I've seen a few of the suppliers that sell torches for glassblowing also
sell oxygen concentrators so you can run the torches without having to buy
oxygen in tanks. I'm wondering if this would be beneficial to metalworkers
that do a lot of torch work.

http://www.sundanceglass.com/oxygen-concentrator.htm

They have 7PSI 5LPM for $275. This may be OK for oxy/acetylene welding but
not enough pressure (or volume) for cutting. So what about adapting an oil
free compressor and a tank to give you enough pressure and volume for
cutting torch operation. Seems this price is getting competitive with the
price of tank and contents, or at least by the time you have to get a couple
of refills.

It would be nice to find a high pressure compressor compatible with oxygen
to fill my own tanks. I priced a small 1/2HP oxygen compressor that went to
2200PSI for tank filling, the price was almost $5000 for the compressor.
Anyone know of an affordable safe way to boost ~5PSI from an oxygen
concentrator to high enough pressure to be useful for a cutting torch or
even to fill an oxygen tank?

Also, is it OK to run an oxy/acetylene torch on oxy/propane? I know they
have different tips for propane for the cutting torch but not sure about the
welding torch. From my understanding I know you need Grade T hose instead
of the grade R, but not sure if there is any difference in the brazing torch
tips.

RogerN

RogerN wrote:


I've seen a few of the suppliers that sell torches for glassblowing also
sell oxygen concentrators so you can run the torches without having to buy
oxygen in tanks. I'm wondering if this would be beneficial to
metalworkers that do a lot of torch work.

http://www.sundanceglass.com/oxygen-concentrator.htm

They have 7PSI 5LPM for $275. This may be OK for oxy/acetylene welding
but
not enough pressure (or volume) for cutting. So what about adapting an
oil free compressor and a tank to give you enough pressure and volume for
cutting torch operation. Seems this price is getting competitive with the
price of tank and contents, or at least by the time you have to get a
couple of refills.
Pure Oxygen is extremely dangerous. Only certain metals and plastics
are compatible with it. For instance, a fingerprint left inside an
oxygen system is enough to cause a fire that will set the metal lines
on fire.

It would be nice to find a high pressure compressor compatible with oxygen
to fill my own tanks. I priced a small 1/2HP oxygen compressor that went
to 2200PSI for tank filling, the price was almost $5000 for the
compressor. Anyone know of an affordable safe way to boost ~5PSI from an
oxygen concentrator to high enough pressure to be useful for a cutting
torch or even to fill an oxygen tank?

You don't need anywhere near 2200 PSI for a cutting torch, so that may
help keep the cost down. Partly, you are paying for liability insurance,
as anywhere pure Oxygen is used, there WILL be an occasional incident.

Jon

Jon Elson wrote:
RogerN wrote:


I've seen a few of the suppliers that sell torches for glassblowing also
sell oxygen concentrators so you can run the torches without having to buy
oxygen in tanks. I'm wondering if this would be beneficial to
metalworkers that do a lot of torch work.

http://www.sundanceglass.com/oxygen-concentrator.htm

They have 7PSI 5LPM for $275. This may be OK for oxy/acetylene welding
but
not enough pressure (or volume) for cutting. So what about adapting an
oil free compressor and a tank to give you enough pressure and volume for
cutting torch operation. Seems this price is getting competitive with the
price of tank and contents, or at least by the time you have to get a
couple of refills.
Pure Oxygen is extremely dangerous. Only certain metals and plastics
are compatible with it. For instance, a fingerprint left inside an
oxygen system is enough to cause a fire that will set the metal lines
on fire.

I like how they learned all these weird dangers the hard way. Somebody
posted some story here about some nasty flourinated chemical that once set
a concrete containment dike on fire- as in the concrete was burning.

On Sep 9, 9:57*pm, Jon Elson wrote:
RogerN wrote:

I've seen a few of the suppliers that sell torches for glassblowing also
sell oxygen concentrators so you can run the torches without having to buy
oxygen in tanks. *I'm wondering if this would be beneficial to
metalworkers that do a lot of torch work.

http://www.sundanceglass.com/oxygen-concentrator.htm

They have 7PSI 5LPM for $275. *This may be OK for oxy/acetylene welding
but
not enough pressure (or volume) for cutting. *So what about adapting an
oil free compressor and a tank to give you enough pressure and volume for
cutting torch operation. *Seems this price is getting competitive with the
price of tank and contents, or at least by the time you have to get a
couple of refills.

Pure Oxygen is extremely dangerous. *Only certain metals and plastics
are compatible with it. *For instance, a fingerprint left inside an
oxygen system is enough to cause a fire that will set the metal lines
on fire.

It would be nice to find a high pressure compressor compatible with oxygen
to fill my own tanks. *I priced a small 1/2HP oxygen compressor that went
to 2200PSI for tank filling, the price was almost $5000 for the
compressor. Anyone know of an affordable safe way to boost ~5PSI from an
oxygen concentrator to high enough pressure to be useful for a cutting
torch or even to fill an oxygen tank?

You don't need anywhere near 2200 PSI for a cutting torch, so that may
help keep the cost down. *Partly, you are paying for liability insurance,
as anywhere pure Oxygen is used, there WILL be an occasional incident.

Jon- Hide quoted text -

- Show quoted text -

Well said Jon.

TMT

RogerN wrote:

I've seen a few of the suppliers that sell torches for glassblowing also
sell oxygen concentrators so you can run the torches without having to buy
oxygen in tanks. I'm wondering if this would be beneficial to metalworkers
that do a lot of torch work.

http://www.sundanceglass.com/oxygen-concentrator.htm

They have 7PSI 5LPM for $275. This may be OK for oxy/acetylene welding but
not enough pressure (or volume) for cutting. So what about adapting an oil
free compressor and a tank to give you enough pressure and volume for
cutting torch operation. Seems this price is getting competitive with the
price of tank and contents, or at least by the time you have to get a couple
of refills.

It would be nice to find a high pressure compressor compatible with oxygen
to fill my own tanks. I priced a small 1/2HP oxygen compressor that went to
2200PSI for tank filling, the price was almost $5000 for the compressor.
Anyone know of an affordable safe way to boost ~5PSI from an oxygen
concentrator to high enough pressure to be useful for a cutting torch or
even to fill an oxygen tank?

Also, is it OK to run an oxy/acetylene torch on oxy/propane? I know they
have different tips for propane for the cutting torch but not sure about the
welding torch. From my understanding I know you need Grade T hose instead
of the grade R, but not sure if there is any difference in the brazing torch
tips.

