Just got myself a co2 tank designed to fill small paintball tanks.

I plan to use this mostly for combat robotics and possibly
for a MIG set up when I get MIG.

I do have SCUBA experience, an air compressor and a TIG set up. But
co2 seems to be a bit of a different horse as it is stored in liquid
form.

Looking for information sources on handling this safely.
Favorite books, web sites, free advice...


Tanks :-) for any help.

DOC

wrote:

Just got myself a co2 tank designed to fill small paintball tanks.

I plan to use this mostly for combat robotics and possibly
for a MIG set up when I get MIG.

I do have SCUBA experience, an air compressor and a TIG set up. But
co2 seems to be a bit of a different horse as it is stored in liquid
form.

Looking for information sources on handling this safely.
Favorite books, web sites, free advice...

Tanks :-) for any help.

DOC

SCUBA tanks are a lot higher pressure than CO2. The only real issue with
CO2 is the potential for frostbite if you manage to release it in liquid
form on yourself. Just download the MSDS from the Airgas site.

"Pete C." wrote in message
...
wrote:

Just got myself a co2 tank designed to fill small paintball tanks.

I plan to use this mostly for combat robotics and possibly
for a MIG set up when I get MIG.

I do have SCUBA experience, an air compressor and a TIG set up. But
co2 seems to be a bit of a different horse as it is stored in liquid
form.

Looking for information sources on handling this safely.
Favorite books, web sites, free advice...

Tanks :-) for any help.

DOC

SCUBA tanks are a lot higher pressure than CO2. The only real issue with
CO2 is the potential for frostbite if you manage to release it in liquid
form on yourself. Just download the MSDS from the Airgas site.

Not quite the only issue. Even a CO2 tank in a fire is a bomb, even it if
puts the fire out when it blows. And if you happen to have confined spaces,
particularly a cellar or similar, there is a real asphyxiation risk from a
leak. Fire fighters using CO2 know that if they get a taste in the mouth
like a fizzy drink then it is time to get out.

Just got myself a co2 tank designed to fill small paintball tanks.

I plan to use this mostly for combat robotics and possibly
for a MIG set up when I get MIG.

Did you get one for paintball filling or for welding? the paintball unit has
a tube inside the tank so liquid comes out when its upright, can't be used
to weld. A weld tank has to be upside down to dispense liquid.

a small tube and valve kit is sold to hook the paintball tank up to the big
tank. Comes with directions. basically you vent a little gas out of the
paintball can and the pressure difference forces liquid across. Biggest
issue with filling is freezing a line up - go slow.

DON'T OVERFILL. You need 20% headspace. Use a scale. "The kid" filled
paintball tanks for all his friends when he was home. He overfilled one and,
not knowing of a problem, put it in the car and started driving. It popped
the relief valve with a bang while they were driving. They almost had an
accident trying to jump out of the car cause they thought a bomb had went
off.

Karl

Newshound wrote:
Not quite the only issue. Even a CO2 tank in a fire is a bomb,...

I don't think so - they have pressure relief valves. Plugs, actually, IIRC.

And if you happen to have confined spaces,
particularly a cellar or similar, there is a real asphyxiation risk from a
leak. ...

I don't think so - breathing just a little would be so distressing that
you'd immediately get-the-hell-out. It's the rise in CO2 concentration
in our lungs that makes it so hard to hold your breath for very long.
There's still plenty of oxygen in your lungs but the rising CO2 says:
BREATH! BREATH!! You start experiencing that in your cellar and you'll
be out of there long before asphyxiation is a risk.

Bob

Hi Bob,
My experience has been a bit different to yours. Regarding CO2 cyllinders
as a potential source of explosions, about 3 weeks ago my best friend was in
his caravan when it caught on fire. he had a mid size co2 cyllinder inside,
which ruptured. The temperature was extremely hot inside the van, hot
enough that it melted all the aluminum sheeting. The cyllinder ruptured in
an unusual way, splitting right down the side. It blew through the
relatively thin wall and landed about 30 feet away on the road. I was
outside the van trying to get in when it exploded. the safety release valve
did not operate, there is a current investigation being made by BOC as to
why.

