Original subtitles

Please don't try anything you

are about to see at home.

We're what you call experts.

Narrator: On this episode of

"mythbusters"...

Two, one, go.

[ Laughs ]

Awesome.

Narrator: Adam and Jamie get

down and dirty...

I've never seen anything like

that.

Narrator: Testing that an

explosion inside a sewer...

[ Laughs ]

That sewer's getting pretty

of methane!

Narrator: Turns manhole

covers into missiles.

Suspense is killing me.

[ Tires screech ]

Narrator: Then kari, Tory,

and Grant take on the fan

fable...

Love when i get to drive.

Narrator: That truck

bedliner is indestructible with

car crashes...

I'm okay.

Narrator: Angry attack

dogs...

[ Dog snarls ]

and an end-with-a-bang

finale, can bedliner really save

your life?

A lot of people ask me, "do

you ever get tired of blowing

stuff up?"

And i tell them no.

Narrator: Who are the

mythbusters?

Adam savage...

Ah!

Am i missing an eyebrow?

Narrator: And

Jamie hyneman...

Things are gonna start to get

a little crazy in here.

Narrator: Between them,

more than 30 years of

special-effects experience.

Together with kari Byron...

Time to wreck this car.

Narrator: Tory belleci...

Oh!

We survived!

Narrator: And

Grant imahara...

Save yourselves!

Narrator: They don't just

tell the myths.

They put them to the test.

Captions by vitac... www.Vitac.Com

so is every story we do an

excuse for you to wear a funny

hat?

You should know the answer to

that by now, although

specifically in this story it's

quite apt, because we're doing a

myth about sewers.

Sewers?

Well, specifically explosions

within sewers.

You mean like from a methane

build-up?

Yes, but it's not just about

methane explosions.

It's about during the methane

explosion, do the manhole covers

on the street, above the sewer,

get blown high into the air?

That sounds like a classic.

It's perfect for us.

I totally agree.

Narrator: It's no myth that

the decay of waste inside sewers

makes them the perfect breeding

ground for combustion.

However, could a stray spark

trigger an epic explosion and

send manhole covers

skyrocketing?

Could a manhole ever turn

missile?

What's the plan?

Well, it seems clear to me

that this myth has to end with

us testing it full scale.

We need full-size manhole covers

over a real sewer.

I agree.

But you know what?

Before we lock in on a full-size

plan, let's do a small-scale one

first and see if we can learn

anything.

Sounds like a good idea.

This ought to do it.

Narrator: So to find out if a

methane kaboom can make manholes

fly, the mythbusters get their

minds into the sewer.

This is a schedule-80 steel

pipe, and I'm about to make it

into a miniature sewer with a

viewing port all along one side,

which is hopefully going to be

explosion-proof.

Narrator: This cumbersome

pipe should perfectly replicate

a sewer in miniature, but with

great weight comes great

responsibility.

[ Chuckles ]

[ Grunts ]

You see us build a lot of

stuff on this show.

And a lot of times it's kind of

like, yes, we are really just

figuring it out as we go along.

Ah, it's beautiful.

But when you're build something

this heavy and substantial, you

can't quite do it that way.

You actually have to plan two or

three steps ahead.

Let's weld this puppy down.

'Cause everything you're doing

and everything you're going to

do is going to require moving

hundred of pounds of steel

around.

Oh, this is heavy.

Not only can it make it

logistically difficult, but

fingers can be lost, eyes can be

poked out.

It's dangerous.

Watch your fingers.

It's lovely.

Yeah, it is.

I can't believe this is a small

scale.

[ Chuckles ]

Narrator: It may be big...

Perfect.

Narrator: but to

withstand a methane explosion,

it has to be.

And to complete its authentic

aesthetic, Jamie needs to make

these.

That's a manhole cover.

So, clearly, in a sewer,

there's all sorts of waste...

Human waste, household waste.

And those wastes produce the

dangerous gases that can lead to

an explosion.

That's not how we're creating

our gases.

No, we're just calling up the

welding store and bringing in

some methane and pumping it in.

But remember, methane is a

little tricky.

It requires a precise ratio of

air to gas in order to explode.

9% in 3...

And that's exactly the ratio

that we'll be using today.

[ Both laugh ]

Why?

Because this myth isn't really

about the circumstances that

lead to an explosion.

It's about what happens

afterwards.

The question we're answering is,

will those manhole covers fly

sky high?

Narrator: To find that out,

Adam and Jamie are going to test

a series of potentially

explosive sewer scenarios.

The first test is the most

standard sewer setup... an

open-ended system.

Here's how this procedure is

gonna go down.

