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CO2 Stokes Mortar

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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Re: CO2 Stokes Mortar

Unread postAuthor: Cthulhu » Sun May 21, 2017 10:15 pm

I simply folded some tin foil a couple times then cut it into a disk about the diameter of the bottle cap (which I had cut a hole into) then I placed the burst disk inside and tightened the cap on to form it. I will try again with a larger dismayed though.

I tested the mortar today, couldn't get it to fire the 12g due to the lack of weight on the projectile and drag from the material it was made of (foam). I guess I'll shove some books in the nose of the shell and lather some baby oil on it.

I'm starting to see why a home made shell would be nice, I'll be looking for valves within the upcoming days.
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Re: CO2 Stokes Mortar

Unread postAuthor: jackssmirkingrevenge » Mon May 22, 2017 6:11 am

You'll be wanting a rubber ring of some description in order to ensure a good seal, something like this:

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Re: CO2 Stokes Mortar

Unread postAuthor: Cthulhu » Tue May 23, 2017 4:32 pm

I've realized the reason I may not be getting the CO2 to puncture is that the fit of the projectile in the barrel may be enough to cause resistance as the air beneath it searches for a way out. Sounds like plenty of projectile modification for me.
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Re: CO2 Stokes Mortar

Unread postAuthor: jackssmirkingrevenge » Wed May 24, 2017 5:47 am

A lightweight projectile that is a tight fit will certainly have difficulty generating enough momentum to puncture the disk. Consider a solenoid "hammer" at the base of the barrel to do the job, perhaps with a detector that actuates it the moment the projectile is in place.
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Re: CO2 Stokes Mortar

Unread postAuthor: WizardNoodle » Wed May 24, 2017 6:45 am

Or try Exacto knife blades glued to the bottom of the mortar.
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Re: CO2 Stokes Mortar

Unread postAuthor: Cthulhu » Wed May 24, 2017 7:16 am

Or possibly just add extra weight to the projectile and add a hole for the air to escape through.

But I've already done that, now my problem is is that the cartridge keeps missing the nail at the bottom.
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Re: CO2 Stokes Mortar

Unread postAuthor: hectmarr » Thu May 25, 2017 1:03 pm

You can create an emptiness to give velocity to the projectile in the direction of the perforating element of the rupture disk, I mean inwards. I opened it to see the method to do this, without taking up much space. It is another alternative to those that have influenced you here. Question to try. Very nice project by the way.
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Re: CO2 Stokes Mortar

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