flash pots...only not

egorleski

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Apr 27, 2006
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So were doing les mis in a theatre where we cant us flashpots. that makes the baricade considerably more difficult. I was thinking of using somthing small like film canisters filled with something like sawdust and then compressed air/co2 to get the look like bullets are hitting the baricade. Anyone every try somthing like this? any ideas for a good material to blow out? i feel like saw dust may just make the stage more slipery then we want. I have been toying witht he idea of some metal shavings so it will catch the light or maybe using a slightly more corse wood shavings...

Thanks
 

koncept

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what about compressed air and glitter in fim cases... that would sparkle and catch the light, toss in some saw dust with it. that might provide you with the "fire" part of the bullet and the "hit" or one...
 

sound_nerd

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Toronto Ontario
I'm very interested in this as well....I'll be keeping an eye on this thread! I need something along these lines in a larger format. My original idea was large PVC canisters piped with compressed air mixed with a compressed fog. The trigger system I've been working on is dmx based with electronic air solenoid valves.
 

Footer

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I did a very simular thing about 6 years ago for a show. We needed halfway realistic pyro without doing live fire. What I did was cut 5/8 PVC tubing to 1' pieces then put a 1/2 barb on the end. We had a raked floor that we could drop these tubes in. They were plumbed with 1/2 hose up to a patch that we could patch them into 6 cylonoid valves (we had over 30 lines). The valves where fed at 140 psi via a nitrogen tank. The tubes where filled with a mixture of shredded mylar and talc powder. This system was rather easy to build and to set up (we set it up and loaded it in 30 min at IHSTF).
 

egorleski

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questions for footer: Why did you go with talc powder as opposed to a saw dust or similar? does talc give u better traction or just available cheap? Talc scares me a little in the whole maybe it causes cancer we dont really know aspect. Hopefully the exposure would be minimal and it probably wouldn't matter but i doubt its really even worth the thought.

second why nitrogen? just couldn't get the pressure u needed out of an air compressor?

While were on this whole concept... anyone ever use this same technology to make guns that fire safely on stage? i could see installing a c02 cartrige to stage guns and just blowing out a little saw dust like the gun is actualy firing... thoughts?
 

Footer

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Saw dust is not fine enough to give a realestic smoke cloud, also you REALLY dont want to even think about breathing it. What we did was pack the tubes nearly full of mylar then put a dash of baby powerder on top. The reason i went with nitrogen was to get the pressure up. The valves i had where rated at 150psi (and would lock up at 160). The most you can get out of an air compresser is 110 max, and you have to deal with putting the compressor somewhere that it can recharge and NOT be heard. The nitrogen gave a sustainable volume of air over a long period of time and that extra 30 psi gave me about 3' more of a shot. If I was back in my apt. I would have some pics to send to you, but I am not, but will be in 2 weeks. I can post some pics of the setup then. Also, where do you hear that talc causes cancer? Everything these days causes cancer!
 

koncept

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i have used some air compressors that last for awhile and get higher than 110, are you sure that was not a limitation of your regulator/compressor??
 

egorleski

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Everything these days does cause cancer... at least in california. they say talc causes ovarian cancer and causes lung cancer in rats and evidence in humans is not conclusive. I think maybe a fine flour then may be best. if it is fine enough to get a good smoke cloud then you know it is edible and dont really have to worry about that then. I dont think we will be doing that many shots so i think that with a couple air compressors charged prior to the show and just not plugged in so they dont automaticaly recharge we should be able to do it. im also looking into the c02 route. in your system were u able to fire them individualy or was it a machine gun like effect with many shots in quick succession? once i get back to school ill make some mockups and start testing what things work best for what we are doing and post some pictures and such.
 

jwl868

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Pittsburgh, PA
When using compressed gas, be aware of the pressures involved. The compressed air (from a compressor) is usually only around 150 psig. Carbon dioxide will be around 800 psig. I'm not sure about compressed nitrogen, but I am under the impression that a full cylinder is at at least 2,000 psig. When using bottled/cylindered gases, you'll need a regulator, and you should give some consideration about how to prevent someone from changing the regulator setting.

The tubing, valves, and fittings what work in compressed air systems may be dangerous to use in higher pressure systems.