RogerN

Around here at least, it's very common to see a welder's truck with a
big ~300L liquid Oxygen Dewar next to a few acetylene cylinders. Those
Dewars will output at about 35PSI and hold a huge volume of gas. Last I
checked the lease on one was only like $200/yr.

On 9/10/2012 5:50, RogerN wrote: I've seen a few of the suppliers that
sell torches for glassblowing also
sell oxygen concentrators so you can run the torches without having
to buy
oxygen in tanks. I'm wondering if this would be beneficial to
metalworkers
that do a lot of torch work.

http://www.sundanceglass.com/oxygen-concentrator.htm

They have 7PSI 5LPM for $275. This may be OK for oxy/acetylene
welding but
not enough pressure (or volume) for cutting. So what about adapting
an oil
free compressor and a tank to give you enough pressure and volume for
cutting torch operation. Seems this price is getting competitive
with the
price of tank and contents, or at least by the time you have to get a
couple
of refills.

Normal air compressor at 10bar has already 2.1bar of oxygen in
the tank.. It is just the partial pressure that matters.

It would be nice to find a high pressure compressor compatible with
oxygen
to fill my own tanks. I priced a small 1/2HP oxygen compressor that
went to
2200PSI for tank filling, the price was almost $5000 for the compressor.
Anyone know of an affordable safe way to boost ~5PSI from an oxygen
concentrator to high enough pressure to be useful for a cutting torch or
even to fill an oxygen tank?

Pressure booster is the name.. Pneumatic version uses a big
area cylinder to push a small-diameter high-pressure cylinder..
Push-pull usually so the big one has two smaller cylinders
at both sides with the stem output from both sides. Then
just some one-way valves and an oscillator with the big
cylinder, and there you go.. Available at ebay sometimes used.

Used diving bottle filling compressors would be another way to go.
If they compress air to 200bar, they handle oxygen partial pressure
of 42bar at output. It is the same whether there is only 42bar oxygen
or air at 200bar.


Propably the cheapest and metalworking way is to build it
yourself from a few pneumatic cylinders.. If you keep the
oxygen pressure low (like less than 40bar), there is IMHO no
need for any special cleanliness. Use compressed air for
operating the driver cylinders, and oxygen enriched air from
the concentrator for the compressing cylinders. The cylinder
stems could be used for triggering limit switches, operating
the oscillator action. Really rather simple. One-way valves
could be swagelok or such quite cheap components.

Kristian Ukkonen.

On Sun, 09 Sep 2012 21:57:01 -0500, Jon Elson wrote:

RogerN wrote:


I've seen a few of the suppliers that sell torches for glassblowing
also sell oxygen concentrators so you can run the torches without
having to buy oxygen in tanks. I'm wondering if this would be
beneficial to metalworkers that do a lot of torch work.

http://www.sundanceglass.com/oxygen-concentrator.htm

They have 7PSI 5LPM for $275. This may be OK for oxy/acetylene welding
but
not enough pressure (or volume) for cutting. So what about adapting an
oil free compressor and a tank to give you enough pressure and volume
for cutting torch operation. Seems this price is getting competitive
with the price of tank and contents, or at least by the time you have
to get a couple of refills.
Pure Oxygen is extremely dangerous. Only certain metals and plastics
are compatible with it. For instance, a fingerprint left inside an
oxygen system is enough to cause a fire that will set the metal lines on
fire.

I thought it was pure oxygen at high pressure or in liquid form that was
so very dangerous -- does this hold for oxygen at 40 psi?

--
My liberal friends think I'm a conservative kook.
My conservative friends think I'm a liberal kook.
Why am I not happy that they have found common ground?

Tim Wescott, Communications, Control, Circuits & Software
http://www.wescottdesign.com

On 9/10/2012 19:49, Tim Wescott wrote: On Sun, 09 Sep 2012 21:57:01
-0500, Jon Elson wrote:
RogerN wrote:
I've seen a few of the suppliers that sell torches for glassblowing
also sell oxygen concentrators so you can run the torches without
having to buy oxygen in tanks. I'm wondering if this would be
beneficial to metalworkers that do a lot of torch work.
http://www.sundanceglass.com/oxygen-concentrator.htm
They have 7PSI 5LPM for $275. This may be OK for oxy/acetylene welding
but
not enough pressure (or volume) for cutting. So what about adapting an
oil free compressor and a tank to give you enough pressure and volume
for cutting torch operation. Seems this price is getting competitive
with the price of tank and contents, or at least by the time you have
to get a couple of refills.
Pure Oxygen is extremely dangerous. Only certain metals and plastics
are compatible with it. For instance, a fingerprint left inside an
oxygen system is enough to cause a fire that will set the metal lines on
fire.
I thought it was pure oxygen at high pressure or in liquid form that was
so very dangerous -- does this hold for oxygen at 40 psi?

Normal compressor has oxygen at about 2.1bar (30psi) if
tank is at 10bar.. 21% of air is oxygen.. Compressor with
higher tank pressure has higher oxygen partial pressure.

Normal "instrument air" (synthetic air) is 21% oxygen at 200bar
in a bottle.. Nothing special required yet at partial pressure of
oxygen at 42bar. Just normal nitrogen pressure reducer etc..
This is all stated by the "safety sheet" of the product by
gas company.

So my opinion is not to worry at less than 42bar of oxygen.

Kristian Ukkonen.

"Tim Wescott" wrote...

I thought it was pure oxygen at high pressure or in liquid form that
was
so very dangerous -- does this hold for oxygen at 40 psi?

http://en.wikipedia.org/wiki/Apollo_1

jsw

On Mon, 10 Sep 2012 14:20:58 -0400, Jim Wilkins wrote:

"Tim Wescott" wrote...

I thought it was pure oxygen at high pressure or in liquid form that
was
so very dangerous -- does this hold for oxygen at 40 psi?

http://en.wikipedia.org/wiki/Apollo_1

jsw

D'oh.

--
My liberal friends think I'm a conservative kook.
My conservative friends think I'm a liberal kook.
Why am I not happy that they have found common ground?

Tim Wescott, Communications, Control, Circuits & Software
http://www.wescottdesign.com

I thought it was pure oxygen at high pressure or in liquid form that was
so very dangerous -- does this hold for oxygen at 40 psi?

I would not drive or ride in a truck with a LOX tank mounted behind
me. Think of traffic accidents with it splashing around. You could be
the feature picture at every news cast in the country. It is better to
keep away from liquid gas transporters on the freeway too.

Tim Wescott wrote:


I thought it was pure oxygen at high pressure or in liquid form that was
so very dangerous -- does this hold for oxygen at 40 psi?

