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Will this work?

Posted: Sun, 11th Mar 2007, 12:33am

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doppelganger

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Ok so i'm about to start filming a present day war film and i want real explosions. My dad and me are going to try this tomorrow because i got the air compressor today.



Just wanted to know what ya'll thought about it.

Last edited Sun, 11th Mar 2007, 3:04am; edited 2 times in total.

Posted: Sun, 11th Mar 2007, 1:42am

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Bryan M Block

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compressed air is not pyrotechnics...


but it should work- people have done all kinds of things like that
Posted: Sun, 11th Mar 2007, 1:48am

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doppelganger

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alright thanks, i just edited my post so i dont sound stupid smile
Posted: Sun, 11th Mar 2007, 2:07am

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BackOfTheHearse

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The stuff in the funnel needs to be really light-weight (such as clumps of moss).

Also, the air compressor should be turned up high. You will also need some sort of triggering mechanism, if even just a simple valve, to release the air in short bursts.
Posted: Sun, 11th Mar 2007, 2:24am

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Jrad

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They did something like that for Band of Brothers so that actors could stand over an "explosion."
Should work!
Posted: Sun, 11th Mar 2007, 2:53am

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doppelganger

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yeah, i got the idea after watching the band of brothers special features, and yeah we have a valve to release the air, im also going to fill the funnel with loose dirt and bark, and crap like that. thanks
Posted: Sun, 11th Mar 2007, 3:02am

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Hybrid-Halo

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You'd be better off using piping rather than tubing, as it's less likely to burst or rupture resulting in low pressure. Rather than just going out and trying to do this it's a good idea both to guarantee success and safety to get someone with a little experience with this on-board. Compressed air can be very dangerous.

On-Set of Project One we used some air canisters which led directly into funnels filled with a light dust substance (in our case I think we used Concrete). If you're going to use a heavier substance then compensate for it by having the air pressure less spread out.

Also, Visual Effects are generally post effects which merge live-action with computer generated elements. Special Effects is a more encompassing term which covers on-set effects such as air pressure explosions.

-Hybrid.
Posted: Sun, 11th Mar 2007, 3:06am

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doppelganger

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alright well we have some pipe to so will try that to. the tubing we have is reinforced though it specialy designed for air compressers, thanks
Posted: Sun, 11th Mar 2007, 4:17pm

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pdrg

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You will get the effect you're after by releasing a large amount of air in a very short time, so either use large-bore piping, or have an intermediate (very strong) box with large bore piping to the funnel and a simple valve that lets you release all the air in one go (as opposed to slowly). This way you fill the box slowly from the compressor, then vent it all at once.

This is how superguns work (Having worked at a bullet-proof-window factory where we had to shoot chickens at windshields at 500mph)

Be very careful - having said the above, I do not reccommend you try it without a qualified technician as it is, as I said, how superguns are made.
Posted: Sun, 11th Mar 2007, 5:06pm

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cinemafreak

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This is how superguns work (Having worked at a bullet-proof-window factory where we had to shoot chickens at windshields at 500mph)
Were they alive or dead before being hurled at the windshield? Chickens don't fly anyway, why not just shoot the window to make sure it meets standards? What a horrible waste of poultry!
Posted: Sun, 11th Mar 2007, 7:37pm

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Big Man

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That with some fire, light, and blur effects in post-production and it should look really good!
Posted: Sun, 11th Mar 2007, 7:45pm

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doppelganger

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im going to test it sometime this week i'll post the results
Posted: Sun, 11th Mar 2007, 8:02pm

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Aculag

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Hybrid-Halo wrote:

You'd be better off using piping rather than tubing, as it's less likely to burst or rupture resulting in low pressure.
It's a good idea to have piping where the air is closed off. So in this case, after the valve, it would be safe to use plastic tubing, since the air is going to be released once it gets to the funnel.

And this way, if the funnel magically becomes so clogged that the air can't get through, and for some reason the person manning the valve can't close it off, you've only got rubber tubing bursting, instead of copper pipe or PVC.
Posted: Sun, 11th Mar 2007, 8:18pm

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Kid

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I saw a picture of a porsche that was totaled by a chicken so however it got there this testing must be important smile

Last edited Mon, 12th Mar 2007, 4:01am; edited 1 times in total.

Posted: Sun, 11th Mar 2007, 8:59pm

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Aculag

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You're drunk.
Posted: Sun, 11th Mar 2007, 9:06pm

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doppelganger

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I saw a picture of a porsche that was totally by a chicken so however it got there this testing must be important
okay... are you like high or something because that made no since what so ever. or maby he just got real excited and and wanted to say a bunch of stuff but couldnt type them as fast as he wanted to so he skipt a bunch of words. smile

Last edited Mon, 12th Mar 2007, 1:40am; edited 1 times in total.

Posted: Sun, 11th Mar 2007, 9:36pm

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pdrg

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cinemafreak wrote:

This is how superguns work (Having worked at a bullet-proof-window factory where we had to shoot chickens at windshields at 500mph)
Were they alive or dead before being hurled at the windshield? Chickens don't fly anyway, why not just shoot the window to make sure it meets standards? What a horrible waste of poultry!
They're freshly dead - they stop off at a battery farm on the way into work, and some poor/lucky chicken gets to walk around and stretch its wings for a couple of hours before having her neck broken, stuffed in a plastic bag, and fired at 500mph.