First, we fill our chamber with

this... methane... exactly

.12 cubic feet or a

stoichiometry of 9.5% gas to air

by volume.

All right, you ready?

I'm gonna turn on the gas.

I'm ready.

Okay.

That gas will flow into the

chamber until it's the correct

amount, then we shut off all the

valves.

Then we mix the air and the gas

with this... this little whisper

fan.

We turn on this fan for exactly

two minutes, let the air and the

gas get together.

It's a nice-looking rig.

Yeah.

That might be in the running

for the heaviest small-scale

thing we've ever built.

[ Chuckles ]

At that point, we will plug

in this neon transformer, set

it a-spark, and hopefully...

Bchrrrr! Psh!

Bchrrrr! Psh!

Bchrrrr! Psh!

Getting the manhole-cover

launches of our dreams.

Narrator: But will the free

flow of air and gas in the

open-ended sewer mean the

manholes fly?

This is drain disaster,

open system, in three, two, one.

Go.

[ Chuckles ]

That was totally boring.

It was like...

[ Grunts ]

[ Chuckles ]

Wait. Let me do that again.

Hold on.

[ Grunts ]

Narrator: Despite igniting

the methane at its explosive

ratio, the manhole covers didn't

get air.

Manhole cover check one, two,

three... all still on.

I don't think an open system is

that energetic.

No.

Narrator: And the reason for

that lethargic blast?

Well, for that, it's over to the

hyneman.

Think of this like a gun.

If the back of the barrel of the

gun is closed, then the

exploding gunpowder goes this

way and pushes the bullet out

the end of the barrel.

However, if that breach is open,

the gas is gonna follow the path

of least resistance and escape

here.

And it's not gonna do

anything to the bullet.

Narrator: It's not looking

good for the open system.

But this myth doesn't rest

there.

I'm making a mess for

science.

Narrator: There's a whole lot

more manhole mayhem to come.

[ Laughs ]

Narrator: Next up is a fan

favorite with three times the

carnage.

All right, so, you guys are

familiar with bedliners, right?

Yeah, it's the stuff you

spray on your pickup-truck bed

to protect it.

Right.

Now, officially it's known to

stop scratches, dents, and rust.

But unofficially, people are

claiming that it is practically

indestructible.

I've read all sorts of crazy

stuff on the fan site... that

you can make a suit dog-proof,

you can make car crash-proof,

you can make a house

blast-proof.

I assume we're taking

most-outlandish and testing,

right?

Exactly.

Narrator: Bedliner... used to

line the beds of trucks and

protect against dings and

scratches.

But according to the fans,

that's not all.

Supposedly, it can defend

against damage in a host of

unconventional conditions.

We're gonna be working

with attack dogs, crashing cars

and exploding houses?

I think i love this myth

already.

Okay, well, before we get too

far, let's find out what the

bedliner's made of and how it

performs under normal

conditions.

Buzz kill.

Science.

Ready to find out about

bedliner?

I've got a few questions.

Narrator: So first, it's time

to bed down and find out how

just how this stuff works.

All right, mark, so, what

exactly is bedliner?

The bedliner material is a

two-component polyurethane

polyurea, elastomeric coating.

What is it normally used for?

You'll find these coatings do

very well where there's a high

abrasion, where typical paints

will not hold up.

So the applications are endless.

Yeah, but have you driven it

through any explosions been

attacked by dogs?

Not today, no.

[ Both laugh ]

Narrator: Right.

So bedliner is really only

designed to guard again dings

and scratches.

So now to get started on what

the fans claim it can do.

Number one... can bedliner make

your car crash-proof?

To find that out, they've got a

car.

So now to give it a very special

paint job.

We're going to spray half of

this car with bedliner and leave

the other half completely clean.

This car has not been in any

accidents, and there's not a

dent on it.

So we're starting from scratch.

Narrator: With aid of the

bedliner ninjas...

And the time-lapse camera, in no

time at all...

This is totally cured.

That's amazing.

All right, well, you get in

the unsafe side.

I'm driving.

All right.

[ Grunts ]

See? Abrasion-resistant.

Narrator: Abrasion-resistant

maybe, but to find out if it's

crash-proof...

[ Tires screech ]

it's time to, well, crash it.

[ Laughs ]

I don't like carpooling.

Can we not carpool anymore?

[ Grunts ]

Love when i get to drive.

We're going to simulate a minor

Fender-bender.

To do that we're going to back

our car in, treated and

untreated side, into this

barrier at 6 miles an hour.

We want to get minor damage and

compare the differences.

Narrator: Yep, and 6 miles

per hour still equates to a

5,000-joule impact.

Okay, this is

6-miles-per-hour rear-bumper

test.

