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I am building a pneumatic cannon using a modded sprinkler valve and schedule 40 PVC rated to 175psi. As I will use it to launch paintball grenades at people, and fire sabot rounds full of paintballs, I would really love to run it off of a CO2 tank. If I can regulate the CO2 down to 150, then I would likely fill a big 4" PVC expansion chamber with an inline valve, load, and then fire with the sprinkler valve. I intend to make it pump action with a gravity loading clip once I get the basics working...
What regulator should I use to take the CO2 from the tank (at ~800psi) down to my desired 150psi? I have seen the http://palmer-pursuit.com/cart/rock-the-boat-ca-p-741.html, which looks great, but that's $85, which is more than twice the price of my entire cannon so far.
Anyone know of a cheaper one? Anybody used this one? http://www.amazon.com/AG1-Air-Regulator-Tippmann-paintball/dp/B003BM7B1A/ref=sr_1_4?s=paintball&ie=UTF8&qid=1387526409&sr=1-4&keywords=ag1+regulator
Also saw that UP Simple aquatic CO2 reg, but that thing looks like a flow reg, not a pressure reg.
I really don't care if the reg has bottle threads on it or not, as I can easily use a fill adapter lying around to convert to 1/4" or 1/8" NPT...
I got a palmer pursuit regulator on eBay for about $25. I also got a paintball remote line and some high pressure hose for $15, and a harbor freight pressure regulator for $5.
The palmer regulator regulates it down to about 150 PSI, then I adjust the HF reg for the desired pressure. Flow through the HF regulator is crap, as expected, and had a problem seating the 4" piston valve it was attached to.
I will add that this problem was solved by initiating filling right at the the pilot valve, with 50 feet of 1/4" low pressure air hose between the HF regulator and the pilot as an expansion chamber to make sure there was enough of a burst of air to seal the valve.
Didn't think about looking for a Palmer regulator on eBay... Thanks for the tip. Just ordered this one on Ebay.
http://www.ebay.com/itm/Autococker-WGP- ... 2ecd0167b9
Now to just find a 10-32 thread adapter...
Palmer regs are worth the money. This might be a cheaper option: http://www.lowes.com/pd_166441-61735-J- ... Id=1040295
Ah, thanks Jack. That is exactly what I was looking for. I really don't know how I failed to find that in all of my searching before. Probably because it is not on Amazon. I actually snagged a nice Palmer mini-rock reg on ebay for $29 which I think will do the trick. I'll just need to use a T-junction to put a gauge downstream to check the pressure output.
It's too bad that the Kobalt CO2 reg sounds like it is poorly made according to the reviews. Wonder if they will come out with a better one. It would be hugely useful.
Yep, quality seems to have been a bit hit or miss.
I was reportedly successfully used for a BBMG here.
The other thing to consider is that the Palmer regs are often quite touchy with regard to adjustment. I have found mine to be stable over time and temperature (including when I frosted it up rapid firing the large cannon), but a slight change in the position of the screw might well be 40+ PSI. due to the huge input pressure). For that reason, I would insist upon a safety popoff valve or safety burst disk downstream of the Palmer regulator.
Re: Best (or cheapest and easiest) way to regulate a 20oz CO
Yeah, I didn't want to have to worry about PVC shards in my face, so I have two 200psi popoff safety valves downstream. The PVC is rated at 220psi continuous operating pressure so I figure that should be a good margin of safety.
I might pick up that Kobalt in a few weeks and try it out.
Got to thinking that this thing might be more space efficient to lug around and allow for a longer barrel without being unwieldy if I went with a coaxial design.
What do you guys think? In-line design with a chamber behind the valve, or coaxial design? I am using a blowgun to trigger the modded sprinkler valve. Any suggestions on a good way to make this pump action loading with a vertical gravity fed grenade magazine?
I was thinking about just dremeling out the stops on couplings for 2" PVC but I worry that that will still be too tight to slide well and close the bolt. Also, it will probably leak and hurt my performance...
Coaxials are generally hard to make into repeaters I would definitely recommend a QEV/slide valve setup.
Sorry to be a pneub, but I don't understand why a QEV setup would enable a design with faster grenade reloading. I don't need a lot of power to lob a paint grenade ~200 feet or fire a 50 round paintball sabot. I am more concerned about cannon ergonomics and quick reloading. If I can't get into cover quickly or reload fast, I'll be toast. Also... I already bought the sprinkler valve and modded it.
Looking at some of the other pneumatic designs on here, an over/under barrel/chamber config might be better for making the design more compact (shorter). I am not looking to make a large bore semi-auto... just a large bore pump action. Something like a pump action M79. I thought about making a straight M79 but I am too concerned about the hinge not sealing well enough and catastrophically disassembling in my face.
edit: I found a good-looking potential solution for pump action thanks to CannonCreations: http://www.spudfiles.com/pneumatic-cannon-database/topic25304.html?hilit=pump%20action#p368937
I want a magazine like this https://www.google.com/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&docid=xYQ6pi4ZWjGKCM&tbnid=ySP6_9Tf_ygZKM:&ved=0CAUQjRw&url=http%3A%2F%2Fwww.usmilitariaforum.com%2Fforums%2Findex.php%3F%2Ftopic%2F151024-show-us-your-period-military-toys-models-and-trench-art%2F&ei=zE-8UoeLJIvhoATYhYHYDg&bvm=bv.58187178,d.cGU&psig=AFQjCNGpA-W1yNapNBY0XiBvTrWvtMOKQw&ust=1388159205736051.
A three way valve as a pilot shuts off the main supply and fired from a smaller firing chamber, giving you faster valve opening (therefore more power) and more efficiency since you're not dumping air from the main reservoir while piloting.
Link is a bit messed up, do you mean these?
Yes, the first pic is the type I mean. Sorry about the link, I am not quite good with using the post editor to put links in. I am sure I could easily construct a gravity or spring assisted vertical magazine for grenades, but closing the bolt tight enough to fire at around 150psi is a concern.
Quick question about my current blowgun piloted sprinkler valve design: if I give the blowgun a quick squeeze to fire, will the sprinkler valve automatically reclose as soon as I release the blowgun trigger? I am thinking about having the palmer reg supplying constant ~150 psi input to my 4" diameter chamber and just firing with the modded sprinkler valve using the blowgun. The other possibility is just adding this button valve http://www.amazon.com/gp/product/B0098W ... UTF8&psc=1
between the palmer reg and the 4" air chamber to allow manual control of when it is filled.
Do you think that is necessary or a waste of a valve?
I only have experience with combustion spudguns prior to this.
Not really, a tight fit should do.
That's the theory.
Cool. Thanks, Jack. I am going to go with an in-line design with the main supply coming in the back of the firing chamber, then a modded sprinkler valve between the firing chamber and the bolt.
I'll post some pics of the build process along the way. Just waiting on some PVC fittings to arrive after ordering them online from Homedepot.com. They aren't the fastest...
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