[SML] Cannon burst from air cannon

[Richard Niederberg]

The valves in the lake at the Bellagio in Las Vegas reset very fast, but
are pricey.

/s/ Richard
_________


On Tue, Dec 9, 2025 at 11:28 AM Joe via Stagecraft <
stagecraft at theatrical.net> wrote:

> I've used ball valves created for garden hoses on manually operated air
> cannons before. They are indeed fast, though I never got the same boom that
> the pressure cap was able to create.  I looked at the PVC pipe ball valves,
> but they were MUCH too stiff to open with the speed that the garden hose
> version would operate.
>
> When I started to use the electrically operated diaphragm valve (i.e. the
> sprinkler valves) They had a much greater air flow, but I would get what
> sounded like a tuba sounding a note rather than a boom. Actually, that was
> for smaller air cannons than the one I am currently designing. No tuba
> sound yet, but no boom from just the diaphragm valve that has 3/4"
> inlet/outlet.  I need something that will allow the pressure to build up
> after the diaphragm valve, then release at some pressure, and then reset to
> do it again.
>
> I guess a completely different approach is to upgrade the audio system
> wattage on that side of the stage.
>
> -Joe Dunfee
>  717-203-8670 Cell
>
>
> On Tuesday, December 9, 2025 at 01:51:20 PM EST, Jerry Durand via
> Stagecraft <stagecraft at theatrical.net> wrote:
>
>
> On pumpkin cannons I've seen ball valves with a way to turn it fast.
> Could be as simple as a spring with a rope you cut.  If you needed
> electrical control, a pneumatic piston fired by a solenoid.
>
> For the lowest of dead simple, a wheel for a handle on the valve, wrap
> with rope... yank.
>
> On 09-Dec-25 21:40, Joe via Stagecraft wrote:
>
> First, it is good that Jerry Durand reminded folks about the explosion
> risks with PVC pipe.  I reminded the folks working with me about that, so I
> at least reduced the temptation to see how loud they can make it.  I
> accidentally created a safety feature on my system by using a bicycle pump
> that was designed for higher volume and lower pressure. Taking it to 70psi
> was the maximum they had enough weight to pump.
>
> I understand the Cv rating (resistance to air flow).  When I searched for
> blast valves for dust collection systems.  However, all the ones I found
> were ball, or knife-gate valves.  None automatically opened at a certain
> pressure, or reset. They were simply valves to direct the air flow to the
> tool being used.  I am puzzled why they called them blast valves.
>
> Here is a quick sketch of how I might imagine a type of resettable high
> pressure valve might work.  Structurally, it is like the air outlet of your
> clothes dryer, or bathroom exhaust fan. However, I added a magnet to hold
> the flap closed until pressure exceeds its holding power. The spring loaded
> hinge on the flap would then close the flap, so it can be used again.
> [image: Inline image]
>
>
> But, I can't find any type of air valve like this, or that is designed for
> releasing at a fairly high pressure (i.e. 60psi).
>
> Jon, can you provide a link to the type of valve you were talking about?
>
> -Joe
>
>
> On Monday, December 8, 2025 at 11:39:25 PM EST, Jon Lagerquist via
> Stagecraft <stagecraft at theatrical.net> <stagecraft at theatrical.net> wrote:
> For valves I found that "blast valves" designed to clean dust collection
> systems do a great job. I remember them having a CV of about 50.this means
> they are making a big hole very fast so lots of air moves quickly,
> producing a good sound with or without a cap.
>
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