LOX is the worst, as it is insanely concentrated. But, even pure
O2 at STP is pretty dangerous stuff. They've had some horrible fires
in operating rooms where pure oxygen the patient was breathing was allowed
to spill on surgical drapes and such and got ignited possibly by a
static discharge. You can't put that kind of fire out with a fire
extinguisher until all the oxygen is used up. The Air Force did some
testing just after WW-II to make sure pilots could operate long-term
while breathing pure O2. They had a chamber with a bunch of guys living in
pure O2, and had a fire when a guy changed a burned-out light bulb.
When the porcelain light socket started dripping flaming porcelain onto an
asbestos fire blanket and the asbestos caught on fire, they popped the door
open and escaped.

The Apollo 11 fire is another case, of course, and they couldn't get out
in time.

Jon

Kristian Ukkonen wrote:



Normal air compressor at 10bar has already 2.1bar of oxygen in
the tank.. It is just the partial pressure that matters.

Sorry, but I don't believe this! I just don't believe that
air at such a pressure that the oxygen partial pressure equals
some pure oxygen pressure has the same flammability problem.
You can put compressed air in a bottle and plumb it up with any
regulator and lines you want, and not worry about cleanliness,
lubricants, etc. For oxygen, you need to be VERY careful about
materials, lubes, regulator diaphragms, etc.

Jon

On Mon, 10 Sep 2012 20:51:05 +0300, Kristian Ukkonen
wrote:

On 9/10/2012 19:49, Tim Wescott wrote: On Sun, 09 Sep 2012 21:57:01
-0500, Jon Elson wrote:
RogerN wrote:
I've seen a few of the suppliers that sell torches for glassblowing
also sell oxygen concentrators so you can run the torches without
having to buy oxygen in tanks. I'm wondering if this would be
beneficial to metalworkers that do a lot of torch work.
http://www.sundanceglass.com/oxygen-concentrator.htm
They have 7PSI 5LPM for $275. This may be OK for oxy/acetylene welding
but
not enough pressure (or volume) for cutting. So what about adapting an
oil free compressor and a tank to give you enough pressure and volume
for cutting torch operation. Seems this price is getting competitive
with the price of tank and contents, or at least by the time you have
to get a couple of refills.
Pure Oxygen is extremely dangerous. Only certain metals and plastics
are compatible with it. For instance, a fingerprint left inside an
oxygen system is enough to cause a fire that will set the metal lines on
fire.
I thought it was pure oxygen at high pressure or in liquid form that was
so very dangerous -- does this hold for oxygen at 40 psi?

Normal compressor has oxygen at about 2.1bar (30psi) if
tank is at 10bar.. 21% of air is oxygen.. Compressor with
higher tank pressure has higher oxygen partial pressure.

No, normal compressor at 10 bar tank pressure has oxygen (in the air)
at 10 bar. There is no separation in the tank, at least not that I've
ever heard of. Why would the hydrogen (and other gases) compress at a
higher pressure? That's daft, man!


Normal "instrument air" (synthetic air) is 21% oxygen at 200bar
in a bottle.. Nothing special required yet at partial pressure of
oxygen at 42bar. Just normal nitrogen pressure reducer etc..
This is all stated by the "safety sheet" of the product by
gas company.

Cite, please?


So my opinion is not to worry at less than 42bar of oxygen.

Good.


--
Courage and perseverance have a magical talisman, before
which difficulties disappear and obstacles vanish into air.
-- John Quincy Adams

"Larry Jaques" wrote in message
Cite, please?

http://en.wikipedia.org/wiki/Partial_pressure

jsw

In article ,
says...

Tim Wescott wrote:


I thought it was pure oxygen at high pressure or in liquid form that was
so very dangerous -- does this hold for oxygen at 40 psi?

LOX is the worst, as it is insanely concentrated. But, even pure
O2 at STP is pretty dangerous stuff. They've had some horrible fires
in operating rooms where pure oxygen the patient was breathing was allowed
to spill on surgical drapes and such and got ignited possibly by a
static discharge. You can't put that kind of fire out with a fire
extinguisher until all the oxygen is used up. The Air Force did some
testing just after WW-II to make sure pilots could operate long-term
while breathing pure O2. They had a chamber with a bunch of guys living in
pure O2, and had a fire when a guy changed a burned-out light bulb.
When the porcelain light socket started dripping flaming porcelain onto an
asbestos fire blanket and the asbestos caught on fire, they popped the door
open and escaped.

Nice story. Both porcelain and asbestos are fully oxidized--they will
not burn in oxygen--neither will glass--all are silicon dioxide. If you
don't believe me, take an oxyacetylene torch to a coke bottle and see if
you can light it. The news story I found doesn't mention either
asbestos or porcelain--it mentions that their clothing caught fire,
which is perfectly reasonable if it wasn't made from a fireproof
material. It also says that they were out 40 seconds after the fire
started and that they escaped by breaking a port with a hammer.
http://news.google.com/newspapers?nid=1873&dat=19670204
&id=Z28eAAAAIBAJ&sjid=o8kEAAAAIBAJ&pg=791,11880 11

The Apollo 11 fire is another case, of course, and they couldn't get
out
in time.

Jon

"Jon Elson" wrote in message
...

RogerN wrote:
snip

It would be nice to find a high pressure compressor compatible with
oxygen
to fill my own tanks. I priced a small 1/2HP oxygen compressor that went
to 2200PSI for tank filling, the price was almost $5000 for the
compressor. Anyone know of an affordable safe way to boost ~5PSI from an
oxygen concentrator to high enough pressure to be useful for a cutting
torch or even to fill an oxygen tank?

You don't need anywhere near 2200 PSI for a cutting torch, so that may
help keep the cost down. Partly, you are paying for liability insurance,
as anywhere pure Oxygen is used, there WILL be an occasional incident.

Jon

The 2200 PSI was to fill an Oxygen tank so I could have a volume of oxygen
at ~35 PSI for cutting. Pump up the tank overnight and have plenty of
oxygen for cutting, I'm guessing cutting takes more than the 5 liters per
minute that the concentrator delivers. For the glass working torches the
low PSI seems fine but they use large flame for large glasswork and can use
2 or 3 oxygen concentrators to supply the volume. I like torch welding, my
preference is TIG or Oxy/Acetylene, seems many places use the torch almost
exclusively for cutting.

For now I'll stick with oxygen tanks and keep concentrators in mind if I
should need one. Looks like a concentrator could be made with a few valves
and some 5A zeolite, might play with sometime for lab oxygen or something.

Tonight I connected my welding torch to propane and oxygen to try it on
borosilicate glass (pyrex). Seems like it should work good, I got the idea
because the glass working torches for that type of glass are premix with
tips like a welding torch. They even sell the Smith Little Torch at many of
the glass working suppliers. So I'll try to use my welding torch with
oxygen/propane for glass and see how that works for now.

