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CO2 meter consept

Post questions and info about pneumatic (compressed gas) powered cannons here. This includes discussion about valves, pipe types, compressors, alternate gas setups, and anything else relevant.
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Unread postAuthor: Orpackrat » Thu Mar 29, 2007 9:12 pm

pimpmann22 wrote:Wow, I can't remember how many of times I've brung this point about in CO2 discussions. A major problem with exposing ball valves to a 'freezing liquid' is that it can possibly freeze your valves up. I don't think I have to go out on a stint as to why thats bad.

Just spend some money, and buy the damn real thing! No sense in chancing your safety on something you whipped up for 5$ with Gorilla glue, duct tape, and paper towels.

*wishes that all discussions of homemade CO2 regulators stopped*


I have built 3 cannons that are powered by Co2, the first was powered by a 12 gram, the second and third by a 9oz Co2 tank. Regular steel pipe and brass ball valves can handle the pressure just fine and the freezing temperatures of the liquid Co2 does not freeze the valves. Half the time I fill my expansion chamber with liquid Co2 for a bigger bang. I use about an ounce of Co2 per shot, sometimes more.

You can get high flow Co2 regulators about 125PSI for about $70-120 depending on if is is adjustabe or a fully adjustable regulator for a Tippmann 98 Custom for around $35.
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Unread postAuthor: Orpackrat » Thu Mar 29, 2007 9:17 pm

Scope wrote:12g are still 800 psi... so unless your calculate everything out and have the right temperatures and altitude you ahve a chance of pverpressuring.
you could do all the calulations and find out how much space it would take 12g of co2 to expand to say 100 psi.... but then temperature would have a good amount to do with it because when co2 expands it gets cold. Which will make w.e you are using brittle. Also when co2 is cold it doesnt fully expand but leave it out in the sun and it will jump in psi. I kno that a 20oz coz tank can go from 700 psi up to 900 psi, and at room temp are about 800psi


I would say that Co2 can get a bit higher in pressure if left out in the sun. I had of few of my 9oz Co2 tanks burst their 3,000 PSI burst disks a few weeks ago.
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Unread postAuthor: SPG » Fri Mar 30, 2007 5:08 am

You're just going to use 12gram cartridges? Then buy a CO2 tyre (tire) inflator from a bicycle shop.

Image

This is the Ultraflate, which I can recommend highly, it's good because it accepts unthreaded 12grams (cheaper) and also threaded 16, 25 & 45 grams.

Check here to see loads more. http://www.genuineinnovations.com

Most of them have already got some form of regulator/safety in them to stop you popping your tyres (tires) much past 100psi.

BUT they've got teeny tiny valve ports to you're not going to fill your chamber so quickly that you can't check the pressure as you go along. After all cyclists don't want their tubes exploding in their faces any more than you want your chamber exploding (believe me kevlar belted tyres (tires) exploding can make a mess like PVC)

Go on they're only about $20-30 cheaper than a paintball set up.
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Unread postAuthor: AmYisroelChai » Fri Mar 30, 2007 10:03 am

Just to follow the discussion...

Bluetooth are you trying to create a semi-auto cannon that auto refills to a reset PSI after you fire?

If so great I am too. But the guys (and girls) are right - for that type of PSI go for a Regulator.

Forget CO2 though its old school and volatile because of the cold issues. Compressed air is safer and can be filled for free at most Paintball fields.
20oz Tank -$40 (if you look around)
Regulator ~ $75 ( I am guestimating here) -You want one that comes down to 100-120PSI for Spud Gunning. Maybe 40-70 PSI for Paintball mortars.

Either way.
For $175 including all parts you can put together self filling, semi automatic cannon. And with a little ingenuity maybe make it bolt style so you can load the barrel by sliding up the sleeve.

Besides the price (which is unavoidable because of the hardware) is that where you were going? If not I will post a separate discussion once i am under way with mine
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Unread postAuthor: SPG » Fri Mar 30, 2007 11:13 am

While caution is a good thing, aren't you guys being a little over cautious? He's talking about using 12gram cartridges only.

Take a look at this Inflation and Yield Chart HERE. It states that ONE 12gram cartridge will fill a 26" MTB tyre to 30psi/2.1bar.

Now the volume of a 26" MTB tyre is about

    (pi x radius of tube squared) x (circumference of tyre)

    or

    (3.141592645 x 1²) x (2 x 3.141592654 x 13 )
256cubic inches.

And that's at 30psi.

So for a pneumatic at say 120 psi, using the simplest equations of

    p1 v1 = p2 v2

    30psi x 256 ci = 120psi x 64ci

as long as your chamber has a volume of about 64 cubic inches you should be fine.

And all that for about $20
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Unread postAuthor: Brian the brain » Fri Mar 30, 2007 4:59 pm

Regular steel pipes and fittings can take 800 + psi???

Can 2" steel fittings???

I'd love to know for sure...
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Gun Freak wrote:
Oh my friggin god stop being so awesome, that thing is pure kick ass. Most innovative and creative pneumatic that the files have ever come by!

Can't ask for a better compliment!!
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Unread postAuthor: schmanman » Fri Mar 30, 2007 5:07 pm

SPG wrote:You're just going to use 12gram cartridges? Then buy a CO2 tyre (tire) inflator from a bicycle shop.

Image

This is the Ultraflate, which I can recommend highly, it's good because it accepts unthreaded 12grams (cheaper) and also threaded 16, 25 & 45 grams.

Check here to see loads more. http://www.genuineinnovations.com

Most of them have already got some form of regulator/safety in them to stop you popping your tyres (tires) much past 100psi.

BUT they've got teeny tiny valve ports to you're not going to fill your chamber so quickly that you can't check the pressure as you go along. After all cyclists don't want their tubes exploding in their faces any more than you want your chamber exploding (believe me kevlar belted tyres (tires) exploding can make a mess like PVC)

Go on they're only about $20-30 cheaper than a paintball set up.


yeah, what he said!


here's a thread I posted a long time ago.

http://www.spudfiles.com/forums/viewtop ... c&start=0&
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Unread postAuthor: Orpackrat » Fri Mar 30, 2007 8:56 pm

Brian the brain wrote:Regular steel pipes and fittings can take 800 + psi???

Can 2" steel fittings???

I'd love to know for sure...


I have not used 2" yet, the largest I have used is 1" steel pipe and smaller and they handle the pressure just fine. You just need a bit of teflon tape and make sure there are no leaks. The extreme cold dosent bother ball valves either.
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