<html><head></head><body><div class="ydpc62e5b20yahoo-style-wrap" style="font-family:Helvetica Neue, Helvetica, Arial, sans-serif;font-size:16px;"><div><div dir="ltr" data-setdir="false">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.</div><div dir="ltr" data-setdir="false"><br></div><div dir="ltr" data-setdir="false">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.</div><div><br></div><div dir="ltr" data-setdir="false">I guess a completely different approach is to upgrade the audio system wattage on that side of the stage.</div><div dir="ltr" data-setdir="false"><br></div><div class="ydpc62e5b20signature"><div style="font-family:Helvetica, Arial, sans-serif;font-size:16px;"><div dir="ltr" style="font-family:Helvetica, Arial, sans-serif;font-size:16px;">-Joe Dunfee<br></div><div dir="ltr" style="font-family:Helvetica, Arial, sans-serif;font-size:16px;"> 717-203-8670 Cell<br></div></div></div></div>
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On Tuesday, December 9, 2025 at 01:51:20 PM EST, Jerry Durand via Stagecraft <stagecraft@theatrical.net> wrote:
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<font face="Arial">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. <br clear="none">
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For the lowest of dead simple, a wheel for a handle on the valve,
wrap with rope... yank.<br clear="none">
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<div class="ydpc62e5b20yiv0395202661moz-cite-prefix">On 09-Dec-25 21:40, Joe via Stagecraft
wrote:<br clear="none">
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<div dir="ltr">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.</div>
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<div dir="ltr">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.</div>
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<div dir="ltr">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.</div>
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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).</div>
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<div dir="ltr">Jon, can you provide a link
to the type of valve you were talking about?</div>
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<div dir="ltr" style="font-family:Helvetica, Arial, sans-serif;font-size:16px;">-Joe</div>
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<div> On Monday, December 8, 2025 at 11:39:25 PM EST, Jon
Lagerquist via Stagecraft
<a shape="rect" href="mailto:stagecraft@theatrical.net" class="ydpc62e5b20yiv0395202661moz-txt-link-rfc2396E" rel="nofollow" target="_blank"><stagecraft@theatrical.net></a> wrote:<br clear="none">
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.</div>
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