Oxygen tank

[Haniball1337]

Hi guys, i want to build air tank for my air rifle and i found olx oxygen tanks. They are from 1980 i think, and they are all little rusted not much . I'd like to pump it something about 100 bar, it will be safe to put that pressure in this tanks?

[jrrdw]

Depends on how badly they are rusted. I would fill the tank and a barrel with water and hydro test them. That's probably the safest way in the back yard.

[jackssmirkingrevenge]

I'd like to pump it something about 100 bar

What are they rated for? If I'm not mistaken Oxygen is typically run at around 170 bar. As jrrdw suggested, a hydrotest using fluid would not be a bad idea, not just for the tanks but for the rest of the setup, don't forget that your system is only as strong as your weakest fitting.

Here's a dude doing a DIY hydrotest, you can find similar guides online:

[youtube][/youtube]

[Haniball1337]

They are medical oxygen tank

[jackssmirkingrevenge]

There should be a pressure rating written somewhere around the neck.

[Haniball1337]

i think this is they rating and inside i dont see any rust its clear but another one have little rust. So can I fill one to about 200 bar or even this 250? they are really heavy

[D_Hall]

i think this is they rating and inside i dont see any rust its clear but another one have little rust. So can I fill one to about 200 bar or even this 250? they are really heavy

Looks like 250 is the rating but I'd be a bit leary if the rust is anything other than cosmetic. Do you know the history of the bottles?

[Haniball1337]

I only know they are from 1980 and they was using in medical ambulance. 1 bottle i think is in very good condition

[D_Hall]

I only know they are from 1980 and they was using in medical ambulance. 1 bottle i think is in very good condition

1980 is no big deal. In the compressed gas world, that's practically new! The question is how they've been stored and such. Again, rust is a concern. If they've been stored in a cool, dry place and just happen to have some cosmetic (read: surface) rust? No big deal. If they were pulled up from the bottom of a Florida swamp, on the other hand....

[Haniball1337]

I think 1 bottle was using in underground mining safety equipment. They was stored in a dry and warm room. Yeah, i have another problem. I can't find any thread that will be compatible. I tried 1/2 and 3/8 and 1/2 is little big for it , and 3/8 is screwing on but only at end of bottle thread, i think its tapered thread. How can I find out thread of this bottle? I was looking at bottle but there is many numbers.

[Haniball1337]

Will 3/8 tapered thread nipple be compatible with bottle? or something different? i tried 1/2 tapered thread pipe and it screw but only 2 (tooths?)

[farcticox1]

Might be NPT vs BSP although 1/2" is pretty close, both 14 TPI

93176bfa17fb8a40841bd9a8f8d5ab.jpg (16.63 KiB) Viewed 7155 times

[Haniball1337]

So i need to buy NPT thread reduction or BSP Thread right?
I found NPT 3000 psi nipple it has NTP thread, and i found G1/2'' x 3/8 reduction nipple and it has GZ BSPT 1/2' x GZ BSPT 3/8'' thread. Both nipples are 3/8 threads. Or i need 1/2? .Will this do a job?

[mrfoo]

No, what you need is one of these

[Haniball1337]

Will this be good?