It's quite interesting from a cinematic point-of-view though - lots of high-intensity lighting, and they'd shoot 100ft of film in a just over a second. Massive bang, the white wall behind turns pink instantly, and the pulverised flesh sticks to the lights and instantly the place smells of roast chicken. Not a single bone or fragment of feather left intact - not one. The 'forgot to defrost the chicken first' gag is just that - these are serious scientists and engineers, not schoolkids!!

Chickens can fly, by the way. So can ducks, which are a similar size. They work on the assumption that most similar sized birds hit by a fighter jet had better not smash the windscreen. If Porsches could reach 500mph, I'd be damn scared of hitting a bird too, but even at 100-200mph, domestic autoglass would stand a poor chance.

end of the science bit smile
Posted: Mon, 12th Mar 2007, 1:45am

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TimmyD

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1 dollar budget wrote:

I saw a picture of a porsche that was totally by a chicken so however it got there this testing must be important
okay... are you like high or something because that made no since what so ever. or maby he just got real excited and and wanted to say a bunch of stuff but couldnt type them as fast as he wanted to so he skipt a bunch of words. smile
"...that made no sense..."

"...or maybe..."

"...so he skipped..."

Are YOU high?
Posted: Mon, 12th Mar 2007, 1:58am

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doppelganger

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Wow I misspelled three words... yep i must be high. What are you my english teacher, come on this is a forum i'm not going to check every word for errors. You must be very bored to point out three words that are misspelled out of a paragraph.
Posted: Mon, 12th Mar 2007, 1:59am

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TimmyD

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Bored I am, sir.
Posted: Mon, 12th Mar 2007, 4:06am

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Kid

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hehe no I wasnt drunk, just a typo, but check this out...

http://www.collegehumor.com/picture:1599175/context/tag:birdintoporsche
Posted: Mon, 12th Mar 2007, 4:04pm

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pdrg

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Imagine that, but 350 MPH faster!
Posted: Mon, 12th Mar 2007, 4:49pm

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cdolsen

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you'll need a tank to regulate the pressure from and a 'ball valve'. go to a plumbing supply for at least a 1' ball valve to release the pressure in a small (under 1 sec pulse) amount of time.

the funnel can be filled with cork pieces and sieved dirt (to remove pebbles and rocks).

there's also a relatively safe 'pyro' effect. fill the funnel with a white-coffee-creamer with a flame source above the creamer. the creamer is not flameable in its packed state. when the creamer 'clouds' through the flame it will generate a fireball. have your dad check this first and stand back 20+ feet when you test it.

another is to search the forum for stock footage of explosions.
Posted: Mon, 12th Mar 2007, 4:59pm

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iggy88

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You a drinkin' man, Kid..?

Anyhow, has anyone seen what Detonation Films has demonstrated with tubing/piping (whatever), a funnel and coffee-mate, a.k.a powered artificial creamer?

You have a flame source, like a candle - - When someone off- screen blows air through the tubing into the funnel (containing the powdered creamer), the resulting cloud-burst reacts with the flame and produces a nice, quick flash-blast. It's safe enough for actors to interact with, if the blocking is done properly.

Of course, the sound effects are added in post...

A note: Don't attempt anything involving any sort of pyrotechnics unless you're absolutely sure what you're doing..! Even with your Dad!
Posted: Mon, 12th Mar 2007, 8:31pm

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doppelganger

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yeah we do know what were doing... or atleast my dad knows what were doing he works with compressors and stuff all the time.
Posted: Mon, 12th Mar 2007, 8:41pm

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Garrison

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I expect a video posted of this thing in action.
Posted: Mon, 12th Mar 2007, 8:53pm

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doppelganger

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yeah the video should be up this saturday/sunday it will also be a tutorial i'm going to put on youtube and my website.

i want to be clear to everybody this is not for stock footage it would work if you put it in front of a black background. but this is going to be an actual explosion that will happen while shooting.

like the kind they did in "Carnage in the Desert".
Posted: Tue, 13th Mar 2007, 12:25am

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BackOfTheHearse

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Well, this is certainly much safer than the dry ice advice I gave to Twisted Studios wink
Posted: Tue, 13th Mar 2007, 12:35am

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doppelganger

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so dry ice... i'm getting some ideas... no i'm just kidding, my parents wouldnt let me do real explosions unless they were safe. sounds kinda ironic
Posted: Tue, 13th Mar 2007, 12:53am

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JohnCarter

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Use peat moss. Looks like dirt and it is light. Broken pieces of dark cork if you can find it. That is what pyro guys use in movies: a mix of dark cork and peat moss. It's light enough so that it will not hurt anyone and fine enough not to cause eye damage if it hits you in the eye - which it might. Peat moss will powder and at worse, you'll have a crying eye for a little while.

Do not put bark as it can break and the harsh parts can damage your cornea if it gets there. Safety is key. Have fun.
Posted: Tue, 13th Mar 2007, 12:59am

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doppelganger

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thanks for the tip, that will help