Points of discussion, pneumatic tanks.

[j.hacko]

Hai forum! This is my first post, so ill start from the beginning.

I've been an active spud gunner for a while, but have only received half of the experience, only combustion cannons. I think its time for me to see if pneumatics are as good ( or better ) than combustions. I have an impression that combustion was like a nitro rc car but then pneumatic would be like an electric less cleaning , maintainance. In this feild I am very much a noob so i would like to get my head around a few things before I start.

First of all, I cant find a suitiable HPA or CO2 tank were I live, ( thats in my price range ) so I think i might be better off making a low pressure ( 180 or so psi ) tank from pvc or aluminium. Something I don't understand is the size of some tanks I have seen on the pneumatic cannons. If i make a large tank will I get the same power ( single shot wise ) as if I made a smaller sized tank ( no regulators )? if this is so, like what I've seen in this vid,



then would it pay off to have two ( or more ) smaller tanks with each on its own ball valve and each one its own shot?

thanks for your help guys J.hacko

[Gun Freak]

You are not making a 180 psi tank out of pvc. And as far as performance, combustion vs pneumatic, pneumatics win any day.

[clemsonguy1125]

Up to a certain point the power increases the larger tank you have it would be dangerous to go above 120 with a PVC tank, I stay below 80 myself

[Gun Freak]

120 is fine in PVC. Above that, BAM! You dead, foo.

[MrCrowley]

Some people have taken PVC that high (180PSI) but personally I wouldn't go above 120PSI with any diameter PVC (1/2" is rated over a 1000PSI I believe). I just don't like plastic and high pressures and who the hell is gonna use 1/2" PVC at 1000 PSI anyway

By the way:

Pneumatic Cannon Showcase
Built a pneumatic cannon? Then post it here! This section is for completed, finished cannons that you have built. Please include pictures and information.

Pneumatic Cannon Discussion
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.

Try to read the description next time, i'll move this topic for you though.

[SpudBlaster15]

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[j.hacko]

Woah, thanks guys! sorry about the placement of this article . but do you guys know anything about alluminium pressures?

[MrCrowley]

Something I don't understand is the size of some tanks I have seen on the pneumatic cannons. If i make a large tank will I get the same power ( single shot wise ) as if I made a smaller sized tank

Download a program called GGDT. It will be complex for you at first but after awhile you will be able to model your cannons using this program and see for yourself the performance difference between the size of your chamber and barrel. You'll notice quickly that a longer barrel is much better than a larger chamber in most situations. Also you'll notice that with small cannons it is better to go higher in pressure and longer in barrel length than it is to have a bigger chamber.

GGDT can be found by searching the forum, the Spudwiki or just in Google. David Hall (member D_Hall), is the guy who made the program and you can find it on his website with a quick Google search.

As for a tank, do you have means of getting to 180PSI in the first place? If you have a large chamber you'll need more than a bike pump. Give us some dimensions of a cannon you have in mind and we can help you out more.

[Hubb]

In general, smaller chambers are reserved for higher pressures as larger chambers are reserved for lower pressures. This means that you would probably be happier with a low pressure / high volume chamber.

[Mr.Sandman]

That's the problem with pvc, or any piping for that matter. As the size of piping goes up, the less pressure it can take. Pvc air chambers usually don't hold a lot of air mainly because it's hard to get large fittings. If you cant afford C02 or HPA then perhaps you could go to walmart and pick up One of these.

[Technician1002]

If you can work with other materials, steel propane tanks are good for a working pressure of about 250

[j.hacko]

Thanks Im thinking of making a multi shot gun, Two chambers each with a ball valve separating it from the rest of the gun. A chamber would be maybe 40 or so cm long 10 cm diameter. I have found a pipe of aluminum that fits those dimensions. Would that work? for two shots? I have a compressor that says it goes to 18 bar (not sure if i want to go that high). Oh and just for curiosity how high do schrader valves go compared to a quick disconnect? BTW I want to use a modded sprinkler valve if thats of any use

[Crna Legija]

if you get a thread in schrader valves it will handle more than QD
about the alu pipe what a re the dimensions of it, id and od

most sprinkler valve cant handle more than 120psi. if you want more pressure than either buy a QEV or make a piston valve

what happened to the Piston valves explained visually thread?

[j.hacko]

What are QED valves?

[Gun Freak]

Theres a QEV and a QDV, but no QED

A QEV is a quick exhaust valve, typically refering to the ones you buy. But some people call their homemade piston valves QEV's.

A QDV is something else though. I think it's Technitian's design... not sure. Just search it.