RogerN

J. Clarke wrote:
In article ,
says...
Tim Wescott wrote:


I thought it was pure oxygen at high pressure or in liquid form that was
so very dangerous -- does this hold for oxygen at 40 psi?

LOX is the worst, as it is insanely concentrated. But, even pure
O2 at STP is pretty dangerous stuff. They've had some horrible fires
in operating rooms where pure oxygen the patient was breathing was allowed
to spill on surgical drapes and such and got ignited possibly by a
static discharge. You can't put that kind of fire out with a fire
extinguisher until all the oxygen is used up. The Air Force did some
testing just after WW-II to make sure pilots could operate long-term
while breathing pure O2. They had a chamber with a bunch of guys living in
pure O2, and had a fire when a guy changed a burned-out light bulb.
When the porcelain light socket started dripping flaming porcelain onto an
asbestos fire blanket and the asbestos caught on fire, they popped the door
open and escaped.

Nice story. Both porcelain and asbestos are fully oxidized--they will
not burn in oxygen--neither will glass--all are silicon dioxide. If you
don't believe me, take an oxyacetylene torch to a coke bottle and see if
you can light it. The news story I found doesn't mention either
asbestos or porcelain--it mentions that their clothing caught fire,
which is perfectly reasonable if it wasn't made from a fireproof
material. It also says that they were out 40 seconds after the fire
started and that they escaped by breaking a port with a hammer.
http://news.google.com/newspapers?nid=1873&dat=19670204
&id=Z28eAAAAIBAJ&sjid=o8kEAAAAIBAJ&pg=791,11880 11

As a result of the Apollo 1 spacecraft fire, the use of a pure oxygen
atmosphere during launch and ascent of Saturn V was abandoned by the U.
S. space program, according to NASA.

According to the Apollo Lunar Surface Journal, for Apollo 12, values
given for cabin pressure are 4.8 psi, and for normal operating suit
pressure, 3.8 psi. This suggests a pure oxygen environment for the Lunar
Module.

For Apollo 11, 12, & 14, during EVA preparation, the suit relative
pressures were 4.6 to 5.2 psi when the LM cabin pressure was 3.5 psi,
giving suit absolute pressures of 8.1 to 8.7 psi pure oxygen. At
earth's atmospheric pressure of 14.7 psi, this correlates to 55% to 60%
oxygen content, which gives an oxygen partial pressure of 8.1 to 8.7 psi.

According to the Apollo 12 ALSJ, the suits were already difficult to
bend at 3.8 psi relative pressure (when the LM cabin pressure was 3.5
psi). When the suit pressures were at about 4.5 psi relative pressure,
the suits were very stiff.

The following quotes are from a March 11, 1968 Aviation Week & Space
Technology article headlined "Flammability Tests Spur Two-Gas Apollo".

"Washington - Decision to use a two-gas atmosphere (60% oxygen, 40%
nitrogen) during manned Apollo on-the-pad preparations and in
pre-orbital flight reflects a basic inability to make the spacecraft
flameproof after 14 months of redesign that cost more than $100 million
and added about 2,000 lb. to the system.

"The decision (AW&ST, Mar. 4, p. 21) was forced on the National
Aeronautics and Space Administration after three series of flammability
tests on an Apollo command module boilerplate failed to satisfy
officials that changes would prevent the spread of fire under a
pure-oxygen environment."

The article goes on to mention how a 95% oxygen system at 6.2 psi which
would be orbital configuration developed problems in fire propagation tests.

Would not there have been serious flammability problems of such an
environment in the lunar module? The article concludes:

"By switching to a two-gas system for pre-flight and immediate
post-launch activities, NASA is willing to accept an added problem.
Astronauts will be breathing pure oxygen during that phase and they will
have to vent the spacecraft cabin during boost to orbit and repressurize
to 6 psi with oxygen to permit them to remove their helmets and work in
relative comfort.

"Possibility of the 40% of nitrogen causing bends if an emergency escape
has to be made during the launch phase was considered by officials less
hazardous than that of fire propagation in a one-gas system."

A Feb. 6, 1967 article in AW&ST indicates that when the Apollo program
was being planned, the primary reason for choosing a 5-psi cabin oxygen
system was weight considerations. Added weight (with a two-gas system)
would come from a mixture control system to keep the proper gas ratio.
Also, introduction of an oxygen-nitrogen or oxygen-helium environmental
control system for Apollo would have meant the addition of an airlock.

Just how dangerous was a pure oxygen environment in the ascent and
descent lunar module considered to be?

Here on earth, increasing the percentage of oxygen to slightly above 21%
dramatically increases probability of fires. According to The Anthropic
Cosmological Principle (p. 567) by Barrow and Tipler, "...the
probability of a forest fire being started by a lightning-bolt increases
70% for every 1% rise in oxygen concentration above the present 21%.
Above 25% very little of the vegetation on land would survive the
fires...". "At the present fraction of 21%, fires will not start at more
than 15% moisture content. Were the oxygen content to reach 25%, even
damp twigs and the grass of a rain forest would ignite."(p. 568).

Ralph René, in his book NASA Mooned America, provides a list of
government-sponsored testing that resulted in oxygen fires. René
extracted this information from Appendix G in Mission To The Moon by
Kennan & Harvey. Here are some tests on that list:

"September 9, 1962 - The first known fire occurred in the Space Cabin
Simulator at Brooks Air Force Base in a chamber using 100% oxygen at 5
psi. It was explosive and involved the carbon dioxide scrubber. Both
occupants collapsed from smoke inhalation before being rescued."

"November 17, 1962 - Another incident using 100% oxygen at 5 psi in a
chamber at the Navy Laboratory (ACEL). There were four occupants in the
chamber, but the simple replacing of a burned-out light bulb caused
their clothes to catch on fire. They escaped in 40 seconds but all
suffered burns. Two were seriously injured. In addition an asbestos
'safety' blanket caught fire and burned causing one man's hand to catch
fire."

"April 28, 1966 - More Apollo equipment was destroyed as it was being
tested under 100% oxygen and 5 psi at the Apollo Environmental Control
System in Torrance, CA."

"January 1, 1967 - The last known test was over three weeks before
Grissom, Chaffee & White suffered immolation. Two men were handling 16
rabbits in a chamber of 100% oxygen at 7.2 psi at Brooks Air Force Base
and all living things died in the inferno. The cause may have been as
simple as a static discharge from a rabbit's fur ... but we'll never know."

NASA subjected Grissom, White and Chaffee to over 90% pure oxygen at
over 16 psi in a test with live electrical circuits and switches being
thrown, and with a hatch that took more than three minutes to open,
resulting in the fatal Apollo 1 fire.

