Oh really? I thought it would be alot more than that. I will have to check with lake welding across the street from work and see what all it would take. Would be badazz if it can be switched over and filled for a good price.
CK5
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Scuba tank for off road?
- Thread starter andyblack
- Start date
Oh really? I thought it would be alot more than that. I will have to check with lake welding across the street from work and see what all it would take. Would be badazz if it can be switched over and filled for a good price.
Folks, let me jump in here for a minute. I worked for years with CO2 tanks. And did some compressed air work and helped slightly with SCUBA.
Compressed air tanks are just that. Tanks filled with air that has had the hell squeezed out of it.
The pressure in a tank like that will stay pretty much the same with normal temp ranges.
It will increase some with higher temps, but not as much as CO2.
A CO2 tank on the other hand has liquid CO2 in it instead of just compressed gas.
And for any of you chemistry majors out there, I know that CO2 does not have a liquid phase at normal pressure/temp, but it behaves like a liquid in this case, so close enough.
With compressed air, as soon as you start releasing it, the pressure starts to drop. With CO2, the liquid starts to boil. Of course, the tank gets cold, but if it were maintained at a constant temp, then the pressure would stay the same until all the liquid had boiled away.
Since any liquid is the equivalent of a huge amount of gas, then CO2 would be the way to go.
Think about how much steam you can get out of a small amount of water.
And CO2 can have less pressure than compressed air. But that pressure changes more with temp.
The books say that at room temp, a CO2 tank should have around 800 psia. But when I was working with it, I often saw pressures above 1K.
This is a lot less than what you get in a SCUBA tank, but since its liquified, you will get a ton more volume.
Now for the bad news.
Don't know if you said, but if that tank is aluminum, then it needs to be eddy current tested after a certain number of fill ups due to micro stress cracks that can develop.
I don't know the reg, but a SCUBA refiller will require it after every certain number of refills.
They really hate explosions in their fill stations.
Steel tanks need to be hydrostatically tested after every so many fillups.
How many times has yours been filled??
Also, you might look again at that label that says "air only"
Might be a clue that the maker did not think it was a good idea to put something else in it.
CO2 and moisture forms Carbonic acid. So, you need to be sure that the tank is dry especially if its aluminum.
Remember I said that since it has a liquid in it that pressure in a CO2 tank changes more with temp?
The valve on a CO2 tank has a rupture disk built in. Its a piece of copper about the size of a penny that will blow out before the tank does if it gets too hot.
If you put any kind of valve on that tank, it needs something like that built in.
One other thing you have to watch out for.
A SCUBA tank being filed with air is just pumped into until the pressure reaches a certain point, or the weight of the tank reaches a certain point.
If you put in a little more, than the pressure just gets a little higher.
CO2 don't work that way.
Since you are, in effect, pouring in a liquid. The pressure will stay pretty much the same until the tank is completely full.
At which point, you have a bomb waiting to go off.
CO2 tanks are always filled by weight.
Liquid is not compressible. You have to have some space in the tank to allow for expansion with temp.
All CO2 tanks have the empty and full weight stamped on them, or some way to determine it.
Your SCUBA tank may not have.
Several years ago, we had a mix of aluminum and steel CO2 tanks. Our filler let a new guy fill a bunch of them.
He started on the steel tanks. Put one on the scales, zeroed it, and set it to trip at 20 pounds since that was the size tanks he was filling.
Then, after a few, he grabbed some aluminum tanks.
Did not rezero the scales.
Proceeded to fill them all the way to the top.
Thank God for rupture disks. The tanks started venting all over town. I went in to the store room and saw 4 spinning on the concrete at the same time.
We evacuated the place and told the company to come get their tanks.
As for your tank. If you get it tested, and make sure that any valve you use has a rupture disk, and that its dry, then it might be safe to use.
Personally I would not do it. But, I have seen tanks explode. And I am sure that there are thousands of folks using old SCUBA tanks and have had no problems.
I have watched people scratch their ears with loaded rifle barrels too........
CO2 runs at a lot lower pressure than SCUBA, which is why people use those tanks for CO2 after they are no longer rated for compressed air.
CO2 tanks will explode with less force than a filled SCUBA. But if it does so in your vehicle while you are in it, then its pretty much a moot point.
Its like the difference between being shot in the head by a .38 or a 12 gauge.
Its only a concern to the funeral makeup guy.
BTW, a compressed air tank can be run at any position. CO2 must be run with the valve up.
You DO NOT want liquid CO2 in your system or tire.
Here is an example of a SCUBA tank that failed in the trunk of a car. Do a search for other pics. There are plenty of them out there.
Compressed air tanks are just that. Tanks filled with air that has had the hell squeezed out of it.
The pressure in a tank like that will stay pretty much the same with normal temp ranges.
It will increase some with higher temps, but not as much as CO2.
