<html><head></head><body><div dir="auto">I have typically used a disk of brown paper formed into a cup, think muffin liner, that is secured with a wrap of tape. <br><br>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.<br><br>Jon</div><div dir="auto"><br>--<br>Jon Lagerquist<br>--</div><br><br><div class="gmail_quote"><div dir="auto">On December 8, 2025 8:17:49 PM PST, Dale Farmer via Stagecraft <stagecraft@theatrical.net> wrote:</div><blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;">
<pre class="k9mail"><div dir="auto">You are creating the burst disk with taping blue painters tape over the muzzle. I would try creating some kind of ring clamp at the muzzle. Something that allows you to open it, pull over a new disk, then clamp it down ready for the next shot quick and easy.<br> First thing that comes to mind is the wire clamp system like they use on mason jars. replace the glass lid with a ring. But that leaves the metal clamps over the barrel, potentially becoming a projectile. So a ring with hinge on one side, and a latch from an old road case that allows it to be clamped down tight.<br> Then it's a matter of experimenting with burst disk material. Different types of paper, parchment, whatever to achieve the desired effect.<br><br>Dale spitballing some thoughts.<br>Good luck, let us know how it works.<br><br><br>On 12/8/2025 6:07 PM, Joe via Stagecraft wrote:<br></div><blockquote class="gmail_quote" style="margin: 0pt 0pt 1ex 0.8ex; border-left: 1px solid #729fcf; padding-left: 1ex;"><div dir="auto">I am making a cannon, and am using a pair of air-cannons. One will shoot out streamers, and the other is just to add a stronger boom sound. I attached an image of my design below. Note that pyro is not permitted.<br><br>The air-cannons are made with PVC pipe and use a sprinkler diaphragm type of valve. Traditionally there are "back pressure caps" taped to the barrel to increase the pressure that builds up in the barrel until the back-pressure cap bursts. This both increases the distance it will shoot the streamers, and also makes more of a boom sound. Otherwise the sound is more of a whoosh.<br><br>I've seen some air cannon makers use a PVC Union fitting. This is a way to attach two lengths of PVC pipe, and screw them together. It is possible to separate them, and apply the tape or paper in the middle of it. But to me, it is much easier to just tape the output of the barrel.<br><br>The reason I am writing, is that ideally I would be able to do another boom. I can have a much larger air tank in the base of the cannon to resupply air. But a 2nd shot requires re-taping the air-cannon. The existing design has a fogger and strobe inside, and those can be used multiple times. But, we really like the boom that we get from the air- cannons. We've tried sound effects, but it just is not as good as the air cannon boom. The barrel of the exterior cannon sort of acts like a pipe organ pipe, and it just feels more like a real cannon going off.<br><br>Of course, I can create multiple air cannons, but I would like to do 4 or 5 shots of the cannon. I think the main thing that makes the boom, is the very quick release of the air. The diaphragm valve is fast, but not fast enough. Anyone know of a way to do this besides taping the output?<br><br>-Joe Dunfee<hr>For list information see <<a href="http://stagecraft.theprices.net/">http://stagecraft.theprices.net/</a>><br>Stagecraft mailing list<br>Stagecraft@theatrical.net<br><a href="http://theatrical.net/mailman/listinfo/stagecraft_theatrical.net">http://theatrical.net/mailman/listinfo/stagecraft_theatrical.net</a><br></div></blockquote><div dir="auto"><hr>For list information see <<a href="http://stagecraft.theprices.net/">http://stagecraft.theprices.net/</a>><br>Stagecraft mailing list<br>Stagecraft@theatrical.net<br><a href="http://theatrical.net/mailman/listinfo/stagecraft_theatrical.net">http://theatrical.net/mailman/listinfo/stagecraft_theatrical.net</a><br></div></pre></blockquote></div></body></html>