Bill Kaysing, in his book We Never Went To The Moon, states, in Chapter
9 titled "Murder By Negligence On Pad 34", "If any two documents lend
credibility to the contention that the Apollo flights were faked, they
are most certainly the Baron Report and the Phillips Report. They were
authored by two men of obvious integrity and dedication. Although from
diverse backgrounds, both Tom Baron and Sam Phillips were in total
agreement on one basic premise, i.e., that North American Aviation and
its sponsor, NASA, were totally unequal to the task of assuring even one
successful flight to the moon!"

Why did NASA decide to subject Grissom, White and Chaffee to more than
90% pure oxygen at over 16 psi in a test with live electrical circuits
and switches being thrown, and with a hatch that took more than three
minutes to open, resulting in the fatal Apollo 1 fire?
--
Steve W.

On Mon, 10 Sep 2012 22:28:52 -0400, "Jim Wilkins"
wrote:

"Larry Jaques" wrote in message
Cite, please?

http://en.wikipedia.org/wiki/Partial_pressure

Thanks. Still having trouble wrapping my head around that.
Is the difference that of the compressibility of the gases, or?

"The partial volume of a particular gas is the volume which the gas
would have if it alone occupied the volume.", do they mean that if
there were 21 molecules of oxygen and 79 molecules of nitrogen
compressed into a 1 CC container, if the nitrogen were removed, the
oxygen would be at its partial volume?

Is "the volume" they refer to 1 CC or 0.21 CC in my example?

(Last chem class was high school level in 1970; "molar fraction" is
still recognized.)

Is this a semantics test question?

--
Courage and perseverance have a magical talisman, before
which difficulties disappear and obstacles vanish into air.
-- John Quincy Adams

"Larry Jaques" wrote in message
...
On Mon, 10 Sep 2012 22:28:52 -0400, "Jim Wilkins"
wrote:

"Larry Jaques" wrote in message

Cite, please?

http://en.wikipedia.org/wiki/Partial_pressure

Thanks. Still having trouble wrapping my head around that.
Is the difference that of the compressibility of the gases, or?

"The partial volume of a particular gas is the volume which the gas
would have if it alone occupied the volume.", do they mean that if
there were 21 molecules of oxygen and 79 molecules of nitrogen
compressed into a 1 CC container, if the nitrogen were removed, the
oxygen would be at its partial volume?

Is "the volume" they refer to 1 CC or 0.21 CC in my example?

(Last chem class was high school level in 1970; "molar fraction" is
still recognized.)

Is this a semantics test question?

Homework:
http://chemistry.about.com/od/worked...alpressure.htm

On Tue, 11 Sep 2012 00:46:10 -0400, "Jim Wilkins"
wrote:

"Larry Jaques" wrote in message
.. .
On Mon, 10 Sep 2012 22:28:52 -0400, "Jim Wilkins"
wrote:

"Larry Jaques" wrote in message

Cite, please?

http://en.wikipedia.org/wiki/Partial_pressure

Thanks. Still having trouble wrapping my head around that.
Is the difference that of the compressibility of the gases, or?

"The partial volume of a particular gas is the volume which the gas
would have if it alone occupied the volume.", do they mean that if
there were 21 molecules of oxygen and 79 molecules of nitrogen
compressed into a 1 CC container, if the nitrogen were removed, the
oxygen would be at its partial volume?

Is "the volume" they refer to 1 CC or 0.21 CC in my example?

(Last chem class was high school level in 1970; "molar fraction" is
still recognized.)

Is this a semantics test question?

Homework:
http://chemistry.about.com/od/worked...alpressure.htm

I see it and understand how they got the figures, but I'm -still-
missing some component to grok it.

Could you answer my questions about my example, please?

--
Courage and perseverance have a magical talisman, before
which difficulties disappear and obstacles vanish into air.
-- John Quincy Adams

RogerN wrote:
"Jon Elson" wrote in message
...


RogerN wrote:
snip

It would be nice to find a high pressure compressor compatible with
oxygen
to fill my own tanks. I priced a small 1/2HP oxygen compressor that went
to 2200PSI for tank filling, the price was almost $5000 for the
compressor. Anyone know of an affordable safe way to boost ~5PSI from an
oxygen concentrator to high enough pressure to be useful for a cutting
torch or even to fill an oxygen tank?


You don't need anywhere near 2200 PSI for a cutting torch, so that may
help keep the cost down. Partly, you are paying for liability insurance,
as anywhere pure Oxygen is used, there WILL be an occasional incident.

Jon


The 2200 PSI was to fill an Oxygen tank so I could have a volume of oxygen
at ~35 PSI for cutting. Pump up the tank overnight and have plenty of
oxygen for cutting, I'm guessing cutting takes more than the 5 liters per
minute that the concentrator delivers. For the glass working torches the
low PSI seems fine but they use large flame for large glasswork and can use
2 or 3 oxygen concentrators to supply the volume. I like torch welding, my
preference is TIG or Oxy/Acetylene, seems many places use the torch almost
exclusively for cutting.

For now I'll stick with oxygen tanks and keep concentrators in mind if I
should need one. Looks like a concentrator could be made with a few valves
and some 5A zeolite, might play with sometime for lab oxygen or something.

Tonight I connected my welding torch to propane and oxygen to try it on
borosilicate glass (pyrex). Seems like it should work good, I got the idea
because the glass working torches for that type of glass are premix with
tips like a welding torch. They even sell the Smith Little Torch at many of
the glass working suppliers. So I'll try to use my welding torch with
oxygen/propane for glass and see how that works for now.

A friend bought some tips for oxy propane that had been modified by the
supplier from OA tips, the only difference appears to be a
countersinking of the end of the tip. I presume it is some sort of flame
retention feature. I've not compared the behaviour but have a similar
set of OA tips so could try both on oxy propane to see if there's a
difference.

RogerN

On 9/11/2012 4:55, Larry Jaques wrote:
On Mon, 10 Sep 2012 20:51:05 +0300, Kristian Ukkonen
On 9/10/2012 19:49, Tim Wescott wrote: On Sun, 09 Sep 2012 21:57:01
-0500, Jon Elson wrote:
RogerN wrote:
I've seen a few of the suppliers that sell torches for glassblowing
also sell oxygen concentrators so you can run the torches without
having to buy oxygen in tanks. I'm wondering if this would be
beneficial to metalworkers that do a lot of torch work.
http://www.sundanceglass.com/oxygen-concentrator.htm
They have 7PSI 5LPM for $275. This may be OK for oxy/acetylene welding
but
not enough pressure (or volume) for cutting. So what about adapting an
oil free compressor and a tank to give you enough pressure and volume
for cutting torch operation. Seems this price is getting competitive
with the price of tank and contents, or at least by the time you have
to get a couple of refills.
Pure Oxygen is extremely dangerous. Only certain metals and plastics
are compatible with it. For instance, a fingerprint left inside an
oxygen system is enough to cause a fire that will set the metal lines on
fire.
I thought it was pure oxygen at high pressure or in liquid form that was
so very dangerous -- does this hold for oxygen at 40 psi?

