<html><head></head><body><div class="ydp6374c1ayahoo-style-wrap" style="font-family:Helvetica Neue, Helvetica, Arial, sans-serif;font-size:16px;"><div><div dir="ltr" data-setdir="false">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.</div><div dir="ltr" data-setdir="false"><br></div><div dir="ltr" data-setdir="false">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.</div><div dir="ltr" data-setdir="false"><br></div><div dir="ltr" data-setdir="false">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.</div><div dir="ltr" data-setdir="false"><br></div><div dir="ltr" data-setdir="false">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.</div><div dir="ltr" data-setdir="false"><br></div><div dir="ltr" data-setdir="false">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? </div><div><br></div><div class="ydp6374c1asignature"><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></div></div></div></body></html>