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[SOUND] Before looking closer at torch
handles, we need to explain a few terms

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and understand some of the hazards
associated with oxy-fuel equipment.

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The terms are reverse flow, flashback,

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backfire, and sustained backfire.

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Reverse flow is when either the oxygen
enters the fuel gas side of the system,

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or the fuel gas enters
the oxygen side of the system.

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This occurs when there's
a restriction of one of the gases or

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an imbalance of pressure.

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This can be caused by a clogged or
blocked tip, or

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allowing one of your
cylinders to run out of gas.

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If a reverse flow condition exists,
a flashback can occur.

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Flashback is the retun of a flame
through the torch into the hose and

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even into the regulator.

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It could potentially reach the cylinder.

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This condition could cause an explosion
anywhere within the system.

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Flashback arrestors are designed to
prevent the flame from traveling

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beyond the point of the arrester.

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Flashback arrestors contain
a sintered filter which prevents

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a flame from passing
through the filter element.

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Backfire is the return of
a flame back into the torch,

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which produces a popping sound.

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The flame will either extinguish or
reignite at the tip.

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This is normally the result of
accidentally bumping the tip against

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the workpiece, operating the tip
too close to the workpiece, or

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allowing the tip to become overheated.

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The last event is a sustained backfire.

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This is when a backfire occurs and
continues burning in the torch.

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This condition may be accompanied
by a popping sound followed by

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a continuous whistling or hissing sound.

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Some of the causes for this are improperly
maintained equipment, overheating of

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the equipment, or improper pressure
settings for the equipment being used.

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[SOUND]
>> This is a typical Victor handle.

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On most of our popular handles,

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you'll notice there'll be a built-in flash
arrester and a built-in check valve.

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One of the misconceptions in our industry
is a check valve will stop a fire,

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that's not true.

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What a check valve is designed to do is
to stop the gas from getting on the wrong

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side of the torch.

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A flash arrester is
designed to stop a fire.

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A flash arrester will stop the fire
from advancing further up the system.

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>> And if your torch doesn't have
a check valve or flashback arrestor it,

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we strongly recommend that you
install them before operating.

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>> And if you do, you may have heard
it there, you put them at the torch or

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the regulator or both places.

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And if you decide to put them at
the regulator and at the torch,

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make sure you check with
the manufacturer's data sheet to make sure

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it will not restrict flow to your torch.

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[SOUND]
>> To reiterate what Tim said,

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the best rule is to have safety devices
as close to operation as possible.

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This means incorporating check valves and
flashback arrestors into the torch.

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[SOUND]
>> This is a typical Victor handle.

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It's designed to deliver the gas
in a safe manner to the mixer.

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One of the big misconceptions in our
industry is that the mixer is in

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the handle, and that's not true.

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Each individual component
has its own mixer.

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Today, we're gonna talk about heating and
cutting,

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the most popular uses of the torch.

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>> And this is a heating attachment.

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A heating attachment can be used for
heat treating, priming,

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descaling, straightening,
many other options.

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Before you use this heating attachment,

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you need to be sure to check the cone
end of your attachment has two O-rings.

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And on those O-rings, you have to make
sure they're neither missing nor damaged.

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That could lead to a leak that
might lead to an accident.

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So be sure to repair them or
replace them before using.

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>> And
here's the typical cutting attachment.

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Do the same inspection on the cone end,
as Ken just advised.

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In addition, we also wanna make sure that
we check the seating end for the tip, no

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dents or scratches in here, because this
will eventually be a metal-to-metal seal.

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Before attaching the cutting
attachment to the torch,

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we wanna inspect the exceeding area of the
torch handle and also the thread assembly.

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Then you wanna attach them,
hand-tighten only.

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At this point, if we use a wrench on it,
you're gonna damage the O-rings.

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So we're gonna hand-tighten this on there,
all right?

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After you get that on,
one of the things we wanna do,

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we're now gonna take and open this
preheat valve all the way on the handle.

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If we don't open it all the way, you'll
get a restriction in your cutting oxygen.

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This will now be your preheat
adjustment for your oxygen.

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Now, we'll take a look at the tip.

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You wanna make sure you can inspect the
tip on the end, make sure preheat holes

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are free of debris, and
the cutting hole itself is free of debris.

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You also wanna check the seating end.

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This is going to be a metal-to-metal seal,
so

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we gotta make sure there's no scratches or
dents in the system.

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Now, unlike the cutting
attachment to the handle,

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we'll now tighten this on with a wrench,
and

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you need to tighten it securely
because of the metal-to-metal seal.

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We'll then take a look at
the cutting lever itself,

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make sure it moves freely, there's no
resistance, and we're ready to go.

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[SOUND]
>> Your torch inspection checklist should

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include the following, inspect valves,
fittings, and seating areas for damage.

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Ensure both O-rings are intact and
in place.

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Ensure the torch is free from oil and
grease.

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Make sure the tips are free from slag or
obstruction.

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[SOUND]
>> Manufacturers such as Victor provide

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tip charts, and they help you to
determine the proper flow settings.

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Note that alternate fuels
use different tips,

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and they require different
pressure settings.

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>> The thickness of your plate would
determine what tip you use, and

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in turn, the tip will determine
what pressures I need.

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Take, for example, this is a number
one acetylene cutting tip, and

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I'll set my pressures at 25 PSA on
the oxygen and about 5 on the fuel gas.

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If I would change thickness and, say, go
to an inch plate, I'd also have to change

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the tip to a number two and my pressures
would be different at the regulator.

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So I'd refer to the tip charts
that Ken had mentioned earlier.

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[SOUND]
>> If you don't have tip charts,

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ask your equipment supplier to
help with recommended settings.

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Also remember the one-seventh rule for
using acetylene.

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Make sure you have adequate capacity
from the acetylene cylinder to support

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the acetylene consumption
of the tip you're using.

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After connecting the attachments and tips,

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you need to check the entire system for
leaks.

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The steps to perform a leak
test are as follows.

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First, ensure that the adjusting
mechanism is completely backed out.

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Open the gas slowly until the high
pressure gauge reading stabilizes,

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then shut off the cylinder valve.

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Monitor the gauge for any pressure drop,

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which would indicate a leak of
the high pressure side of the system.

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If no leak is evident,
open the cylinder valve and

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adjust the oxygen regulator
to deliver 20 PSI.

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Repeat the process with the fuel
gas valve and regulator, but

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be sure to adjust the fuel gas
regulator to deliver only 10 PSI.

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Close both the oxygen and
fuel cylinder valves.

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Turn the adjusting screw or
knob counter clockwise one-half turn.

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Observe the gages on both regulators for
a few minutes.

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If the gauge readings do not change,
then the system is leak tight.

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Open the cylinder valves again.

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Any movement of the needles
indicates a possible leak.

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If you observe a leak, stop.

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Do not use leaking equipment.

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Check all the connections.

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If you can't find the leak,

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have the equipment inspected
by a qualified technician.

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Just like we purged a cylinder valve and
hoses earlier, we need to purge the torch.

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In this case, it's to eliminate the
possibility of gases mixing prematurely,

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which could lead to a flashback or worse.

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>> To purge the torch,
the first thing you wanna do is

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open the oxygen valve on
the torch handle all the way.

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And with a cutting attachment,
also open the preheat oxygen valve and

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depress the cutting lever for
three to five seconds.

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We'll shut that off and we'll repeat
the process for the fuel side.

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We're gonna open the fuel side for three
to five seconds and then shut it off.

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>> And Ken, this is a good time to recheck
your regulators to make sure you maintain

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the same pressure.

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[SOUND]