A CO2 tank on the other hand has liquid CO2 in it instead of just compressed gas.
And for any of you chemistry majors out there, I know that CO2 does not have a liquid phase at normal pressure/temp, but it behaves like a liquid in this case, so close enough.
With compressed air, as soon as you start releasing it, the pressure starts to drop. With CO2, the liquid starts to boil. Of course, the tank gets cold, but if it were maintained at a constant temp, then the pressure would stay the same until all the liquid had boiled away.
Since any liquid is the equivalent of a huge amount of gas, then CO2 would be the way to go.
Think about how much steam you can get out of a small amount of water.
And CO2 can have less pressure than compressed air. But that pressure changes more with temp.
The books say that at room temp, a CO2 tank should have around 800 psia. But when I was working with it, I often saw pressures above 1K.
This is a lot less than what you get in a SCUBA tank, but since its liquified, you will get a ton more volume.
Now for the bad news.
Don't know if you said, but if that tank is aluminum, then it needs to be eddy current tested after a certain number of fill ups due to micro stress cracks that can develop.
I don't know the reg, but a SCUBA refiller will require it after every certain number of refills.
They really hate explosions in their fill stations.
Steel tanks need to be hydrostatically tested after every so many fillups.
How many times has yours been filled??
Also, you might look again at that label that says "air only"
Might be a clue that the maker did not think it was a good idea to put something else in it.
CO2 and moisture forms Carbonic acid. So, you need to be sure that the tank is dry especially if its aluminum.
Remember I said that since it has a liquid in it that pressure in a CO2 tank changes more with temp?
The valve on a CO2 tank has a rupture disk built in. Its a piece of copper about the size of a penny that will blow out before the tank does if it gets too hot.
If you put any kind of valve on that tank, it needs something like that built in.
One other thing you have to watch out for.
A SCUBA tank being filed with air is just pumped into until the pressure reaches a certain point, or the weight of the tank reaches a certain point.
If you put in a little more, than the pressure just gets a little higher.
CO2 don't work that way.
Since you are, in effect, pouring in a liquid. The pressure will stay pretty much the same until the tank is completely full.
At which point, you have a bomb waiting to go off.
CO2 tanks are always filled by weight.
Liquid is not compressible. You have to have some space in the tank to allow for expansion with temp.
All CO2 tanks have the empty and full weight stamped on them, or some way to determine it.
Your SCUBA tank may not have.
Several years ago, we had a mix of aluminum and steel CO2 tanks. Our filler let a new guy fill a bunch of them.
He started on the steel tanks. Put one on the scales, zeroed it, and set it to trip at 20 pounds since that was the size tanks he was filling.
Then, after a few, he grabbed some aluminum tanks.
Did not rezero the scales.
Proceeded to fill them all the way to the top.
Thank God for rupture disks. The tanks started venting all over town. I went in to the store room and saw 4 spinning on the concrete at the same time.
We evacuated the place and told the company to come get their tanks.
As for your tank. If you get it tested, and make sure that any valve you use has a rupture disk, and that its dry, then it might be safe to use.
Personally I would not do it. But, I have seen tanks explode. And I am sure that there are thousands of folks using old SCUBA tanks and have had no problems.
I have watched people scratch their ears with loaded rifle barrels too........
CO2 runs at a lot lower pressure than SCUBA, which is why people use those tanks for CO2 after they are no longer rated for compressed air.
CO2 tanks will explode with less force than a filled SCUBA. But if it does so in your vehicle while you are in it, then its pretty much a moot point.
Its like the difference between being shot in the head by a .38 or a 12 gauge.
Its only a concern to the funeral makeup guy.
BTW, a compressed air tank can be run at any position. CO2 must be run with the valve up.
You DO NOT want liquid CO2 in your system or tire.
Here is an example of a SCUBA tank that failed in the trunk of a car. Do a search for other pics. There are plenty of them out there.
CO2 is also a deadly gas that if stored inside your vehicle and say you valve leaks then your car can fill with CO2 and kill you if you aren't careful!!
BTW nitrogen is way better to use in tires anyway, why not use that? It's lighter and doesn't expand/contract as much as air with temperature changes. Plus nitrogren isn't a poisonous gas so if it leaks in your car, oh well, fix leak and refill tank.
BTW nitrogen is way better to use in tires anyway, why not use that? It's lighter and doesn't expand/contract as much as air with temperature changes. Plus nitrogren isn't a poisonous gas so if it leaks in your car, oh well, fix leak and refill tank.
Not too worried as it will be mounted in my what would be bed of my rig.
CO2 is not poisonous. CO is. If CO2 were poisonous then we would all be dead since we have a large amount in our lungs all the time.
Plus inhaling the smell of a Coke would take you out.
Nitrogen has the same problem that compressed air does. Its just a compressed gas. CO2 turns into a liquid and a tank will hold many many times the volume that simple compressed gas will.