Here we go.

Narrator: First, on the

untreated side....

Wow.

You got all of that one.

Ha!

Little more violent than i

expected.

Narrator: And then the

bedliner side.

Nice job, man.

I don't think I'll ever get

used to that.

[ Grunts ]

Narrator: Grant's no fan of

rear-enders, but it does seem

like the bedliner can take the

strain.

You know what?

I'm gonna have to say that

was a win for the bedliner.

Look at this, it's still intact.

Dude, that's crazy.

Narrator: The untreated

bumper is shattered, while the

bedliner is practically

untouched.

But can it survive a

6-mile-per-hour assault from the

front?

This is gonna be funny.

My god, what are you, blind?

[ Chuckles ]

Just kidding.

All right. That was a good hit.

Unh!

I'm okay.

Human crash-test dummy.

[ Grunts ]

Well, that was a solid hit,

and it looks like the bedliner

wins again.

Dude.

Look, we have cracking here

and here, but none on the

bedliner side.

That is totally amazing.

And that's some serious

damage right there.

Narrator: Serious damage, but

a collision of 6 miles per hour

is relatively tame compared to

what's coming up next.

On the other side of the

break, Tory putts pedal to the

metal.

Oh, my god, that was so fun.

Narrator: Later, it's Adam

and Jamie and the great drain

disaster.

That sewer's getting pretty

full of methane!

Narrator: In this drain

disaster, supposedly a sewer

explosion sends manhole covers

sky high.

However with their open-ended

system, that wasn't the case, as

the explosion took the path of

least resistance.

[ Grunts ]

Narrator: So for the next

test, the mythbusters are

closing the sewer, and that's

not as crazy as it sounds.

There are many places in

which a sewer can become a

closed system.

You can have a large pipe that

immediately makes a right-angle

turn into a small pipe.

Gases have a hard time going

around corners like that when

they're under pressure.

You can have a part of the sewer

above water with a bunch of the

sewer underwater.

All of a sudden, that becomes a

closed system.

Narrator: But will a methane

explosion in a closed sewer make

the difference and send the

manhole covers sky high?

In three, two, one.

Go.

[ Laughs ]

Awesome!

Go.

Narrator: Apparently, yes.

All the manhole covers went,

and it sounded cool, too.

Chrrrr! Ooh!

Narrator: The high-speed

referee proves that not only did

the lids flip, but they got

significant air.

Well, that worked pretty much

exactly as we hoped it would.

And here's what's going on in

there.

The reason those manhole covers

start to fly before the fire

even gets to them is that the

fire is an expanding gas.

And it is pushing air ahead of

it, kind of like a piston.

That piston is causing an

increase in pressure, which is

released by... poh!... The

manhole cover flying.

That's what we wanted to see.

Go.

Narrator: The closed-sewer

scenario may have achieved

manhole flight, but there's one

more parameter for the guys to

test inside their small-scale

drain.

I'm making a mess for

science.

This is the way it's supposed to

look.

[ Laughs ]

Narrator: That's right,

they're adding debris.

Because more junk might lead to

a bigger kerthunk.

Now, you might be looking at

this and thinking how is your

chamber full of Springs and coil

wire anything remotely

approaching a real-world

scenario?

How does that kind of blockage

occur in a real sewer?

Well, actually it does.

Real sewers have all sorts of

thing, like remnants of workmen

working on them, spools of wire,

ladders, equipment, things that

washed into the sewer, different

sizes of pipes in the sewer that

actually change and constrict

the air flow.

This kind of thing can

absolutely happen inside a

sewer.

Narrator: And with the

Springs providing 20% blockage,

will they put a spring in the

step of the manholes?

All right, here we go.

Drain disaster, small scale, 20%

obstruction, single-ignition

source.

And three, two, one.

Go.

Ho!

Oh! [ Laughs ]

Narrator: The scattering of

Springs accelerated the burn for

the most dramatic drain

explosion so far.

Wow.

Look at that, how fast it moves.

Oh!

[ Laughs ]

I've never seen anything like

that.

That is like a fireworks

show.

That was amazing.

[ Laughs ]

So, what's happening here?

Well, if you look at the

unblocked burn, you'll see that

the flame front is taking up

maybe in this case about a

quarter of a square foot.

It's moving out spherically from

the ignition source.

But looking at the blocked burn,

you'll see the flame starts to

wrinkle the minute it meets

these obstructions that we put

in the chamber.

That wrinkling creates a much

larger surface area, maybe

several square feet for all we

know.

But the end result is that the

flame front is able to

accelerate much more quickly

throughout the burn, and it

leaves the other one behind in

the same time.

Go.

