/diy/ - Do It Yourself

[OP No.556483]

I need to make a portable and relatively light container that can hold ~800 PSI of pressure inside with a valve to release it.
I was thinking of using sheet steel (no idea what gauge would be sufficient) to create a basic cone shape with rivets and then melting aluminum or copper over the seams to seal it.
What would /diy/ recommend?

[Anonymous No.556488]

You CANNOT make a safe high pressure vessel with rivets. That's absolutely retarded. I wouldn't even trust my own welding skill to make an 800psi container.
>>I need to make a portable and relatively light container that can hold ~800 PSI
Oxygen tank. Even the smaller ones can hold 2200PSI while weighing less than 3 pounds and costing less than $150.

[Anonymous No.556489]

What do you need 800 psi for ?

[OP No.556490]

>>556488
Sorry, my reasoning was that since old ships used rivets to keep their hulls airtight, I could do the same. In hindsight, I suppose the pressures are quite different.
Thank you for the suggestion of oxygen tanks. I hadn't even thought of that. I don't have much experience with them either. What sort of nozzle/adapter is used to fill them?

[Anonymous No.556498]

You could use a paintball HPA tank and a "bottom line" Regulator. An inline regulator will work as well but requires extra parts.
http://nerfhaven.com/forums/index.php?showtopic=8632

[Anonymous No.556653]

>>556483
You don't.
You get an oxygen tank like used for welding.
Then you explain what it is you need 800psi for, since that's dangerous as fuck pressure-wise.

[contractor No.556938]

I once saw a mostly empty oxygen tank EXPLODE through a steel fab shop, and it took a 5' section of steel panel wall with it.

Whatever you THINK you need 800 PSI for.... Don't.
Unless you are really experienced, don't fuck around with high pressure ANYTHING, especially since you've not said what you want it for.


Hell, I get antsy when making up new 200 PSI compressed air-tool lines.

[Anonymous No.556939]

I dunno how high of pressure the CO2 tanks go. Plus it is self-limiting due to the vaporization effect.

>>556653
>You get an oxygen tank like used for welding.
>Then you explain what it is you need 800psi for, since that's dangerous as fuck pressure-wise.
I don't know about other countries--but in the US, you could only get an oxygen tank filled with oxygen from a shop. They won't put anything else in it for safety reasons.

You could rent/lease tanks of "nitrogen" from welding shops, that goes up to 2000 PSI. Nitrogen would be safer than oxygen, plus it's cheaper also.

If you want "air" then the only option is scuba tanks, but most US scuba shops will only fill a tank if you have either 1) a current dive certificate, or 2) can show that you own a pneumatic air gun that you would use the tank for.

Continued in next post...

[Anonymous No.556941]

...Continued.
The little port-a-torch oxyacetylene kits use fuel/ox tanks that are 10/20 cu feet, respectively. The fuel tank is fairly thin and only filled to 300 PSI normally, but the oxygen tank is thick steel and normally filled to 2000 PSI. A few years ago the oxygen tanks cost about $80 empty.

BUT
you would need your own dive compressor to fill it, if you wanted refills with no questions asked. A dive compressor is maybe $1500.
AND
if you try to fill it with any other tank, the humidity in the air will rust the (steel) tank from the inside-out.... the dive compressors have a device that removes nearly all the humidity from the air before putting it into the tank.

If you need high-pressure gas for a short-term project, renting nitrogen tanks from a welding shop is probably the cheapest & easiest way.

[Anonymous No.556946]

>>556939
>I dunno how high of pressure the CO2 tanks go.

That 800 psi suggests that OP wants to use his tank for CO2.

[Anonymous No.557268]

Theres a reason you don't see riveted or seemed cylinders. it's because they don't work.you can get a small aluminium dive cylinder or pony bottle quite cheap and have this filled with whatever you want,you can also buy fibreglass cylinders these days that hold around 100 bar or you can try and get your hands on an old firemans cylinder, thats what i use when i require compressed gas. just be aware this shit requires testing, there is a reason its tested though, compressed gasses can cause a whole host of problems when not correctly maintained or stored. water ingress and damage is amplified when under compression and you will soon find yourself sponging up your loved ones bodily parts when it ruptures accidentally because you've let it run too low. why do you need 800 psi of pressure?by the looks of it you are quite inexpieranced using pressurised gasses so it begs the question of wtf you need it for.

[Anonymous No.557388]

>>556483
I recommend you mix some WD40 and coca cola, that should get you about 800 PSI.

Seriously, you're either a troll or a suicidal fuck up and I'm not going to play along. Whatever it is you're thinking about, you're too stupid to pull it off without people getting hurt.

[Anonymous No.557459]

OP still hasn't stated what he needs an 800 PSI tank for. That would wildly determine the advice given. Right off the bat, I'd suggest using CO2 tanks or HPA tanks for paintball. But for all we know, OP is trying to build a submarine or something.

[OP No.558283]

Basically I want to copy the technology used for the Girandoni Air Rifle. They used riveted metal containers with metal melted over the seams to contain about 800PSI of pressure, which I why I started there.
>inb4 "Fuck off to /k/!"
They don't have the sort of knowledge that I need, and gunsmithing is allowed on /diy/ according to the sticky

What's the upper limit for pressure on commonly available CO2 tanks for paintball/airsoft?

[Anonymous No.558300]

Paintball hpa tanks are 4500 psi, regulated to 800 output psi normally. Though you can get them with low pressure regulators.
I have two hpa paintball tanks for my gun. One is 3000 and the other is 4500 psi. Both 68 cubic inches.

[Anonymous No.558311]

>>556483
Scuba tanks are inexpensive.

There are thousands of adapters for them to do whatever you need to do also.

http://www.psi-hp.com/

If you can't find a valve or whatever at PSI, check out Trident scuba stuff.

[Anonymous No.558314]

>>556946
A fire extinguisher then?

[Anonymous No.558319]

>>558283
Regular CO2 tanks run in the 800 pound range.

[Anonymous No.559113]

>>558311
Aren't scuba tanks usually pure O2? I'm not sure I want to chance a bit of a spark accidentally murdering me, plus it might be a bit of a bother to refill them.
>>558319
How do you refill them? Specialized machine?

[Anonymous No.559114]

>>559113

Never. They are just normal air mix.

[Anonymous No.559271]

You can fill them at alot of stores who sell paintballs. We have our own large cylinder, forget the size that we use to fill some of our players co2 tanks. We get it filled at the weld supply shop. As for our hpa tanks. I fill scuba tanks at our local fire department, those then fill our paintball tanks at the field throughout the day.
To fill a paintball co2 tank off a big tank, you weigh them. I'm not going step by step (that's on you tube) it's pretty straight forward.
Even easier with scuba air. Just connect the tanks and open the valve. Till it is equalized (again it's on YouTube)

[Anonymous No.559305]

>>559113
>Aren't scuba tanks usually pure O2?
no, that would kill you.

[Anonymous No.559337]

>>559114
>Never. They are just normal air mix.
you can get special mixes for deeper diving, but normally it is just air.

also related: there was an airgun company making a hand-pump to pump up their pneumatic airguns with. it would pump up to 2000 psi, but I recall that owners said that it was a LOT of pumping to do that--and this was just pumping up the reservoir on the air rifle, which is tiny.