Normal compressor has oxygen at about 2.1bar (30psi) if
tank is at 10bar.. 21% of air is oxygen.. Compressor with
higher tank pressure has higher oxygen partial pressure.

No, normal compressor at 10 bar tank pressure has oxygen (in the air)
at 10 bar. There is no separation in the tank, at least not that I've
ever heard of. Why would the hydrogen (and other gases) compress at a
higher pressure? That's daft, man!

I'm afraid you don't understand what partial pressure means.

http://en.wikipedia.org/wiki/Partial_pressure

http://chemistry.about.com/od/worked...alpressure.htm


If the compressor compresses normal air to 10bar in tank, there
will be partial pressures of gasses about:
7.8bar nitrogen
2.1bar oxygen
0.09bar argon
0.0003bar CO2
.....
0.0000005bar hydrogen
etc. based on how much of each gas there is in air.
There is not much hydrogen in air, really.

If you take the nitrogen and all other gasses, except oxygen, away,
there still will be the oxygen pressure of 2.1bar left in tank.
You could achieve the same (as above compressing air) by pumping
vacuum to tank, filling 7.8bar N2, 2.1bar O2, 0.09bar Ar etc..
The end result would be exactly the same.


This doesn't take into account that the compressor propably
has a different compression ratio for different gasses, so the
partial pressures above are not very accurate, but that is
not the point here anyway.

Normal "instrument air" (synthetic air) is 21% oxygen at 200bar
in a bottle.. Nothing special required yet at partial pressure of
oxygen at 42bar. Just normal nitrogen pressure reducer etc..
This is all stated by the "safety sheet" of the product by
gas company.
Cite, please?

My documents are in Finnish so I think that wouldn't help much.
Google found these english MSDSs for synthetic air and pure oxygen:

http://www.praxair.com/praxair.nsf/AllContent/A3552DAFCB8D265685256A86008095F6/$File/p4560j.pdf

http://www.praxair.com/praxair.nsf/AllContent/E88BE35D13EF81F685256A860081E837/$File/p4638h.pdf

Notice the significant differences in precautions etc..

Kristian Ukkonen.

On 9/11/2012 7:24, Larry Jaques wrote:
On Mon, 10 Sep 2012 22:28:52 -0400, "Jim Wilkins"
wrote:

"Larry Jaques" wrote in message
Cite, please?

http://en.wikipedia.org/wiki/Partial_pressure

Thanks. Still having trouble wrapping my head around that.
Is the difference that of the compressibility of the gases, or?

"The partial volume of a particular gas is the volume which the gas
would have if it alone occupied the volume.", do they mean that if
there were 21 molecules of oxygen and 79 molecules of nitrogen
compressed into a 1 CC container, if the nitrogen were removed, the
oxygen would be at its partial volume?

Is "the volume" they refer to 1 CC or 0.21 CC in my example?

Both gasses are in the same volume, 1cc.
The molecules of the gasses are mixed in the space.

As pV/T=constant, what happens is that when you remove the
nitrogen the pressure drops to partial pressure of oxygen.
If you want to keep pressure same, you need to change volume
to the partial volume of oxygen. You must keep temperature constant.

So at first:
1cc, 21% O2, 79% N2, total pressure 10bar
now we take nitrogen away, the pressure becomes partial pressure of O2
1cc, 100% O2, pressure 2.1bar
now we compress oxygen to get original pressure
0.21cc, 100% O2, pressure 10bar
This 0.21cc is the partial volume of oxygen.

You can also calculate it from pV/T=nR..
http://en.wikipedia.org/wiki/Ideal_gas_law

I hope this helps. Partial volume is not very usefull concept, IMHO,
while the partial pressure is a very usefull concept in real life.

Kristian Ukkonen.

On 09/10/2012 11:24 PM, Larry Jaques wrote:
On Mon, 10 Sep 2012 22:28:52 -0400, "Jim Wilkins"
wrote:

"Larry wrote in message
Cite, please?

http://en.wikipedia.org/wiki/Partial_pressure

Thanks. Still having trouble wrapping my head around that.
Is the difference that of the compressibility of the gases, or?

It's not that hard to understand. If you have air with 21% (by
volume) oxygen at an absolute pressure of 10 bar, the concentration
of oxygen molecules per unit volume is that same as for pure
oxygen at 2.1 bar.

--
Bob Nichols AT comcast.net I am "RNichols42"

On Sun, 9 Sep 2012 21:50:58 -0500, "RogerN" wrote:


I've seen a few of the suppliers that sell torches for glassblowing also
sell oxygen concentrators so you can run the torches without having to buy
oxygen in tanks. I'm wondering if this would be beneficial to metalworkers
that do a lot of torch work.

http://www.sundanceglass.com/oxygen-concentrator.htm

They have 7PSI 5LPM for $275. This may be OK for oxy/acetylene welding but
not enough pressure (or volume) for cutting. So what about adapting an oil
free compressor and a tank to give you enough pressure and volume for
cutting torch operation. Seems this price is getting competitive with the
price of tank and contents, or at least by the time you have to get a couple
of refills.

It would be nice to find a high pressure compressor compatible with oxygen
to fill my own tanks. I priced a small 1/2HP oxygen compressor that went to
2200PSI for tank filling, the price was almost $5000 for the compressor.
Anyone know of an affordable safe way to boost ~5PSI from an oxygen
concentrator to high enough pressure to be useful for a cutting torch or
even to fill an oxygen tank?

Also, is it OK to run an oxy/acetylene torch on oxy/propane? I know they
have different tips for propane for the cutting torch but not sure about the
welding torch. From my understanding I know you need Grade T hose instead
of the grade R, but not sure if there is any difference in the brazing torch
tips.

RogerN


Propane has less heat value so you generally have to use a larger tip
and you can't weld with it although you can cut with it.

It is very common in some of the developing countries, maybe in other
places too, to use oxy/cooking gas.

On Mon, 10 Sep 2012 22:03:08 -0500, "RogerN"
wrote:

"Jon Elson" wrote in message
m...