Narrator: And that speedy

flame front creates the pressure

that propels the manhole covers

sky high.

Up over 36 inches, number

three, number two, and number

one.

And they're off the scale.

Freaking awesome.

Well, that's what we need to

do in the full size.

I think we have our testing

parameters.

[ Both chuckle ]

Narrator: Kari, Tory, and

Grant are on a collision course,

finding out if truck bedliner

can make your car crash-proof.

And so far, it's looking good.

Look, we have cracking here

and here, but none on the

bedliner side.

That is totally amazing.

All right.

We've already established that

bedliner works pretty well for

low-speed crashes.

But now it's time to put it

through the ultimate test... a

high-speed crash.

And for that Tory's gonna ram

it.

All right, Tory, whenever you're

ready!

Narrator: Tory's going to ram

both sides of the car at 25

miles per hour...

Or with an impact force of

50,000 joules.

[ Tires screeching ]

Nice.

Narrator: Remember, this is

for science, and Tory is not

enjoying himself at all.

[ Chuckles ]

Oh, my god.

That was so much fun.

Narrator: What's red and

white and dented all over?

Nice.

Narrator: After both impacts,

the difference between the

control and coated side is

negligible.

Check it out.

That's some pretty good

damage there.

It did look better on this

side.

Yeah. I mean, barely.

You know, this is still busted,

because it's definitely not

crash-proof.

All right. Yeah.

It helped a little bit but

didn't do it.

Good work, man.

Now, the fan site claims that

bedliner is indestructible.

You coat your car in it, it's

not only dent-resistant but it's

crash-proof.

I think we've proved them wrong

on that.

Anything small, abrasions,

little tiny dings... definitely

helps.

But you get anything more

severe, it's busted.

Narrator: Crash-proof is

busted.

But how about claim number two?

Can you make a d.I.Y. Dog-proof

suit with bedliner?

So, to see if bedliner can

actually make a fabric

bite-proof, we're gonna build

a dog biting robot.

We'll find out what fabric works

the best and once we've figured

all that out, then we'll bring

in the real dog.

Narrator: Ultimately, Tory

will face the jaws of fate.

But to make sure they're not

barking up the wrong tree, first

robo chomp will test if there's

any truth to the bedliner being

dog-tooth-proof.

Ahh.

This is an actual German

Shepherd skull.

Done a little bit of research

and found out that the German

Shepherd bites down with about

400 pounds of force.

So we're gonna take a

pneumatic cylinder, put it right

in this bit here, and that way

we can precisely control the

speed and the bite force until

it exactly matches a real dog.

Here we go.

Three, two, one.

[ Laughs ]

I'd call that successful.

Narrator: And for its next

meal, kari has found these.

We're gonna spray bedliner

on each one of these different

fabrics and see which one's

gonna be the best for a

dog-proof suit.

We have leather, denim, canvas,

and a quilted jacket.

Narrator: Those are the

contenders, and the winner will

be coated in bedliner and

hopefully make an attack dog

pause.

Now I'm gonna apply a

1/8-inch layer of bedliner, the

stuff that we have in the truck.

Feels like a carnival game!

Narrator: With one arm

sprayed and set and robo chomp

calibrated to a tech-scan rating

of 400 pounds, which fabric can

strong-arm its bite?

All right, sick him, boy.

Okay, control test, dog-bite

denim.

Here we go.

Three, two, one.

Oh!

You got a nice bite.

That's a bleeder.

One.

Ooh.

Narrator: Unsurprisingly, 400

pounds of bite force is more

than a match for the leather,

denim, canvas, and quilted

jackets.

Look at that.

Narrator: But how will the

bedliner fashion compare?

Okay, first up, denim.

Three, two, one.

Wow, that is strong.

Release.

Wow. Got it trained.

I don't think it penetrated.

Narrator: Well, it starts out

strong.

Doesn't look like there was

any penetration.

Cool.

This stuff's tough.

Leather jacket.

Narrator: And continues to

hold out.

It's not punching through?

No, not at all.

Okay, this is canvas arm with

bedliner.

Oh, my god, this is ridiculous!

It looks like it's working.

Bedliner quilted jacket.

Narrator: In fact, on every

jacket, the bedliner protects

against 400 pounds of robo

chomp.

Look at that.

It protected the arm, as well.

Not a scratch.

Wow. That's amazing.

Narrator: It looks like the

fans could be right about

bedliner being a cheaper

alternative to a dog-proof suit.

This coat is a little bit

more padded.

I feel a lot safer wearing this

if I'm gonna let the dog

attack me.

So what I'm gonna do now is

let them coat the rest of the

coat, and then we're gonna

let the dog out.

