Explosions without fire?

[Conner8809]

Well i have a heck of a problem for you guys here at CB. I am doing the show You Can't Take it with you. There are several explosions that happen right on stage infront of the audience, we are not allowed to have an open flame on stage. i was thinking some sort of dry ice bomb in a sealed film canister? You guys are much more creative than me. So help a guy out!

[LightStud]

Originally Posted by Conner8809

I was thinking some sort of dry ice bomb in a sealed film canister?

Absolutely NOT to the "dry ice bomb!"

Buy an air compressor, locate it as far away from stage as possible (preferably in another room), a long hose and a solenoid-controlled air valve, ala confetti cannons. Use of pneumatics is the only acceptable way to make an explosion other than pure mechanical effects (springs?). Nothing else is consistent or reliable enough. Even with pneumatics, Safety is still critical. Use the lowest possible pressure to achieve the effect desired. You could put an eye out, or worse! Make all "shrapnel" out of foam rubber. I seem to recall all explosions taking place "offstage" beyond the basement door when I did YCTIWY, but we did use pyro for the flash and bang.

[TimMiller]

dry ice bombs are cool, but very dangerous. They are not safe, or reliable. The best way is using the confetti cannon trick. Basically you get an air compressor, or just an air tank, stright off the air tank you connect up a soleniod (using 1" pipe), then from the soleniod to a piece of PVC pipe. The PVC Pipe should be at least 2" and make it at least a foot long. Also for something more heavy duty you can use metal pipe, which i would personally perfer, it will not crack or blow apart. The longer the pipe the deeper the boom. Wire the soleniod up to a push button and fire it. I know about 90 PSI will make a pretty good sized boom. Do not exceed 125 PSI for air operated devices.

[codered11343]

Back when I was in high school we did a production of Peter Pan (the play) and we needed to replicate some cannons going off. I don't remember all the details, but we used a small device (about the same size as a deck of cards...more or less) that were placed on stage with a wire running to a switch off stage. When they were triggered it caused a bright flash, a very loud "banging" noise and a clouds of smoke. But I do not know were you would be able to get them or even what they are called.
I will do a little asking around and see what they are and were you may be able to get them, but I believe that are safe because it was just high school students that were running them.

[Conner8809]

would it be possible to simulate firecrackers using a bunch of small pipes and instead of it going BOOM it goes crack, crack, crack? also where could i find a inexpensive solenoid. while safety is my first concern. we have 700$ as a budget as of now. hehe. this may not go over so well.

[codered11343]

do you mean just hitting steel pipes together from off stage?

[Conner8809]

Originally Posted by codered11343

do you mean just hitting steel pipes together from off stage?

no i meant using a solenoid

[Sayen]

I did this show two years ago on a tight budget. We took a party-grade fog machine, a cheepie from a local party store, pumped smoke into a trashbag. For the effect, we played a loud explosion over a backstage speaker, the door from the basement pushed open a bit, and then squeeze the smoke out of the bag. Quick, fast, and convinced the audience. Bits of flying rubber would have made a fun addition.

[jwl868]

Do not use PVC for compressed air piping. (You will find this warning at all PVC vendors product sheets. See for example, Nibco-Chemtrol.) Oil that is often found in air compressor discharges will weaken the PVC. When PVC pipe fails, it splinters and creates flying shards. (The big tube "gun" part is probably okay because it is open-ended – as long as no one does anything stupid.)

Make sure the rest of the parts (valves, fittings, and hoses) are rated for compressed air and the maximum pressure that the system might be subjected to.

Joe

[cdub260]

Originally Posted by Conner8809

would it be possible to simulate firecrackers using a bunch of small pipes and instead of it going BOOM it goes crack, crack, crack? also where could i find a inexpensive solenoid. while safety is my first concern. we have 700$ as a budget as of now. hehe. this may not go over so well.

We had a firecracker effect in last year's Pageant. We used, American DJ Flash Rope, and stapled 8 of them to an 8 ft. long 1x12 board. We used 4 dimmers to power the effect, via a linked cue sequence, with sections of the board powering up in sequence, starting at the bottom, and working up to the top. This was paired with a firecracker sound effect. While it wasn't perfect, as Flash rope cannot be set to fire in sequence, it did a pretty good job of simulating firecrackers. The most difficult part of this was synching the light and sound cues, and even that wasn't too hard.

A google search for American DJ Flash Rope yielded more potential suppliers than I cared to sift through, but the average price I saw was about $80.00 a piece. I would, however recommend using a cable tacker or some other cable fastening device to install the Flash Rope. You should be able to find something at your local hardware store. If you don't have the dimmers available, look into renting some variation of a backpack dimmer from your local supplier.

Oh, and before I forget, Flash Rope is a strobe effect, so you will need the appropriate signage posted at your venue.

Hope this helps.