Regarding risk of asphyxiation, this is a very real risk. I work in mount
isa australia, a fairly large mining town. The company i work for is
frequently doing confined spaces work inside tanks and other vessels. we
follow standard procedures of using forced fan ventillation and extraction,
an air sniffing machine and having a spotter who is qualified to do a
confined spaces recovery in case of the worst. We have thankfully never
experienced an incident, but we do receive safety bulletins from other
companies as part of our safety network. I have seen quite a few bulletins
concerning deaths in these types of situations. One particular case that
comes to mind ivolved the death of 3 people - the person in the confined
space, and the deaths of two people trying to recover him.

We did have a near miss last year while welding inside a copper smelting
pot. These pots are used by the mine and hold about 90 tonnes of copper.
You climb up a ladder to get inside, its like sitting in a giant coffee cup.
We weld tham back up with a dual shield filler with CO2 as the gas. The two
staff welding the pot had gone for lunch and had turned off the extraction
system for some peace and quiet. What had happened was the valve on the
welding unit which controls the gas flow had stuck 'on'. gas was
continuously pouring out the end of the nozzle at 20 litres a minute.

They had a fairly long lunch and there wasnt much wind blowing that day.
the Co2 filled up the copper pot much like water - displacing all the
breathable air. The guys came back, and the welder climbed into the pot
while the other fellow went to turn the extractor back on. once he was
inside the pot he was overcome pretty quickly by dizziness and was unable to
get out. Thankfully the extractor system came on and fresh air was forced
inside. It was a big wake up call for us.

Ive never actually breathed Co2 myself, though i have done my share of
confined spaces welding. Im very concerned about following the right
procedures for this type of work.

Best Regards,
Shaun

"Bob Engelhardt" wrote in message
. ..
Newshound wrote:
Not quite the only issue. Even a CO2 tank in a fire is a bomb,...

I don't think so - they have pressure relief valves. Plugs, actually,
IIRC.

And if you happen to have confined spaces, particularly a cellar or
similar, there is a real asphyxiation risk from a leak. ...

I don't think so - breathing just a little would be so distressing that
you'd immediately get-the-hell-out. It's the rise in CO2 concentration in
our lungs that makes it so hard to hold your breath for very long. There's
still plenty of oxygen in your lungs but the rising CO2 says: BREATH!
BREATH!! You start experiencing that in your cellar and you'll be out of
there long before asphyxiation is a risk.

Bob

On Aug 17, 4:38 pm, "Pete C." wrote:

....

SCUBA tanks are a lot higher pressure than CO2. The only real issue with
CO2 is the potential for frostbite if you manage to release it in liquid
form on yourself. Just download the MSDS from the Airgas site.

I recall the air tanks were around 3000 PSI and gather that co2 is
somewhere
around the 600 mark.

And I gather that the co2 stays at a constant pressure as long as
there is liquid in the tank. That sound right?

And paintball tanks are loaded by weight, not pressure. So there's
no point in putting a gage on a tank?

DOC

Shaun Van Poecke wrote:
... The cyllinder ruptured in
an unusual way, splitting right down the side. ... the safety release valve
did not operate, ...

... the Co2 filled up the copper pot ... the welder climbed into the pot
... once he was
inside the pot he was overcome pretty quickly by dizziness and was unable to
get out. ...

Shaun - thanks for the real-world input. Too many of our posts are
speculation, sometimes not based on much knowledge.

While accepting that CO2 is more dangerous than I believed, I'm still
going to store my cylinder in the cellar. It's a probability thing
(like most things in life). The probability that there'll be a fire AND
the safety will fail is small enough for me. Likewise the probability
that my cylinder will leak fast enough to fill up my drafty basement is
small enough. It's a small cylinder.

Bob

On Aug 17, 5:03 pm, "Karl Townsend"
wrote:

....


Did you get one for paintball filling or for welding?

I don't plan to do any paintball. It's more for combat robotics. But I
would assume
that. from a procedure point of view, this would be like paintball.