And at a lower pressure.
I don't do the airing down most folks here do, so I get by with a decent compressor. If I needed a tank, it would be CO2.
But, it would be a tank and system designed for CO2.
Plus inhaling the smell of a Coke would take you out.
Nitrogen has the same problem that compressed air does. Its just a compressed gas. CO2 turns into a liquid and a tank will hold many many times the volume that simple compressed gas will.
And at a lower pressure.
I don't do the airing down most folks here do, so I get by with a decent compressor. If I needed a tank, it would be CO2.
But, it would be a tank and system designed for CO2.
I said that wrong, CO2 isn't poisonous but it displaces oxygen. That's how it puts fires out. I guess its my background in the marine industry where its used in enclosed spaces such as fixed systems for engine rooms that will kill you if you in the space when its discharged.
Yep, it will definitely do that. I crawled into a cabinet to try to find a CO2 leak and found out it was worse than I thought.
My partner had to drag me out.
We opened the rest of the doors and put a fan in place before I went back in with the soapy water.
My partner had to drag me out.
We opened the rest of the doors and put a fan in place before I went back in with the soapy water.
Oh come on... a little hypoxic brain injury is good for ya. Builds character
Yeah, its a real shame. If you think I'm smart now, you should have known me before................
Yeah, its a real shame. If you think I'm smart now, you should have known me before................
unfathomable by all accounts
andyblack
Registered Loser
Okay, this is actually starting to sound like a majorly bad idea here. I think I would rather drive slow with aired down tires to the nearest gas station than risk an explosion with an old tank of questionable origin.
I think i will still try mine. It was a friend of my dads and he only bought it brand new for paintball but got out of it. I beleive you can see the rupture disk on the side (looks like a hex plug with a tiny hole in it i think). I will make sure to fasten it well and maybe put some type of rubber on and mounting surface to absorb vibrations.
If you know its history, then its not a bad bet as long as its history is good.
But a tank of unknown origin may not be worth the risk.
The companies that refill those things have testing procedures that they can use to re-certify a old tank.
Steel tanks can be inspected with a borescope, then hydrostatically tested. That test uses water pressurized to a higher pressure than it is expected to ever see.
Since water does not compress, if the tank ruptures, then there is no explosion, just a crack.
But, an aluminum tank can develop micro-fractures that will pass the pressure test, but will continue to grow with use and eventually the tank will fail
So they have to be tested with electrical eddy currents similar to magnafluxing a block or head.
All these can be done by a good refill place.
I don't know the cost, but it would seem to have to be less than a new tank.
I would never pressurize an unknown older tank without a test first.
But a tank of unknown origin may not be worth the risk.
The companies that refill those things have testing procedures that they can use to re-certify a old tank.
Steel tanks can be inspected with a borescope, then hydrostatically tested. That test uses water pressurized to a higher pressure than it is expected to ever see.
Since water does not compress, if the tank ruptures, then there is no explosion, just a crack.
But, an aluminum tank can develop micro-fractures that will pass the pressure test, but will continue to grow with use and eventually the tank will fail
So they have to be tested with electrical eddy currents similar to magnafluxing a block or head.
All these can be done by a good refill place.
I don't know the cost, but it would seem to have to be less than a new tank.
I would never pressurize an unknown older tank without a test first.
Thats almost a requirement at all the places. If it doesn't have their tag on it they will not fill it. Example, my welding bottle I can only fill at my welding place. I tried to fill it at airgas once to no avail. Same thing goes with my C02 tanks, which are stamped airgas. Tried to fill them at my welding place they said they would have to rectify them before they fill them. They then informed me that since the bottles had an airgas tag just take it to them no recertification needed, just the fill. Works for me even though I would rather go through the place I get all my welding gas from.
andyblack
Registered Loser
I just found a Alum 80 Scuba tank today. I need to call the local dive shop and check the tank stamps before I buy.
Let us know how it works out. I ended up getting rid of mine and not using it. It was taking up space and I needed to make some room, so it went bye-bye. I'd still like to know how well it would have worked though, just in case I ever run across a new one.
Kain
3/4 ton status
get it tested before you use it then you will know
palmerwerks
Newbie
Scuba tanks require a visual inspection every year,and hydro test every 5 years.use mine a lot for filling tires and running air tools.I also dive so if you have any other questions let me know.
andyblack
Registered Loser
Dude I wish you had joined about this time last year so I could find out some stuff.
I mean I just got rid of that tank a couple of weeks ago.So how many 35x12.50 tires can you air up with one 80lb. tank full? Say from 10 psi to 25 or 30 psi?
palmerwerks
Newbie
I have filled my 38in from 0to35 at least 4 or 5 times that also includes some air tool use.most shops fill steel tanks to 3000psi,setting one up is easy take the first stage reg and put air fitting on it.the first stage is around 120psi if I remember correctly.
