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Score of the day 6.8liter 300bar CF bottles

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Chickenthief

Chickenthief

Member
Aug 16, 2019
820
153
Intoxicated, Denmark
I found this advert for a 6.8liter 300bar CF bottle with DIN300 fitting for @ $80 including shipping (In Denmark!!!), really nice looking.

Yeah they expired in 2020 but with my own compressor and booster i'll live fine ;-)

I bought one and asked if maybe he could get more, ansver; I got 15 more in stock how many do you want?

So i bought another 5 and think i'm good for the forseeable future :)



Talk about being in the right place at the right time. Wont see that again ever?
 
The reason they are cheap is cause they are expired. No shop will fill them or even hydro test them. Very dangerous to be filling a out of date tank even if you own your compressor. They have a life cycle for a reason. They hydro test every 5 years for a reason. If you cant hydro test. How will you know its good. You do not wanna know what a 300bar cr tank looks like when it goes kaboom. My life ain't worth saving a few bucks on a expired tank. Thats my 2 cent.
 
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The reason they are cheap is cause they are expired. No shop will fill them or even hydro test them. Very dangerous to be filling a out of date tank even if you own your compressor. They have a life cycle for a reason. They hydro test every 5 years for a reason. If you cant hydro test. How will you know its good. You do not wanna know what a 300bar cr tank looks like when it goes kaboom. My life ain't worth saving a few bucks on a expired tank. Thats my 2 cent.
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Well, that was the exact same response on a Danish forum for airgunners and I very much agree 👍 Way to dangerous to play aroud with !!
 
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The reason they are cheap is cause they are expired. No shop will fill them or even hydro test them. Very dangerous to be filling a out of date tank even if you own your compressor. They have a life cycle for a reason. They hydro test every 5 years for a reason. If you cant hydro test. How will you know its good. You do not wanna know what a 300bar cr tank looks like when it goes kaboom. My life ain't worth saving a few bucks on a expired tank. Thats my 2 cent.
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Well, that was the exact same response on a Danish forum for airgunners and I very much agree 👍 Way to dangerous to play aroud with !!
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Agree. None for me, thanks.
 
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So my seventeen year old 106 cubic foot carbon fiber wrapped tank that I bought new, has no nicks, dents or even scuff marks and has sat in a corner except for being filled occasionally is a danger solely because some government agency said it had a fifteen year life span and would expire in 2019?


I actually had its last hydro test approved the week of its expiration date and had it filled, at an airgun store, on the very last day of its life span. The airgun store told me they would not have filled it the next day because of regulations but since it was the last day of the month in which it expired, it was safe to fill.


When I drew that tank down I was faced with a decision on whether to abandon the tank and spend approximately $700 for a new one or apply that amount towards a compressor and keep on truckin’. You can guess what I did....

BTW, the same tank that has a fifteen year lifespan in the USA has a 30 year lifespan in Europe. Guess they’re not very safe over there.
 
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I was under the impression DOT limits them to 15 in USA.

I had heard in Europe 30 years.

I bought a big Alkin because I don't mind filling to only 3K. Why would I care when I shoot tethered & take Regs out. I run guns at lower pressures because you can start to really tune the harmonics out and variance of reservoir flex. 
My cyclic pressure is 2-3K, no need to go to 4500 when you have endless air. The slug shooters produce more power on lower 2050-2150 pressures anyway. I can't compete tethered or not so I might as well simplify things when going long. Otherwise 10m .177's are just as much fun for me.
 
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I should note that we trade risk for money all the time, every day. You could get bigger vehicles and be statistically safer in motor vehicle accidents, but it's more expensive. You could get more medical examinations and tests done to catch diseases earlier, but it's more expensive. In these and countless other similar examples you are left to evaluate the risks and the costs. Using HPA is one of those situations- you have to make the determination for yourself.
 
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I got a Scott air tank from ebay that was recently expired. I used a snake camera to look inside for any deformations and then hydrotested it myself at 6000 psi. I also measured the circumference of the tank under the water and saw that it wasn't getting any bigger. Honestly I know that's not the exact procedure to hydrotest and that I'm taking a chance. However I think it's a very low chance of it exploding. Maybe I'm not being wise but I'm happy with my Scott pack and really happy that I saved all that money. I also use it to fill my 2000 psi airguns and only fill it to 3500. I see nothing wrong with saving some money. I get that is a touchy subject for some people and I get it. I don't suggest new airgun owners skimp on saftey to save money but if you know what your looking for and examine the tanks inside and out I just don't see it being a problem. 
 
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I watched a video of a fiber wrapped, pressurized tank, shot at, and the first shots didn’t penetrate the tank, and it didn’t burst. When it was shot and penetrated, it still didn’t burst. It appears to me that a carbon fiber tank catastrophic failure is a truly rare event, and most tank failures are leaks through the fiber capsule when the liner tank fails in some fashion, I have seen discussions about that very failure, zero burst tank discussions.
 
