A Few Questions

[OfTheLion]

Hello,

Well, I have run into a bit of a speed bump in my quest to build an airsoft BBMG. Unfortunately, I cannot continue on to begin building until I resolve this issue. It originally was going to be a M2 Flamethrower, but now my friends are encouraging me to build a Browning 1919 replica. I like the idea, and I am fully capable of building the gun. The only problem I have is the power source. In the beginning stages of my design, the power was going to be 3 PVC pipe compressed-air reservoirs on my back. Then, while I was researching, I found that another BBMG builder, NeoSpud, used a CO2 tank on one of his guns. This got me thinking about using CO2. I have heard that it is more reliable and powerful than compressed air, but I am not sure how to hook it up to my gun. So, my questions are:

1) What parts are necessary to connect a CO2 cylinder to a section of PVC pipe?
2) Is a 20 lb tank too large or too small to meet my needs? (Remember, this is airsoft.)
3) Are there any cons to using CO2 over compressed air?

Thanks in advance,
OfTheLion

[mattyzip77]

The only con to using CO2 is that its rather expensive. You need to give more info for a parts list. You will need a few different size bushings and adapters and so on. Try to draw us up a diagram with chamber size, barrel size, and so on. Good luck!!!

[Gun Freak]

Matty, compressed air is free

CO2 can get expensive. Just the rig will set you back about 150 bucks. First, are you willing to spend that much on just an air source?

[OfTheLion]

Thanks Matty. To clarify, I was talking about compressed air from an air compressor, I apologize, I should have been more specific. If I get time, I will try to get a more detailed diagram up. I've already drawn a simple sketch, but it's not very detailed, so I'll try to get an improved one up. (I've been pretty busy with school lately. =P)

To GunFreak:
Is it worth it? I have some money saved up, but the construction of the gun itself may set me back in how much I'm allowing myself to spend on this...

[Gun Freak]

First, locate a place you can refill. If you're powering a big bbmg with it, I think you'd want to refill quite often. I know it holds a lot of air but it can't be that much. Then, calculate refill costs (~3 bucks a bottle), and all that nonsense, so is it worth it? IMO, no, but for some people, yes. I say, go for compressed air. You'll save a #%$&@ ton of money.

[OfTheLion]

Well, The only downfall to using compressed air for me is that I play almost exclusively in the woods, and almost never at my own house. So, bringing an air compressor is out of the question. With a CO2 tank, at least it would be semi-portable. Also, I have heard that CO2 is stored in a liquid state, so wouldn't 20lbs of liquid be a lot of gas?[/i]

[Gun Freak]

Ok, a 20 pound tank is another story. First, plan to fork out at least 200 unless you find a good deal. I think a 20 lb tank would last you several matches, but carrying it around is not exactly a walk in the park. Unless you plan on this gun being a turret and not mobile?

[mattyzip77]

Matty, compressed air is free

CO2 can get expensive. Just the rig will set you back about 150 bucks. First, are you willing to spend that much on just an air source?

Oops, I meant CO2, you know what I meant meenie, my bad dude!!!

[OfTheLion]

Sorry, I didn't specify what size tank, my bad. In reality, I'm not going to be hauling this thing around, (Its actually going to be a steel (?) shell with a BBMG stuffed inside.), so it can be a slightly heavier tank. (That's going to be housed iside several .30 cal ammo cans stacked, welded together, with a cavity in the middle for the tank.) I might have to look into a smaller, maybe 10 lb. tank, but I actually found a cheap 40 lb. tank on craigslist. (No way I'm using that...)

[jor2daje]

another you may want to look out for when using co2 is it cools when it expands so if you are using alot in a pvc chamber without the proper regulator/stabilizer you may freeze a pvc a gun making it very brittle.

[OfTheLion]

I have heard that. Thanks for the input, jor2daje. So is that what a regulator is for, to make sure the CO2 doesn't get too cold as it expands?

[jor2daje]

regulator controls the air pressure, liquid c02 at roomtemp is about 900psi i believe, a regulator would keep that down to a safer level from 50 -500ish psi

[saefroch]

Regulators ensure only that the pressure on one side is not allowed to rise too high through the regulator. They shut off flow when pressure on one side reaches a preset pressure.

CO₂ has one drawback against air, the SOS, but you're probably not concerned with that for this application.

So far as the cooling is concerned, you'd have a similar problem with very high-pressure air, but to a slightly lesser degree unless you're carrying it as a liquid. To avoid the issue of temperature drop on the PVC areas, people usually suggest an expansion chamber, which will allow the gases to pick up heat from something other than the PVC, some metal piping or ideally the air outside.

[OfTheLion]

Oh, that makes sense. Thanks, I didn't previously know what it did, I just knew I needed one. Due to school starting, I haven't really been able to get that involved in this project. Just recently my friend brought up the subject of an airsoft 1919, and I thought, hey, I bet I could do that! Now, I'm trying to find the dimensions of the real 1919, so I can start getting this thing drawn up.

Also, what kind of tubing could I use to feed the CO2 to the gun itself? Does air compressor hose work?

[Gun Freak]

Compressor hose will work if it is rated to the reg's output pressure.