[ Dog growls, barks ]

Man, those high-speed shots

are some of the most beautiful

things we've ever gotten on a

small scale.

Where do we stand in going full

scale?

Well, the best-case scenario

is a closed system with lots of

blockages.

Also, surprisingly, it turns

out that nobody but nobody wants

to let us use a real sewer to

blow up.

Shocking.

Yeah.

I think we're gonna have to

make our own.

I'm thinking dig a nice big

trench, put down some real sewer

parts with real manhole covers,

and have a go at it.

Works for me.

Three, two, one.

Go.

Oh!

Narrator: So to upscale their

best-case-scenario sewer, the

guys will need to get down and

dirty in ione and build their

own.

Nice, wide-open space.

Perfect to blow up a sewer

in.

Now, of course, the first

prerequisite of building our own

sewer is a hole.

In order to get started, we're

going to need to find a hole.

Here's one.

Perfect!

Narrator: It's a conveniently

large hole for some

inconveniently large

construction.

Our sewer is gonna be 40 feet

long, and it's gonna made of

sections of something known as

box culvert.

They're precast concrete pieces

that will be 4 feet high and

6 feet wide.

The first thing we have to do is

put those in here and join them

together.

Narrator: Yep, and if you

thought the small-scale rig was

heavy-duty...

That piece of culvert behind

me weighs 32,000 pounds...

16 tons.

Altogether, this is the largest

construction project we've ever

undertaken for an experiment.

Narrator: It is, and luckily,

the team of heavy-lifters are on

hand to choreograph the culverts

into place.

I want to set it to music.

You guys are like ballet.

These things aren't just

decorations.

We saw in our small-scale

experiment that obstructions

like this dramatically speed up

the burn.

And so these may make the

difference between manhole

covers that jump up a little bit

or a lot.

Narrator: They're standing in

for real-life blockages like

sewer-servicing equipment and

garbage.

And based on the small scale,

they should accelerate the speed

of the burn.

You may be wondering why

we're going whole hog on this

thing rather than working

incrementally up to it.

Why start with the best-case

scenario?

Well, for two reasons.

We are spending a tremendous

amount of time and energy

building a full-size, full-scale

sewer, and we don't know that

maybe a mid-scale explosion

would render it useless for

further tests.

Given the number of unknowns, i

think it's safe to say that we

only have one shot at this.

The other reason we're going

full scale is because when you

scale things up from small scale

to large scale, things get

very, very complicated very

quickly, and given all of that,

we want to see what happens to

these manhole covers.

That's why we're going with the

best-case scenario.

[ Chuckles ]

Looking more like a real sewer

every minute.

Have you guys cleaned up?

It's a sewer down here.

Narrator: It's the best-case

scenario, but it's not an

unrealistic one.

Looks pretty good.

Narrator: Sewers are

naturally confined spaces.

Add to that what we know about

the instances of standing

water or pipe configuration, and

this closed system with

blockages is the most likely

scenario for a blast.

With the sewer stretcher

complete...

[ Laughs ]

It's almost done.

Narrator: It's time to

make the earth move.

We're gonna bury our sewer

under three feet of dirt, 'cause

while the dirt is actually an

important structural part of the

sewer, a sewer that's buried

underground, it will be a lot

less likely to blow apart than

one that's on the surface.

Narrator: Indeed.

Because the only things that are

supposed to blow are these.

And now what this whole

thing's all about... the manhole

cover.

[ Grunts ]

This is your basic cast-iron

manhole cover.

24 inches in diameter, an inch

and a quarter thick, and 103

pounds.

If this indeed is going to

become our projectile, we want

to make sure we see it.

So we're going to make it a

little more camera-friendly.

Narrator: The distinctive

manhole covers are manhandled

into place.

You know why manhole covers

are round, don't you?

It's the only shape that won't

fall through its own hole.

Yeah.

Narrator: And now to prep the

elements that will make their

sewer explosive.

Believe it or not, the

methane in this tank is enough

to create a blast equivalent to

120 pounds of high explosives.

Now, we're not gonna put all of

this in our sewer.

We're only gonna put 1/3 of it

or 100 cubic feet in there.

Bye.

[ Chuckles ]

But just to be safe, we're gonna

bury this in a pit nearby,

and we're gonna operate it

remotely with a solenoid.

Okay, it's done. We're wired.

Narrator: 100 cubic feet of

methane will fill their sewer to

the perfect ratio for a perfect

stoichiometric ratio for a big

boom.

We've optimized the design

of our full-scale experiment

based on everything we learned

in small scale.

We are going for the fastest

burn for deflagration possible.

Now, there is a small chance

that we could achieve a

detonation.

