# Self-contained air supply?



## Revenant (Mar 17, 2007)

I was wondering if a compact self-contained pneumatic source could be made by feeding liquid CO2 from a small bulk bottle (like a paintball bottle) into an expansion chamber. Would it be possible to get enough pressure that way to drive a cylinder? I know the cold would tend to ice up the chamber but that can be dealt with. I'm just looking for a solution to a pneumatic rig that can be moved around without air lines or a huge air tank.


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## Severin (Aug 5, 2007)

I used to be a paintball regular (still have my gear) and output pressure will not be a problem. In fact, you're going to need a regulator to step it down. My 20oz C02 cylinder is rated for 1800psi and a typical fill is going to put at least 1000psi in that tank.

For reference about how long it will last - I've seen portable c02 tanks for tool use claim 500 shots on a brad nailer using a 9oz tank.

Link here

Two properties about co2- The colder it is outside, the lower the tank pressure will be. At 40 degrees, your talking about half the pressure. The other property is that co2 will deliver constant pressure until the tank is about empty- unlike air.

You can also go with HPA- High pressure air. (I've used this too) The pressures are higher than co2 3000-5000psi, so you get more shots per tank. Temperature is not an issue here, but cost is. These tanks are expensive to buy and fill.

Hope this helps


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## Severin (Aug 5, 2007)

Looks like Lowes has something ready to go. Might be worth it if you don't have a tank, regulator, line etc.

http://www.lowes.com/lowes/lkn?action=productDetail&productId=166441-61735-J-6901-100&detail=&lpage=none


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## Revenant (Mar 17, 2007)

Hmmmm.... that looks promising... I was looking into the idea of using liquid CO2 so I didn't have to mess with high pressure, but was afraid the logistics of building something that wouldn't self-destruct or leak. This little gem might be everything I was thinking of... and 90 bucks isn't too god-awful bad... gotta look up more info on that unit... Thanks Severin!


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## gadget-evilusions (Jan 26, 2007)

I have used the paintball nitrogen tank set up to operate some pneumatic things, not haunting related, but I will tell you it's alot better than working with co2. Either way your stuck working with pressures over 1000psi, but that's not really a big deal because on regulator (designed for the tank, don't use a normal air line regulator), can bring you down from 1000's of psi to 60 no problem.


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## Revenant (Mar 17, 2007)

Thanks for the tip Brian. What's the problem with CO2 and the advantage of N2 over it? Just wondering.

So I can get a small (the size of a paintball gun bottle) porta-rig like the one Severin showed me that runs of N2 instead? And could I get it refilled at say a welder's gas supply place? The nearest dedicated paintball supplier around here is a good bit of driving for me.


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## gadget-evilusions (Jan 26, 2007)

Well, the nitrogen tank I use is still a paintball tank, and i dont think the welder supply could refill it. 

The advantage of it over c02 is not having to deal with the ice getting into your props because the c02 is so cold when it starts expanding. 


Another option, if there is a welding supply place near you is to see what they can do for you in getting setup with a small nitrogen or co2 tank, and the appropriate regulator.


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## Severin (Aug 5, 2007)

Revenant said:


> So I can get a small (the size of a paintball gun bottle) porta-rig like the one Severin showed me that runs of N2 instead? And could I get it refilled at say a welder's gas supply place? The nearest dedicated paintball supplier around here is a good bit of driving for me.


I was just looking at that lowes co2 rig, and I'm pretty sure you could buy a fixed screw-in HPA tank, also known as a nitrogen tank and screw it right in to the lowes rig.

Buying a regulator for a Nitrogen HPA tank is going to cost around $65 and another $70 or so for the tank. Then you're going to need hose and fittings to transition to a pneumatic setup. Buying the lowes rig and and a Nitrogen tank is going to be $89 and $70. The hose and fittings are included.

If you can't find a paintball store to fill your tank, try the local fire department. The Scotts breathing apparatus they use is very similar to the HPA nitrigen bottles used for paintball.


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