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Re: Oxygen tank

Unread postPosted: Fri Jul 05, 2019 2:23 pm
Author: Haniball1337
I have another question. Will this steel tee and ball valve hold 200 bar pressure? Steel Tee has pressure rating to 25 bar. Brass ball valve has 30 bar rating.

Re: Oxygen tank

Unread postPosted: Sat Jul 06, 2019 1:07 am
Author: mrfoo
Q: Will this pipe fitting handle 10 times its rated pressure, in an application close to my head?
A: Have you heard of the Darwin Awards?

Re: Oxygen tank

Unread postPosted: Sat Jul 06, 2019 3:30 am
Author: Haniball1337
So it wont be able to hold that? I found that Joerg Sprave was using ball valve rated to 150 psi and it was able to hold 200 bar.

Re: Oxygen tank

Unread postPosted: Sat Jul 06, 2019 11:04 am
Author: mrfoo
It might hold. It might not. It's the "not" case that is worrying. If something lets go, things will get ugly very fast. Think "fragmentation grenade". I've seen the results of a small worksite compressor tank (luckily, there was nobody nearby) that failed at 8 bar, it tore the back out of the van.

If you're dealing with stored gases, rather than incompressible fluids, your safety factors need to be significantly higher. In this very thread, you were worrying about the pressure rating on a bottle that's designed for high pressure gas storage, but will happily go ten times higher than the maximum "safe" rating on fittings when high pressure rated fittings and valves exist. They're almost certainly more expensive, and difficult to get "over the counter" - you may need to find a specialist supplie - but you'll be working within the design parameters of the components rather than trusting to blind luck.

Re: Oxygen tank

Unread postPosted: Sat Jul 06, 2019 2:01 pm
Author: Haniball1337
You're right. I think i will buy high pressure rated fittings because i dont want risk. I even found that 250+ bar rated tee costs less than this 25 bar rated tee... How about 3000 psi rated aluminum paintball tank Can i take it to 300 bar?

Re: Oxygen tank

Unread postPosted: Sat Jul 06, 2019 2:22 pm
Author: jackssmirkingrevenge
I've used that style of ball valve at 55 bar, but that was at my own risk, I wouldn't recommend it.

How about 3000 psi rated aluminum paintball tank Can i take it to 300 bar?


The safety disk on 3000 psi compressed air paintball tanks typically blows at 5000 psi or around 340 bar, but that doesn't mean you should be pushing it that far. There are carbon fiber tanks that are rated for 300 bar.

Re: Oxygen tank

Unread postPosted: Sat Jul 06, 2019 2:48 pm
Author: Haniball1337
Ok thanks for info

Re: Oxygen tank

Unread postPosted: Sat Jul 06, 2019 11:11 pm
Author: D_Hall
jackssmirkingrevenge wrote:I've used that style of ball valve at 55 bar, but that was at my own risk, I wouldn't recommend it.

How about 3000 psi rated aluminum paintball tank Can i take it to 300 bar?


The safety disk on 3000 psi compressed air paintball tanks typically blows at 5000 psi or around 340 bar, but that doesn't mean you should be pushing it that far. There are carbon fiber tanks that are rated for 300 bar.


typically an "aluminum paintball tank rated to 3000 psi" is actually a CO2 tank. Working pressure is approximately 850 psi but they're made to go much higher (3k, obviously) because a full CO2 tank's pressure can vary wildly if slightly over filled and put in a warm environment. And they have 3k burst disks.

Re: Oxygen tank

Unread postPosted: Sun Jul 07, 2019 1:41 am
Author: Moonbogg
You guys are talking about some insane pressure. I think my last cannon is at least fairly beefy (at least I hope it is) and I'm still afraid of the thing at what should be around 300psi max. Maybe I'm just ignorant, a chicken, or both, but I'd never use something at 3000psi unless it was designed for it, labeled for it and according to manufacturer instructions exactly.
The reason for my anxiety is because every cannon is a one-off creation. Without the resources to test several identical cannons to failure under varying circumstances, I will always have a healthy dose of anxiety.
300 bar is insane pressure. Please don't kill yourself dude.

Regarding the valve question. I took a small brass needle valve to 450psi and it was rated for I think 200 or something like that, and it leaked at 450psi. Even if the valve doesn't explode (which it might) it is still likely to leak at such a high pressure. I don't know if those seals are designed for 10X their suggested pressure. Also, with air pressure that high, can't the thing explode if even a little oil or other contaminants get on the threads? Scary as HELL!

Re: Oxygen tank

Unread postPosted: Sun Jul 07, 2019 5:11 am
Author: Haniball1337
Nevermind i think i will not use ball valve. I just found a pcp one way filling valve for 10$. Something like this

Re: Oxygen tank

Unread postPosted: Sun Jul 07, 2019 2:22 pm
Author: D_Hall
Moonbogg wrote: Maybe I'm just ignorant, a chicken, or both, but I'd never use something at 3000psi unless it was designed for it, labeled for it and according to manufacturer instructions exactly.


Not chicken. Maybe a tiny bit ignorant if by "ignorant" you simply mean, "not a professional in the field of compressed gases." For the vast majority of folks, the word you're looking for is "smart".

Have I exceeded manufacturer specs? Yes, but not grossly and at the risk of sounding like an arrogant asshat, I *am* a professional in this case. Those times I exceed the specs? I don't do it willy-nilly. I reverse engineer the design to see what's driving the performance of the gizmo.

Re: Oxygen tank

Unread postPosted: Sun Jul 07, 2019 6:14 pm
Author: Moonbogg
D_Hall wrote:
Moonbogg wrote: Maybe I'm just ignorant, a chicken, or both, but I'd never use something at 3000psi unless it was designed for it, labeled for it and according to manufacturer instructions exactly.


Not chicken. Maybe a tiny bit ignorant if by "ignorant" you simply mean, "not a professional in the field of compressed gases." For the vast majority of folks, the word you're looking for is "smart".

Have I exceeded manufacturer specs? Yes, but not grossly and at the risk of sounding like an arrogant asshat, I *am* a professional in this case. Those times I exceed the specs? I don't do it willy-nilly. I reverse engineer the design to see what's driving the performance of the gizmo.


They say knowledge is the antidote to fear, and I do lack many knowledges, therefore I experience many fears :lol: I think my comfort zone is pretty conservative compared to the OP's. That's the reason I was expressing fear for the OP. Many fears, actually.

Re: Oxygen tank

Unread postPosted: Fri Jul 12, 2019 8:19 am
Author: Haniball1337
I have paintball bottle which has PH 300 bar and there is on bottle tap about thread size. It say 5/8 18 UNF. I tried 5/8 thread and it's too big for it. bottle only fits 3/8 but for 2 tooths.
Photo: https://imagizer.imageshack.com/img924/3833/lvWNJ7.jpg
I look on internet for 5/8 - 18 UNF and i found reduction from this 5/8 - 18 UNF to 1/4 BSP i think it will fit or I am wrong?