Let's lay some cable.

That means in order to be safe,

we have to remove all of our

systems... the gas release, the

gas monitoring, and the

ignition... almost a quarter of

a mile away.

Narrator: With that, their

spectacular sewer is ready for

what could be the most explosive

debut ever on "mythbusters."

[ Chuckles ]

They look beautiful!

This sewer is a replica of an

actual real-world sewer, except

that we've optimized it to give

it the best possible chance at

actually detonating a gas

instead of deflagrating it or

burning it.

Now, if it just burns, it'll be

fairly impressive, and the

manhole covers will probably go

fairly high.

But if it detonates, they're

really gonna go high.

And here's the thing.

If it detonates, this will be

the first incident that has ever

been recorded and documented of

a gas detonation occurring from

a natural source like a flame or

a spark.

That'll be something.

Coming up next on

"mythbusters," can bedliner make

a coat bite-proof?

Do not try what you're about

to see at home.

We're what you'd call

experts.

[ Horn honks ]

Narrator: Dogs... man's best

friend... loyal, cute, and

cuddly.

Well, most of the time.

All right, sick him, boy.

Narrator: Their bite may be

worse than their bark.

But can truck bedliner protect

you from the jaws of an angry

dog?

Looks like it's working.

Wow.

We're testing bedliner myths,

specifically that if you coat a

jacket in bedliner, you can make

it dog-bite-proof.

Now, so far, we created a

dog-bite rig that can bite down

with 400 pounds of force.

Next step is a real arm and a

real dog.

Dog's no problem.

Tory's gonna provide the arm.

Narrator: And German Shepherd

cliff is going to provide the

bite.

But before Tory gets into his

bedliner...

Okay, Dan, what do you think

is the best way to go about

this?

We'll start off with putting

Tory in the full bite suit and

letting cliff bite Tory.

Just so he can get the taste

of Tory.

And so Tory gets the feel of

cliff.

Does cliff like Italian?

He's never had any.

Narrator: That's about to

change, because for a starter,

Tory must don the familiar

dog-bite suit.

Whoa! Hey!

Narrator: And despite the

fact he's been here before...

I'm not nervous. I'm scared.

Narrator: Nobody likes

staring down a highly trained

attack dog.

Look, Tory, he's salivating.

[ Dog growls ]

This isn't gonna be good.

Hey, you. Stop.

[ Speaking indistinctly ]

[ Dog barks ]

Good boy.

Good dog. Good boy.

Narrator: As expected, the

heavy-duty nylon of the bite

suit protects Tory from cliff's

bite.

But cliff doesn't seem to know

that.

Platz!

Aus.

Platz.

He didn't let go that fast.

Apparently he likes the

Italian.

Holy crap.

[ Dog snarls ]

I'm nervous.

I think it's gonna hurt.

Did you see how long it took him

to get it off me?

Does anybody else feel bad about

this, or is it just me?

Narrator: Although the bench

test may have proven the

bedliner successful...

Doesn't look like there was

any penetration.

Narrator: Robo chomp is a far

cry from an angry attack dog.

Good dog. Good boy.

Look at him.

He's looking pissed.

He's like, "you want to go

again?"

Not really. I don't.

Don't know why.

[ Dog barking ]

All right, it's the moment of

truth.

Narrator: With the control

complete, it's time for Tory to

make his bedliner debut.

Wow.

That is the height of fashion,

my man.

Well, thank you, friend.

Does it close up?

Uh, well, the problem is...

i think i put on a little

weight with these pants.

Bring out the dog.

Let's get this over with.

[ Whistles ]

Grab the arm.

Narrator: With Tory squeezed

into the jacket, it's the moment

of truth.

This seems like the opposite

of a good idea.

I hope this suit works.

Get that bedliner.

Get the bedliner.

Okay, this is bedliner

jacket.

Is it dog-bite-proof or not?

[ Dog barking ]

Fass!

Good boy. Fass! Yeah!

Fass! Fass! Fass! Fass!

[ Laughs ]

Whoo!

It stopped it.

That was incredible.

Aus! Platz!

Narrator: Amazingly, it's

just seconds before cliff

realizes that he won't get his

man.

The bedliner is too tough.

That was incredible.

It stopped the dog from biting

through the jacket.

Oh, my god, i never want to get

bit by one of those for real.

We've had dogs attack us wearing

these suits but these are rated

for dog attacks.

They're designed so that you

don't get hurt.

However, this has never been

rated so i had no idea whether

or not the dog's teeth were

gonna tear through this or

not.

It worked.

It stopped the dog attack.

We have a dog-bite-proof

suit.

I call this one confirmed.

