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First Compressed gas Cannon (rather technical)

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: SpudBlaster15 » Sat Mar 10, 2007 2:12 am

Insomniac wrote:It can't cope with the rapid pressurization/depressurisation over and over and over again.


They sell pressure rated ABS, which is essentially identical to solid core DWV ABS, though rare and expensive. The material can handle repeated pressurization/depressurization just as well as PVC.

That said, I wouldnt use it in a pneumatic cannon, due to the fact that almost all ABS fittings you will find are DWV, short socket type.
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Unread postAuthor: boilingleadbath » Sat Mar 10, 2007 9:37 am

The pressure of propane is highly temperature dependent - but normally is far south of 300 PSI. (I think the emergency release valves on those tanks generally activate at around that pressure)
http://www.engineeringtoolbox.com/propa ... _1020.html

They do have a point, though - propane is more expensive per shot.
(I'm calculating .2$ per 2 liter chamber at 100 PSI)

That said, it looks like you want a fair degree of velocity consistency... so you want something less manual than a ball valve.

I advise you to download and play around with the GGDT... with the acknowledgment that it doesn't have propane as a gas option.
(though I think joanna posted the data needed to enter it as a custom gas on spudtech)
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Unread postAuthor: schmanman » Sat Mar 10, 2007 10:24 am

MrCrowley wrote:I doubt you could get 250fps with a 20" barrel easily.


well, unless you have the valve and chamber to support it.

If you do, you can achieve high velocities pretty easily.


does anyone know what airsoft thingy he was talking about? :?
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Unread postAuthor: jrrdw » Sat Mar 10, 2007 6:56 pm

Don't take these guys flaming you to hart. Your just new to spudding? Pay more attenchion to Mr Crowley's post, for your sizes. Go to the spud wiki and read up on pneumatic cannons and solvent welding before you start building, the link is up top. We do like pictures around here and video's are even better, of your cannon's, just wanted to point that out. Welcome to spudfiles.
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Unread postAuthor: Bluetooth » Sat Mar 10, 2007 7:05 pm

I don't know what he would use a GBB for in his design (BTW GBB means Gas Blow-Back, a gas powered blowback airsoft gun).
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