RogerN wrote:
snip

It would be nice to find a high pressure compressor compatible with
oxygen
to fill my own tanks. I priced a small 1/2HP oxygen compressor that went
to 2200PSI for tank filling, the price was almost $5000 for the
compressor. Anyone know of an affordable safe way to boost ~5PSI from an
oxygen concentrator to high enough pressure to be useful for a cutting
torch or even to fill an oxygen tank?

You don't need anywhere near 2200 PSI for a cutting torch, so that may
help keep the cost down. Partly, you are paying for liability insurance,
as anywhere pure Oxygen is used, there WILL be an occasional incident.

Jon

The 2200 PSI was to fill an Oxygen tank so I could have a volume of oxygen
at ~35 PSI for cutting. Pump up the tank overnight and have plenty of
oxygen for cutting, I'm guessing cutting takes more than the 5 liters per
minute that the concentrator delivers. For the glass working torches the
low PSI seems fine but they use large flame for large glasswork and can use
2 or 3 oxygen concentrators to supply the volume. I like torch welding, my
preference is TIG or Oxy/Acetylene, seems many places use the torch almost
exclusively for cutting.

For now I'll stick with oxygen tanks and keep concentrators in mind if I
should need one. Looks like a concentrator could be made with a few valves
and some 5A zeolite, might play with sometime for lab oxygen or something.

Tonight I connected my welding torch to propane and oxygen to try it on
borosilicate glass (pyrex). Seems like it should work good, I got the idea
because the glass working torches for that type of glass are premix with
tips like a welding torch. They even sell the Smith Little Torch at many of
the glass working suppliers. So I'll try to use my welding torch with
oxygen/propane for glass and see how that works for now.

You really don't need a cylinder transfill compressor to get up to
2200 PSI - but even if you shoot for 150 to 200 PSI in a large
80-gallon or 100-gallon receiver cylinder, the compressor and piping
and /everything/ has to be properly rated for use with 100% oxygen,
and scrupulously cleaned inside for same. Otherwise you run the very
real risk of the whole mess blowing up in your face.

Any oil or grease, or non-compatible thread sealant or metal alloy in
a fitting, or a hundred other things can go really wrong.

Here's one place to look for free:
http://www.hq.nasa.gov/office/codeq/...ed/1740151.pdf
It's "Canceled" because they want you to go BUY a copy of ASTM Manual
36 and follow that. But there's a lot of good information in there.

There are way too many things that can set off a fire - even dumb crap
like opening a valve and letting high-pressure Oxygen into a capped
pipe or the next valve in the line being closed - the hammer effect of
the pressure wave hitting the closed end of the pipe can be enough to
set off a reaction.

Or a capped tee turns into a resonance chamber (like a coke-bottle
whistle) and the resonant energy in the chamber can be enough.

Aluminum fittings or piping can be chancy - Anodized may be safe, but
you scrape it and expose clean reactive metal, and that can be enough.

Any solid debris gets inside, swept along with the flow, then impacts
the wall of an elbow or tee fitting, that can be enough.

THIS IS SERIOUS **** - Don't experiment with things that can and will
kill you or a loved one (and rather messily) given half a chance.

-- Bruce --

On Tue, 11 Sep 2012 23:02:58 +0300, Kristian Ukkonen
wrote:

On 9/11/2012 7:24, Larry Jaques wrote:
On Mon, 10 Sep 2012 22:28:52 -0400, "Jim Wilkins"
wrote:

"Larry Jaques" wrote in message
Cite, please?

http://en.wikipedia.org/wiki/Partial_pressure

Thanks. Still having trouble wrapping my head around that.
Is the difference that of the compressibility of the gases, or?

"The partial volume of a particular gas is the volume which the gas
would have if it alone occupied the volume.", do they mean that if
there were 21 molecules of oxygen and 79 molecules of nitrogen
compressed into a 1 CC container, if the nitrogen were removed, the
oxygen would be at its partial volume?

Is "the volume" they refer to 1 CC or 0.21 CC in my example?

Both gasses are in the same volume, 1cc.
The molecules of the gasses are mixed in the space.

As pV/T=constant, what happens is that when you remove the
nitrogen the pressure drops to partial pressure of oxygen.
If you want to keep pressure same, you need to change volume
to the partial volume of oxygen. You must keep temperature constant.

So at first:
1cc, 21% O2, 79% N2, total pressure 10bar
now we take nitrogen away, the pressure becomes partial pressure of O2
1cc, 100% O2, pressure 2.1bar
now we compress oxygen to get original pressure
0.21cc, 100% O2, pressure 10bar
This 0.21cc is the partial volume of oxygen.

You can also calculate it from pV/T=nR..
http://en.wikipedia.org/wiki/Ideal_gas_law

I hope this helps. Partial volume is not very usefull concept, IMHO,
while the partial pressure is a very usefull concept in real life.

Thanks, Kristian. That answered all my questions and firmed up my
grasp of the concept.

Did the concept of partial pressure come about to service the needs of
those who physically fill tanks of gas, I wonder?

--
Courage and perseverance have a magical talisman, before
which difficulties disappear and obstacles vanish into air.
-- John Quincy Adams

"Larry Jaques" wrote in message
Did the concept of partial pressure come about to service the needs
of
those who physically fill tanks of gas, I wonder?

Nope.

Along with the other gas laws it dates from ~1800 when amateur
experimenters finally made sense of chemistry.
http://en.wikipedia.org/wiki/Dalton's_law
http://en.wikipedia.org/wiki/Antoine_Lavoisier

It was an enormous leap from a level not that much higher than the
Romans. Science was pretty much still mystic alchemy in 1780, by the
1820s we understood electricity, magnetism and thermodynamics and that
Earth, Air, Fire and Water weren't the basic elements of matter, but
levels of energy. Likewise that's the period when metalworking
advanced from saws and chisels to lathes, planers and milling
machines.

jsw

J. Clarke wrote:


Nice story. Both porcelain and asbestos are fully oxidized--they will
not burn in oxygen--neither will glass--all are silicon dioxide.
Right, I agree with you. But, there must have been other materials in small
quantities in these items that were still able to be oxidized.
Or, perhaps as you say, the original account got muddied a bit over
time. Still, I wanted to caution the OP that low pressure pure
O2 is still VERY dangerous stuff, and needs to be treated with utmost
caution. And that this partial pressure business is completely wrong.
compressed air where the O2 partial pressure equals atmospheric pressure
is not the same as pure O2 at atmospheric pressure. I am not enough of
a physicist to know why, but I am quite sure this is true. There is a
bunch of lube oil that has settled in the bottom of my air compressor tank,
and at 100 PSI, the O2 partial pressure is roughly the same as pure O2 at
atmospheric pressure. No problems, and everybody does this. But, put
pure O2 in that tank at one atmosphere, and I am fairly sure something very
bad could happen.