Confirmed.

What's worse, the bark or the

bite?

The bite.

Narrator: Down at ione,

California, the mythbusters'

great drain disaster is about to

go off.

Here's how this is gonna

work.

We will be activating this

experiment from 1,000 feet away

in the safety of this steel

bunker behind bullet-resistant

glass.

When i click this switch...

It'll open this valve and

allow the methane to flow...

Into our homemade sewer

buried underground.

When the stoichiometry or the

mixture between gas and air has

reached the ideal relationship

for an explosion...

I'll hit this switch,

creating a spark, which will

ignite the gas...

Hopefully sending these three

manhole covers flying sky high.

That's the theory.

Narrator: That's the theory

because if the 103-pound

manholes don't fly sky high, the

myth is busted.

What we need to see for this

myth to be true is pretty

straightforward.

We need to see some type of

shock wave or explosion that

does not destroy the sewer and

yet launches the manhole covers.

And I'm not talking like a

boonk-boonk.

I'm not even talking like a

boonk-whew-whew-boonk.

I'm talking launches them.

Narrator: Well, with the fire

department on standby, there's

only one way to find out if

those manholes will fly.

You ready?

I'm gonna start the flow of gas.

Let her rip.

Narrator: It will take 100

cubic feet of methane to get

their sewer to the optimum

explosive ratio.

21 cubic feet.

About 2%.

1/5 of the way there.

Narrator: It's that familiar

"mythbusters" waiting game.

That sewer's getting pretty

full of methane!

Narrator: Small scale proved

that the perfect stoichiometric

ratio sent manholes flying.

However, will the full-scale

equivalent... 100 cubic feet of

methane... prove just as

effective?

Shall we do it?

I think it's time.

All right. Call it.

All right.

Real-world sewer explosion,

best-case scenario, sparking in

three, two, one.

Whoa!

Look at that!

That had to be 100 feet.

That was insane!

[ Laughs ]

That exceeded my wildest

expectations.

That was significant.

Narrator: Significant is

right.

The manholes turned missile,

rocketing 150 feet and only

returning to earth after a hang

time of six seconds.

Go take a look.

All right.

Narrator: And closer

inspection of their sewer has

the guys astonished at the force

of the explosion.

There's two.

There's three.

And number one seems to have

traveled the farthest.

That is one hell of a blast.

[ Chuckles ]

I think the whole roof of the

sewer came up.

Well, as I'm walking on it, i

can feel that it feels soft.

Do you feel that?

That's what I'm saying.

All this dirt kind of came up in

the air a foot or something.

We should check our high-speed.

That was awesome.

Narrator: Yep, and from the

safety of solid ground, the

high-speed shows that the

deflagration of the sewer sent

earth and manholes flying.

There they go.

Wow!

It's perfect.

They look like flying saucers

taking off.

Look at number showing itself

to the camera.

[ Laughs ]

That is insane.

That might be one of my favorite

high-speed shots we've ever

gotten.

That's gorgeous.

Narrator: Gorgeous and also

very revealing.

Now, seeing fire coming out

of that manhole cover and not

the others is telling us that

this is not a detonation.

If it was a detonation, it'd all

be simultaneous.

We're not seeing that, so this

is a burn.

Narrator: Yep, but a burn big

and fast enough to bring the

manhole mayhem to a close.

Well, if there's one thing

everyone knows they can expect

from a sewer explosion it's that

number two is gonna fly into the

air, and that's what happened.

I'd say mission accomplished.

You know, it kind of makes

you wonder, could you get a jet

of fire like that coming out of

the toilet when you're sitting

on it if something like that

happened?

Man, that was awesome.

We got a super-fast burn.

We got internal pressures in the

sewer of over 100 pounds per

square inch, and our manhole

covers flew 150 feet in the air.

Yeah, and that wasn't even a

detonation.

Can you imagine what'd happen if

the flame front and the

shock wave got lined up?

Everything happens at once, and

who knows how high they'd go?

Still, we have plenty of

information to fully call this

myth.

Yep. It's confirmed.

Totally confirmed.

Sometimes the truth is far more

spectacular than fiction.

Narrator: Next, kari, Tory,

and Grant have a blast.

I like our c-4 remodeling.

Narrator: But can bedliner

save buster?

Final experiment for bedliner

bedlam... the bomb.

If you coat your house in

bedliner, you can make it

blast-proof.

All right, here's what I'm

thinking.

Four walls total.

Two cinder-block walls, one

coated and one not, and two

standard wood-frame walls, one

one coated, one not.

Then we detonate an

explosive, see how the myth

stands.

All right.

And then we'll see how strong

this stuff really is.

