COMPONENTS SECURELY.

BACK TO THAT STEEL CHASSIS

WE SAW THEM BEND INTO SHAPE EARLIER.

SINCE THEN, THEY'VE PAINTED IT BLACK.

WITH A SILK SCREEN PRINTER,

THEY APPLY THE CONTROL MARKINGS, LOGOS, AND OTHER INFORMATION.

THEY BEGIN THE FINAL ASSEMBLY.

FIRST, THEY SCREW THE CIRCUIT BOARD INTO THE CHASSIS.

THEN THEY PLUG THE PREAMP TUBE

INTO THE APPROPRIATE SOCKET ON THE BOARD.

THIS TUBE BOOSTS THE ELECTRICAL SIGNAL COMING FROM THE GUITAR

AND FEEDS IT TO THE OUTPUT TUBES,

WHICH UP THE VOLTAGE LEVEL,

MAKING THE SIGNAL STRONGER AND LOUDER.

AFTER INSTALLING CONTROL KNOBS

AND COVERING THE BOTTOM OF THE CHASSIS,

WORKERS INSERT AND CLAMP THE OUTPUT TUBES,

THE NUMBER OF WHICH USUALLY VARIES

ACCORDING TO HOW MANY WATTS OF POWER

THE AMP IS DESIGNED TO PRODUCE.

THE CHASSIS HOUSING THE ELECTRONICS GOES INTO A BOX.

THIS FACTORY BUILDS ITS BOXES

FROM HIGH-GRADE BALTIC BIRCH PLYWOOD,

BUT OTHER COMPANIES OFTEN USE DOMESTIC PLYWOOD, MDF,

OR EVEN PLASTIC.

AFTER COVERING THE BOX IN LEATHERETTE

AND ADDING CORNER REINFORCEMENTS,

THEY INSTALL THE TWO REMAINING COMPONENTS --

THE SPRING REVERB...

...AND THE SPEAKER.

AS THE GUITAR'S ELECTRICAL SIGNALS RUN THROUGH THE AMP,

PART OF THE ELECTRICAL SIGNAL

DIVERTS TO ONE END OF THE SPRING, VIBRATING IT.

THE SPRING'S OTHER END PICKS UP THIS VIBRATION

AND SENDS IT BACK THROUGH THE AMP AS A DELAYED SIGNAL.

THAT REVERBERATION COMBINES WITH THE ORIGINAL SIGNAL