Jon

On Sep 14, 6:11*pm, Jon Elson wrote:
*And that this partial pressure business is completely wrong.
compressed air where the O2 partial pressure equals atmospheric pressure
is not the same as pure O2 at atmospheric pressure. *I am not enough of
a physicist to know why, but I am quite sure this is true. *There is a
bunch of lube oil that has settled in the bottom of my air compressor tank,
and at 100 PSI, the O2 partial pressure is roughly the same as pure O2 at
atmospheric pressure. *No problems, and everybody does this. *But, put
pure O2 in that tank at one atmosphere, and I am fairly sure something very
bad could happen.

Jon

You are right. Take a tank of pure oxygen at atmospheric pressure and
another tank with air at a pressure where the partial pressure of the
oxygen is at atmospheric pressure. The one tank has a much lower mass
of gas in it. So if you add equal amounts of energy to both tanks,
the tank with only oxygen will be higher in temperature.

In the tank with only oxygen the mean free path will be longer.


Dan


Dan

On 2012-09-14, Jon Elson wrote:
J. Clarke wrote:


Nice story. Both porcelain and asbestos are fully oxidized--they will
not burn in oxygen--neither will glass--all are silicon dioxide.
Right, I agree with you. But, there must have been other materials in small
quantities in these items that were still able to be oxidized.

Perhaps it was the glass-epoxy printed circuit boards
(fiberglass bound with epoxy) which burned so spectacularly when we lost
a couple of astronauts on the launch pad. Over time, people could
forget the "-epoxy" of "glass-epoxy" and claim that it was the glass
which burned. :-)

Or, perhaps as you say, the original account got muddied a bit over
time. Still, I wanted to caution the OP that low pressure pure
O2 is still VERY dangerous stuff, and needs to be treated with utmost
caution. And that this partial pressure business is completely wrong.
compressed air where the O2 partial pressure equals atmospheric pressure
is not the same as pure O2 at atmospheric pressure.

IIRC, that capsule (one of the Gemini series, since there were
two astronauts in it?) was being run at the partial pressure of oxygen
from the atmosphere (e.g. about 20% of the full atmospheric pressure) to
minimize the problems with seals and leaks, to supply enough oxygen to
keep the astronauts alive for one of the longer flights. If it was
truly just the partial pressure, it would have been below atmospheric
pressure, and any leaks while sitting on the pad would have been coming
in instead of going out.

I am not enough of
a physicist to know why, but I am quite sure this is true. There is a
bunch of lube oil that has settled in the bottom of my air compressor tank,
and at 100 PSI, the O2 partial pressure is roughly the same as pure O2 at
atmospheric pressure. No problems, and everybody does this. But, put
pure O2 in that tank at one atmosphere, and I am fairly sure something very
bad could happen.

I think that the presence of the nitrogen (and to a much lesser
degree, the other things in our air) diluted the effect of nothing but
oxygen molecules bouncing off everything.

Yes -- even at 20% of atmosphere pressure (partial pressure of
oxygen), the puddle of oil would be bad news with the pure oxygen --
even without the extra pressure you are talking about pumping in there.
Add that, and you would be about 20 PSIG (PSI above atmospheric
pressure, as equal to the partial pressure of oxygen in a 100 PSI tank
of air.)

Be careful,
DoN.

--
Remove oil spill source from e-mail
Email: | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---

"DoN. Nichols" wrote in
:

On 2012-09-14, Jon Elson wrote:
J. Clarke wrote:


Nice story. Both porcelain and asbestos are fully oxidized--they
will not burn in oxygen--neither will glass--all are silicon
dioxide.
Right, I agree with you. But, there must have been other materials
in small quantities in these items that were still able to be
oxidized.

Perhaps it was the glass-epoxy printed circuit boards
(fiberglass bound with epoxy) which burned so spectacularly when we
lost a couple of astronauts on the launch pad. Over time, people
could forget the "-epoxy" of "glass-epoxy" and claim that it was the
glass which burned. :-)

I think one of the biggest sources of fuel was the foam seat cushions. I
think there was also plenty of nylon fabric & Velcro around.

Doug White

"Doug White" wrote in message
. ..
"DoN. Nichols" wrote in
:

On 2012-09-14, Jon Elson wrote:
J. Clarke wrote:


Nice story. Both porcelain and asbestos are fully oxidized--they
will not burn in oxygen--neither will glass--all are silicon
dioxide.
Right, I agree with you. But, there must have been other materials
in small quantities in these items that were still able to be
oxidized.

Perhaps it was the glass-epoxy printed circuit boards
(fiberglass bound with epoxy) which burned so spectacularly when we
lost a couple of astronauts on the launch pad. Over time, people
could forget the "-epoxy" of "glass-epoxy" and claim that it was the
glass which burned. :-)

I think one of the biggest sources of fuel was the foam seat cushions. I
think there was also plenty of nylon fabric & Velcro around.

Doug White

It was Apollo 1. The astronaughts who died were Grissom, Chaffee and White.
They were doing what they thought was a routine test on the launch pad. The
capsule had a pure O2 atmosphere pressurized to 2 psi above atmosphere. The
ignition source was most likely some chaffed wires, but at that level of O2,
fire will find something to burn.

Particularly the 34 sq feet of velcro installed in the cockpit.

I have seen films of burn tests on the stuff and in a pressurized O2 it is
like flashpowder.

The inward opening hatch could not be opened against the interior pressure
and all three astronauts burned to death.

Paul K. Dickman

I have a large (28")cutting torch that has 3 Airlines, does anybody know what this is used for? Does it use 2 oxygen lines?

wrote:
I have a large (28")cutting torch that has 3 Airlines, does anybody
know what this is used for? Does it use 2 oxygen lines?

Most of the 3 line torches are used in cutting machines. Usually they
have one fuel line (Acetylene or propane), one low flow oxygen (used
with the fuel to preheat the steel prior to the cut) and one high flow
oxygen to do the cutting.

--
Steve W.

On Sun, 1 May 2016 05:50:46 -0700 (PDT), wrote:

I have a large (28")cutting torch that has 3 Airlines, does anybody know what this is used for? Does it use 2 oxygen lines?

I believe the third uses high-pressure oxygen to aid in cutting depth.

Well, unless it's one of those special torch setups. Could
be it's an oxygen/acetylene/methane torch. One line goes to the
oxygen tank, one to the acetylene tank, and the other goes up your
bum. Just make sure to use check valves in all lines. I understand
that backfires can be truly distressing.

--
EAT RIGHT, KEEP FIT, DIE ANYWAY.
--anon

Aw, Hell. Gimme CHOCOLATE!
--LJ