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I watched a video of a fiber wrapped, pressurized tank, shot at, and the first shots didn’t penetrate the tank, and it didn’t burst. When it was shot and penetrated, it still didn’t burst. It appears to me that a carbon fiber tank catastrophic failure is a truly rare event, and most tank failures are leaks through the fiber capsule when the liner tank fails in some fashion, I have seen discussions about that very failure, zero burst tank discussions.
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Yeah you watching a video of .22lr plinker guy shooting a paintball tank with a airforce. We all seen that. These tanks are tough, yes. But over time they will wear out and deform and get weaker. You think 4500 psi behind a tank, it will leak out of the fiber? Lol. Dude you have no idea. When these things go kaboom. Its like a freaking bomb. It will tear your skin off your meat and bones like nothing. If you think its worth it, go right on ahead. I aint putting my life or any of my family life on the line. These hpa are very dangerous.

Skip to 2:05. The professional hydro testing these tanks for years can give you some important information. Rather than just having random folks on a forum tell you.

http://m.youtube.com/watch?v=AlFWTcgjhl8&t=153s
 
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You are probably right that you won't see that again, ever. I'm surprised that it is even legal to sell an expired pressure vessel that hasn't been rendered inoperable. What you have are $80 second-hand valves. I'm not saying that the tanks aren't safe just that they are out of date so technically out of service so therefore have no monetary value. It's a bit like an out-of-date loaf of bread, it may be still edible but it is illegal for a vendor to sell for human consumption. I also think that reports of European laws allowing 30-year life spans on the same bottles as the US ones have been misrepresented. Every country has its own regulations, there may be some that allow longer life spans but they may also have a more rigorous testing regime. The DOT regulations are very conservative and in some ways haven't kept up with technology. For instance, 300 BAR steel SCUBA bottles are widely used in the rest of the world but DOT won't permit them for use in the US. The DOT laws for these bottles were drawn up when the CF bottle concept was quite new and there was little long-term data available to rely on. They also had to factor in the extremely harsh conditions that they would be subjected to and how many cycles they could be safely put through in their lifetime. All this means is that the bottles are over-engineered and with the right treatment are probably indestructible but with a bit of mistreatment like allowing moisture to contaminate the inner surface, they may be unsafe no matter what the external surface looks like.
 
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I know that I ain't that smart and I am not trying to argue with anyone. I know HPA is dangerous in any form. It is a given fact.

However the concept that a tank that is safe today has a birthday and now it is no longer safe is beyond me.

Everything you do has risk. By the numbers getting in to a car is the most dangerous thing one can do but we take the risk.

God Bless

Bobby
 
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I know that I ain't that smart and I am not trying to argue with anyone. I know HPA is dangerous in any form. It is a given fact.

However the concept that a tank that is safe today has a birthday and now it is no longer safe is beyond me.

Everything you do has risk. By the numbers getting in to a car is the most dangerous thing one can do but we take the risk.

God Bless

Bobby
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I see the point both sides of this discussion are making. I'd like to answer Bullet Bob's question regarding why does a tank become scrap after 15 years.

Most of the used SCBA tanks on Ebay are surplus sales of heavily used firefighter's equipment. The 15 year life span has more to do with the abuse that a firefighting tank receives. That comes from two things. One is the number of times a tank is filled and second it the amount of damage caused to the outer shell by service wear and tear and the aging of the coating. Firefighter SCBA tanks typically have many many times the refills in service duty than an airgunner. Think of the aluminum inner liner as a lung. The aluminum at 4500 psi flexes out more than at 0 psi. Firefighters use the entire 4500 so the flexing is more than an airgunner who refills his tanks when they refill at 2500 to 3000 psi. Our tanks are cycling fewer times and with less pressure flexing than in a fireman's tank. The aluminum develops stress fractures from pressure differential flexing and the outer shell becomes damaged from wear and tear and flexing cycles. 

Think of it this way. A 15 year old car that has been garage kept with 2,000 miles on the odometer and that has been babied is in better shape than the same model after 2 years in a rental company fleet. We coddle our new tanks with coverings, cradles, and carry handles and don't leave them out in the yard in the sun. So a 15 year expiration is overkill for an airgunner's tank but important for a fireman's tank that has seen heavy service. More cycles, more flexing, and more wear and tear. 15 years may seem arbitrary, but it has to be set somewhere. 

I have my own compressor, and I don't hydro my tank nor pay for annual inspections. But I fill it with it with breathable quality air and don't abuse it so I don't spend money on hydro tests. My new tank will outlive me, but I'm an old fart anyway.
 
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