The tank I have is for paintball and has a siphon.

the paintball unit has
a tube inside the tank so liquid comes out when its upright, can't be used
to weld. A weld tank has to be upside down to dispense liquid.

Does securing the tank upside down make any sense?


a small tube and valve kit is sold to hook the paintball tank up to the big
tank. Comes with directions. basically you vent a little gas out of the
paintball can and the pressure difference forces liquid across. Biggest
issue with filling is freezing a line up - go slow.

I've got a small tube like that. Made by Pure Energy. Didn't get any
instructions.
But it wasn't too hard to figure out.

I was able to use it to "fill" a 9 oz tank but don't have a scale to
check the
wieght.


DON'T OVERFILL. You need 20% headspace. Use a scale. "The kid" filled
paintball tanks for all his friends when he was home. He overfilled one and,
not knowing of a problem, put it in the car and started driving. It popped
the relief valve with a bang while they were driving. They almost had an
accident trying to jump out of the car cause they thought a bomb had went
off.

When you say don't overfill I assume you mean that there shouldn't be
too much
liquid in a tank?


Thanks,
DOC

On Sat, 18 Aug 2007 11:07:43 -0700, wrote:
On Aug 17, 4:38 pm, "Pete C." wrote:

...

SCUBA tanks are a lot higher pressure than CO2. The only real issue with
CO2 is the potential for frostbite if you manage to release it in liquid
form on yourself. Just download the MSDS from the Airgas site.

I recall the air tanks were around 3000 PSI and gather that co2 is
somewhere
around the 600 mark.

Our SCBA tanks are pressurized up to 2215PSI. I have no idea where that
number comes from. There are also 6000PSI tanks I seem to recall
but...in a fire, one 2215PSI tank is all I can go through without being
tired, not sure how much longer the 6000PSI would last but, longer than
me.

And paintball tanks are loaded by weight, not pressure. So there's
no point in putting a gage on a tank?

Probably not. Propane tanks are similar, pressure is nearly irrelevant,
level of liquid is the key. If, as you say, CO2 is in a liquid form in
the tank.

On Aug 17, 7:02 pm, "Shaun Van Poecke"
wrote:


....

an unusual way, splitting right down the side. It blew through the
relatively thin wall and landed about 30 feet away on the road. I was
outside the van trying to get in when it exploded. the safety release valve
did not operate, there is a current investigation being made by BOC as to
why.

This sounds to me like there was a problem with the overpressure burst
disk. Should have gone before the tank. Maybe the heat caused it to
not preform as it should have.


....


We did have a near miss last year while welding inside a copper smelting
pot. These pots are used by the mine and hold about 90 tonnes of copper.
You climb up a ladder to get inside, its like sitting in a giant coffee cup.

Ah... I should be OK here. I don't drink that much coffee! :-)oo

We weld tham back up with a dual shield filler with CO2 as the gas. The two
staff welding the pot had gone for lunch and had turned off the extraction
system for some peace and quiet. What had happened was the valve on the
welding unit which controls the gas flow had stuck 'on'. gas was
continuously pouring out the end of the nozzle at 20 litres a minute.



Actually this story does bring up a good point. I usually keep the
tank in an area that
is relatively closed in. So if the tank were to start leaking, the co2
might be able to
build up in the area.

Appreciate the comments.

DOC

And if you happen to have confined spaces, particularly a cellar or
similar, there is a real asphyxiation risk from a leak. ...

I don't think so - breathing just a little would be so distressing that
you'd immediately get-the-hell-out. It's the rise in CO2 concentration
in our lungs that makes it so hard to hold your breath for very long.
There's still plenty of oxygen in your lungs but the rising CO2 says:
BREATH! BREATH!! You start experiencing that in your cellar and you'll
be out of there long before asphyxiation is a risk.

Bob

In the UK I believe there's about one fatality a year, often people cleaning
fermenting vessels in breweries. That said, I did some measurements and
"calcs" for my local small brewery (Uley) which is in Victorian premises and
managed to convince the Health & Safety inspector that the natural
ventilation meant there was no risk in the cellar and that they therefore
didn't need multiple linked detectors.