Narrator: And quick as a

flash they've knocked up those

four walls for a test.

So, we have two sets of

walls... wooden ones and

cinder-block ones.

And we're gonna see how well the

bedliner does against an

explosion.

A lot of people ask me, "do you

ever get tired of blowing stuff

up?"

And i tell them, no, i don't.

Narrator: It'll be a blast

times four.

But that's not good news for

buster.

So, we've placed buster

right in the

middle of our wood-frame house.

He's got no instrumentation

inside of him.

It's a visual test.

We want to see if the walls fall

in on him.

Now, this side of the wall,

I'm setting up the blast.

C-4 is exactly 5 feet away from

the center of the wall.

When this thing explodes, it's

gonna be putting out a blast

load of 95 p.S.I.

Let's see how the wood wall

handles it.

Okay, this is control test

for bedliner.

Here we go.

Three, two, one.

Whoa!

Blew a hole in that wall.

Oh, yeah.

[ Laughs ]

I can see buster!

[ Laughter ]

He's all blackened.

Cajun buster!

Narrator: Unsurprisingly, the

code-compliant wooden wall

between buster and the c-4

failed.

Looks like we just put a new

door in.

I like our c-4 remodeling.

Now, if this bedliner has any

hope of working at all, what'

it's got to do is contain most

if not all of this and keep it

from hitting buster.

My prediction... i don't think

so.

Narrator: Well, to find out,

it's relocation, relocation, as

buster is moved to an identical

wooden home...

Good luck, buster.

You're gonna need it.

Narrator: All except the

coating of bedliner.

Now for the bedliner house.

Same amount of c-4, same

distance.

[ Siren wails ]

All right, this is wall wood,

wood bedliner versus c-4.

Do it.

In three, two, one.

And the smoke clears and...

What?!

Still standing!

Wow!

The wall is still together.

But we've got to check the

inside.

Let's go look.

Let's go look!

Ah!

It worked, baby!

It stopped the shock wave

from breaking through the wall.

That's incredible.

This is in remarkably good

shape.

All right, well, it's

blast-proof from the outside.

Let's check the inside.

[ Laughs ]

Oh!

I would have to say this is

totally blast-proof.

Narrator: Amazingly, the

coated wooden walls are indeed

bomb-proof.

But can bedliner hold the c-4

wolf away for the cinder blocks?

Now we are moving on to the

cinder-block wall, but we are

gonna double the amount of c-4.

The reason is because the amount

that we used on wood walls would

not do any damage to the

cinder-block wall.

All in all...

It's just another brick in the

wall.

And in doing so, we are also

increasing the amount of blast

load from 95 p.S.I. To

1,400 p.S.I.

We're gonna set off c-4 in

front of both walls and see what

happens.

Narrator: So first, to find

out what double the c-4 does to

their cinder-block control.

In three, two, one.

Whoa!

Yeah!

I see a hole.

Yep.

[ Chuckles ]

Wow!

Wow, it blew the whole back

out.

It bowed just like the wood

wall, but pushed all the bricks

out of the mortar.

And i would have to say

buster probably didn't survive

this blast.

All right, well, let's see

what the bedliner does.

Okay.

That was pretty impressive.

Narrator: For the ultimate

test of bedliner, buster has his

back to the reinforced wall.

But will it be enough to protect

him from a c-4 blast?

This is bedliner on a

cinder-block wall in three, two,

one.

[ Laughs ]

Wow!

I see smoke rising, and...

Left a big, black mark, but i

don't think it did any damage to

it.

I don't see a hole.

I don't see any holes.

Narrator: From the front,

it's looking good for

blast-proof bedliner.

Guys, it's looking really

good from this side.

Yeah, there's hardly any

damage.

It's just dirt.

Well, let's look at the other

side.

What?!

Oh!

Nice!

It worked!

Buster survived!

So, bedliner is blast-proof.

Totally blast-proof.

This one's confirmed.

So, as it turns out, bedliner

has amazing blast-proofing

qualities.

We sprayed it on our wood wall

here.

It kept the wall together and

kept it from showering buster

from debris.

Now, here with our cinder-block

wall, it totally devastated the

back of the wall, crumbled

everything... debris everywhere.

And here on our treated

cinder-block wall, not a scratch

on it.

Bedliner as a blast-proofing

agent... confirmed.

That's incredible, man!

Wow.

We've got a new application for

bedliner, huh?

That's awesome stuff.

What else can we do with it?

Let's see if we can make

stuff bulletproof.

What about shark-proof?

What about bear-proof?

Want to know why we did what

we did and why we didn't do what

we didn't?

Go to discovery. Com/

mythbustersaftershow.