Joe
 

Van

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On the subject of Talc Vs. Flour for the effect, let me say we recently produced " The Mercy Seat" ( don't do it unless you like torturing your audience. I can see it now, The Git'mo players present "The Mercy Seat". People screaming running in terror. Sorry I digress.) The show takes place in the days following 9/11 and the entire set was covered in dust. After a ton of research we found that Rye flour is the best material for a "dust", very few people are allergic to it. Equity doesn't have any issues with it, it's realatively cheap. and it's very powdery. if your going to go with the pnuematic / powder solution I feel Rye flour is the best way to go.
Remember Talc and Asbestos come out of the same mines. There's a reason I used Cornstarch powder on my babies butts.
 

saxman0317

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western NY
Footer4321 said:
Saw dust is not fine enough to give a realestic smoke cloud, also you REALLY dont want to even think about breathing it. What we did was pack the tubes nearly full of mylar then put a dash of baby powerder on top. The reason i went with nitrogen was to get the pressure up. The valves i had where rated at 150psi (and would lock up at 160). The most you can get out of an air compresser is 110 max, and you have to deal with putting the compressor somewhere that it can recharge and NOT be heard. The nitrogen gave a sustainable volume of air over a long period of time and that extra 30 psi gave me about 3' more of a shot. If I was back in my apt. I would have some pics to send to you, but I am not, but will be in 2 weeks. I can post some pics of the setup then. Also, where do you hear that talc causes cancer? Everything these days causes cancer!
no no no...thats only in CA bud... Here in NY everything is k=just flat out wrong anyways
 

Van

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When fine flour is put into the air it is highly flammable. Sort of what happens in grain silos that explode. The fine dust in a big cloud catches fire and spreads rather rapidly.
I wouldn't put any sparks near it then, Of course I think this is point we are attempting to develope a solution that doesn't invovle flame, spark or fire. BTW the PPM for a grain dust explosion are pretty high, but it does only take a spark, even a static electric spark to set off a silo explosion. They aren't pretty, and they are very destructive.
 

draco17315

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York, PA
Trust me...adding metal shavings to compressed air is never a good thing........to dangerous.....you can always use things like styrafoam chunks, saw dust (only if it is far enough away from everyone, flour, stuff like that.....just remember to test ahead of time...load your device, put it in the center of an empty stage or empty room, mark a circle around it that is measured, probably a radius of 12' or so then try several attempts, at least 5 or 6 and get an average "blast zone" so you know your safe distance......if you change what you are loading, remember to re-do your range testing becasue each material will fly differantly...........good luck :)
 

icewolf08

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Trust me...adding metal shavings to compressed air is never a good thing........to dangerous.....you can always use things like styrafoam chunks, saw dust (only if it is far enough away from everyone, flour, stuff like that.....just remember to test ahead of time...load your device, put it in the center of an empty stage or empty room, mark a circle around it that is measured, probably a radius of 12' or so then try several attempts, at least 5 or 6 and get an average "blast zone" so you know your safe distance......if you change what you are loading, remember to re-do your range testing becasue each material will fly differantly...........good luck :)
Necropost warning. Note the lat post was in 2006.

Aside from that you should NEVER use sawdust or flour as they are explosive when dispered and airborne in the correct concentrations. There are plenty of documented cases of mills going up because of this, and I am fairly certain that they proved it on Mythbusters as well. I believe the only approved compund for use like this by the AEA is Rye Flour, wuch still poses an explosion hazard (but less health hazard).

EDIT:
It should also be noted, that almost all of the solutions discussed in this thread are either bad ideas or require a Pyro license (like using squibs for machine gun fire).
 
Last edited:

dramatech

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Mar 12, 2008
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Winter Haven, FL
The enforcement of Pyro use in the theatre has become very stringent as of late. We were using a small flash of flash powder and gun powder in "Camelot". We ran out of electric matches, and didn't have time to get them shipped in. We have one of the largest producers of film pyro such as gunshots in our hometown. We called and asked if they had any we could use, The man who runs the place knew several of us from working on "Sheena", and he told us, that it is no longer a matter of getting a citation, but they arrest you and haul you off to jail for violations. The only legal way to do it, is to have a pyro license, of which there are several levels, have fire marshall approval after a demonstration of the gag, and if you use any open chemicals, some sort of national mixing license. Every state has it's own requirements, and a license from one state is not valid in any other state. Our theme parks in Florida, use prepackaged pyro to avoid the national mixing license, but at that, they still require one level license for loading and a higher license for triggering the gag. Bottom line, If you are a community theatre, a school or less than a large facility with all of the proper permits, licenses and local fire marshall approval, you better leave pyro alone or you might end up in jail. Just because there are websites that sell this stuff does not give you the right to use it. The alternatives that have been discussed are the correct approach, but remeber projectiles from compressed gases or air can kill, so use wisdom,common sense and plan it out with deadman switches, and control of one responsible individual.