On Fri, 17 Aug 2007 23:02:04 +0000, Shaun Van Poecke wrote:

Ive never actually breathed Co2 myself, though i have done my share of
confined spaces welding. Im very concerned about following the right
procedures for this type of work.


I'd think if it was that concentrated, your mucus membranes would let you
know RIGHT NOW, from the tingling, burning sensation as it dissolves
in the moisture and turns to carbonic acid. I've accidentally sniffed
"concentrated" CO2, and it was pretty obvious, and not pleasant at all.

Thanks,
Rich

On Sat, 18 Aug 2007 14:12:03 -0400, Bob Engelhardt wrote:
Shaun Van Poecke wrote:
... The cyllinder ruptured in
an unusual way, splitting right down the side. ... the safety release valve
did not operate, ...

... the Co2 filled up the copper pot ... the welder climbed into the pot
... once he was
inside the pot he was overcome pretty quickly by dizziness and was unable to
get out. ...

Shaun - thanks for the real-world input. Too many of our posts are
speculation, sometimes not based on much knowledge.

While accepting that CO2 is more dangerous than I believed, I'm still
going to store my cylinder in the cellar. It's a probability thing
(like most things in life). The probability that there'll be a fire AND
the safety will fail is small enough for me. Likewise the probability
that my cylinder will leak fast enough to fill up my drafty basement is
small enough. It's a small cylinder.

I don't think drafts will help that much, since CO2 sinks in air. But,
you'd get an early warning when your pilot lights went out. ;-)

Cheers!
Rich

Bob Engelhardt wrote:

Shaun Van Poecke wrote:
... The cyllinder ruptured in
an unusual way, splitting right down the side. ... the safety release valve
did not operate, ...

... the Co2 filled up the copper pot ... the welder climbed into the pot
... once he was
inside the pot he was overcome pretty quickly by dizziness and was unable to
get out. ...

Shaun - thanks for the real-world input. Too many of our posts are
speculation, sometimes not based on much knowledge.

While accepting that CO2 is more dangerous than I believed, I'm still
going to store my cylinder in the cellar. It's a probability thing
(like most things in life). The probability that there'll be a fire AND
the safety will fail is small enough for me. Likewise the probability
that my cylinder will leak fast enough to fill up my drafty basement is
small enough. It's a small cylinder.

Bob

It's pretty easy to figure out how much breathable air a leaking
cylinder could displace at atmospheric pressure, since that's typically
the cylinder spec for most gasses (CO2 an exception).

An 80cf Argon cylinder for TIG could at most displace 80cf of breathable
air, or less than a foot off the floor even in a small ~10'x10' shop.
Basically, a single home sized cylinder of inert gas completely emptying
in a typical home size shop couldn't pose a threat to a human, though it
could be a problem for your shop cat.

In a house fire it is very likely that you would be out of the house
long before a cylinder with a defective safety or no safety got hot
enough to potentially fail catastrophically.

Basically under normal home shop conditions you only have to worry about
flammable gasses and oxygen, anything inert just can't realistically
pose a safety hazard.

Pete C.

Dave Hinz wrote:

On Sat, 18 Aug 2007 11:07:43 -0700, wrote:
On Aug 17, 4:38 pm, "Pete C." wrote:

...

SCUBA tanks are a lot higher pressure than CO2. The only real issue with
CO2 is the potential for frostbite if you manage to release it in liquid
form on yourself. Just download the MSDS from the Airgas site.

I recall the air tanks were around 3000 PSI and gather that co2 is
somewhere
around the 600 mark.

Our SCBA tanks are pressurized up to 2215PSI. I have no idea where that
number comes from. There are also 6000PSI tanks I seem to recall
but...in a fire, one 2215PSI tank is all I can go through without being
tired, not sure how much longer the 6000PSI would last but, longer than
me.

Aluminum SCUBA tanks are usually 3,000PSI, some are 3,300PSI. Steel
SCUBA tanks are usually 2215PSI, though there are some HP versions. I've
seen composite SCUBA tanks that run at 4,500PSI and that is also a
common pressure for fire fighting SCBA tanks.

The 2215PSI SCBA tanks are typically older ones from what I've seen and
seen to be going away. I've not seen any portable SCUBA or SCBA tanks
running at 6,000PSI, but cascade tank banks often operate that high so
that they can fully fill the 3,000PSI tanks for a sizable draw down
before the compressor needs to operate again.

Pete C.

wrote:

On Aug 17, 5:03 pm, "Karl Townsend"
wrote:

...


Did you get one for paintball filling or for welding?

I don't plan to do any paintball. It's more for combat robotics. But I
would assume
that. from a procedure point of view, this would be like paintball.

The tank I have is for paintball and has a siphon.

the paintball unit has
a tube inside the tank so liquid comes out when its upright, can't be used
to weld. A weld tank has to be upside down to dispense liquid.

Does securing the tank upside down make any sense?


a small tube and valve kit is sold to hook the paintball tank up to the big
tank. Comes with directions. basically you vent a little gas out of the
paintball can and the pressure difference forces liquid across. Biggest
issue with filling is freezing a line up - go slow.

I've got a small tube like that. Made by Pure Energy. Didn't get any
instructions.
But it wasn't too hard to figure out.

I was able to use it to "fill" a 9 oz tank but don't have a scale to
check the
wieght.


DON'T OVERFILL. You need 20% headspace. Use a scale. "The kid" filled
paintball tanks for all his friends when he was home. He overfilled one and,
not knowing of a problem, put it in the car and started driving. It popped
the relief valve with a bang while they were driving. They almost had an
accident trying to jump out of the car cause they thought a bomb had went
off.

When you say don't overfill I assume you mean that there shouldn't be
too much
liquid in a tank?

Thanks,
DOC


A decent digital food or postal scale would be a good investment.

Pete C. wrote:
wrote:
Just got myself a co2 tank designed to fill small paintball tanks.

I plan to use this mostly for combat robotics and possibly
for a MIG set up when I get MIG.

I do have SCUBA experience, an air compressor and a TIG set up. But
co2 seems to be a bit of a different horse as it is stored in liquid
form.

Looking for information sources on handling this safely.
Favorite books, web sites, free advice...

Tanks :-) for any help.

DOC

SCUBA tanks are a lot higher pressure than CO2. The only real issue with
CO2 is the potential for frostbite if you manage to release it in liquid
form on yourself. Just download the MSDS from the Airgas site.

The bulk tank itself should require no more
care than your other high pressure bottles.

I understand that care is required in filling
the small paintball tanks to insure there's
always an adequate gas headspace above the
liquid. If not, heat can cause the liquid
to expand and explode the tank.

Does securing the tank upside down make any sense?
You don't need to, you got the one for filling tanks. But you can't weld
with this tank.

When you say don't overfill I assume you mean that there shouldn't be
too much
liquid in a tank?

Correct. If you put too much in you're going to pop something when
everything warms back up from the filling process. Buy a scale, eBay is your
friend here.

Karl

wrote:
Just got myself a co2 tank designed to fill small paintball tanks.

I plan to use this mostly for combat robotics and possibly
for a MIG set up when I get MIG.

I do have SCUBA experience, an air compressor and a TIG set up. But
co2 seems to be a bit of a different horse as it is stored in liquid
form.

Looking for information sources on handling this safely.
Favorite books, web sites, free advice...


Tanks :-) for any help.

DOC


Weigh the tank on an accurate scale while it is empty. Add the rated
capacity to that weight and that will be the maximum that the tank
should ever weigh after a fill.

If you find you have overfilled, no biggie, (other than it being a
waste) just bleed off some CO2 untill you are at the weight desired.

If you do not bleed a bit of CO2 off the tank (recieving) prior to
filling, or you do not place the tank into a freezer or on ice, it
"usually" (!!!) will not take a full charge, as the difference in
pressure is not great enough to flow enough liquid to get a rated fill.
Usually!

Most often, to get a full load on a paintball cylinder, you must
either be doing several at a time (which will load the siphon tube with
liquid) or you must give the tank a squirt, bleed it off (which chills
the tank) then fill it.

A digital scale that you can zero easilly will allow you to weigh the
fill, by zeroing with the empty cylinder on the scale, then weighing the
filled one, to see how much you got.

For personal use, I do not worry about getting right to the rated cap.
If I am paying by the rated cap. of the tank for a fill, I want to get
all the ounces I pay for.

FWIW, a pressure gauge is only really useful as an indicator that you
no longer have liquid CO2 in your tank and are running on gas pressure only.

Somewhere out there on the web is a US Navy chart that shows the
pressure-temperature relationship on a CO2 cylinder, including the
curves for overfills. Normal pressure is pretty steady at around 800 psi
(varies with temperature) but an overfill along with some heat can drive
the pressure WAY up WAY fast!

Overall I'd rate the risk of having a CO2 tank around as less than the
risks posed by the propane tank on the BBQ.

Cheers
Trevor Jones

On Sat, 18 Aug 2007 14:12:03 -0400, Bob Engelhardt
wrote:

Shaun Van Poecke wrote:
... The cyllinder ruptured in
an unusual way, splitting right down the side. ... the safety release valve
did not operate, ...

... the Co2 filled up the copper pot ... the welder climbed into the pot
... once he was
inside the pot he was overcome pretty quickly by dizziness and was unable to
get out. ...

Shaun - thanks for the real-world input. Too many of our posts are
speculation, sometimes not based on much knowledge.

While accepting that CO2 is more dangerous than I believed, I'm still
going to store my cylinder in the cellar. It's a probability thing
(like most things in life). The probability that there'll be a fire AND
the safety will fail is small enough for me. Likewise the probability
that my cylinder will leak fast enough to fill up my drafty basement is
small enough. It's a small cylinder.

Bob

Wouldn't worry about it for the normal 5-pound or 10-pound CO2
cylinder you'd have for home shop use - you can't flood a room that
well unless it's a full-size 50-pound tall bottle with several hundred
CF of gas inside and a really small basement.

Oh, and it may not be a pop-type resetting relief valve, they use a
rupture disc relief on some cylinders, once it pops it fully vents.
Ask the supplier what you have on any particular bottle.

As that fire proved, even if the cylinder relief valve vents, it may
not vent fast enough to prevent cylinder rupture in a fire. But I'll
bet there was a time delay between venting and popping, and everyone
had a chance to get out of the way.

-- Bruce --

Bob Engelhardt writes:

It's the rise in CO2 concentration
in our lungs that makes it so hard to hold your breath for very long.
There's still plenty of oxygen in your lungs but the rising CO2 says:
BREATH! BREATH!!

CO2 is not just an inert oxygen-displacing gas like other shielding gases
or fuels. Respiration takes O2 in and sends CO2 out. Too little pO2 or too
much pCO2 in the ambient will kill you, either one. Yes, CO2 is a sensible
respiratory stimulant in low concentrations, and not toxic in the sense
that it is something your body produces and a strong whiff will not hurt
you. But even with enough pO2 it doesn't take much pCO2 in the ambient air
to prevent you from clearing CO2 from the blood and getting very
distressed, even if the rest is pure O2.

Rich Grise wrote:
On Sat, 18 Aug 2007 14:12:03 -0400, Bob Engelhardt wrote:
Shaun Van Poecke wrote:
... The cyllinder ruptured in
an unusual way, splitting right down the side. ... the safety release valve
did not operate, ...

... the Co2 filled up the copper pot ... the welder climbed into the pot
... once he was
inside the pot he was overcome pretty quickly by dizziness and was unable to
get out. ...
Shaun - thanks for the real-world input. Too many of our posts are
speculation, sometimes not based on much knowledge.

While accepting that CO2 is more dangerous than I believed, I'm still
going to store my cylinder in the cellar. It's a probability thing
(like most things in life). The probability that there'll be a fire AND
the safety will fail is small enough for me. Likewise the probability
that my cylinder will leak fast enough to fill up my drafty basement is
small enough. It's a small cylinder.

I don't think drafts will help that much, since CO2 sinks in air. But,
you'd get an early warning when your pilot lights went out. ;-)

Or when the furnace comes on and starts pumping out CO..

John

Cheers!
Rich