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Old October 12th, 2005, 05:08 PM   #1
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Affordable & real pyro explosion effect!!

We just had our wood floor resurfaced and there was alot of fine wood dust left over because of the sanding. Well, I was outside burning some rags that had wood stain on them which were mixed in with the dust. I lit the rags and took a shovel to mix them with the dust a little bit. I wanted to see if wood dust would actually burn and it did catch and burn slowly. While moving some of the dust around, I naturally created a little dust cloud. Well, this dust cloud suddenly ignited and it created a flash with little sparkles. It didn't last long, maybe a second, but it was very cooool! So, naturally I had to do it again but with much more dust. So, I got a small pile of dust on the shovel and leaned back to prevent being burned and sort of tossed the dust in the air right over the flames to create an even larger cloud than before. WOW! That was an incredible fireball! The heat displacement from the flash made the small limbs and leaves on the trees above shake. Then I thought that would be a great way to create really affordable pyro effects. I have heard how grain silos have exploded when dust from the grain became too hot from convection or fermentation of the grain and just spontaneously combusted but I didn't know that wood dust was volatile too. I don't know if just the wood dust would ignite by itself or if the polyurethane that was originally on it and mixed with the dust when sanded had anything to do with it being volatile. I think a great application effect for this would obviously be for explosions with miniatures and full size sets but also for a character to throw a small handfull of this in or near a flame that is out of frame to create the flash and sparkles. As always, be very cautious when working with pyrotechnics. Neato!!!

Last edited by James Emory; October 12th, 2005 at 10:17 PM.
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Old October 13th, 2005, 08:11 AM   #2
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Quote:
Originally Posted by James Emory
it was very cooool! So, naturally I had to do it again !
Of course you had to do it again. Like you even had to tell us that. :-)
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Old October 13th, 2005, 08:19 AM   #3
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virtually all dust is explosive. Its a matter of the ratio of combustable to oxygen. Wood, Flour, Iron filings, if the ratio of combustable to oxygen is correct, and a heat source is introduced... BOOM! (Thanks to Mr. Lyle, my long ago physcis teacher... and a pyromaniac at heart)
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Old October 13th, 2005, 08:40 AM   #4
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Quote:
Originally Posted by Richard Alvarez
virtually all dust is explosive. Its a matter of the ratio of combustable to oxygen. Wood, Flour, Iron filings, if the ratio of combustable to oxygen is correct, and a heat source is introduced... BOOM! (Thanks to Mr. Lyle, my long ago physcis teacher... and a pyromaniac at heart)
Ah Richard, you beat me to it. Well stated! If you just think about it, take one particle of a combustible material, it's going to burn up rapidly because of the size. Place several hundred thousand of those particles next to each other in a cloud, and you have a rapid chain reaction as one particle burns and ignites the others near it, etc.

Perhaps this coming 4th of July there will be a new line of 'Emory Fireworks' on the market. ;-)


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Of course you had to do it again. Like you even had to tell us that. :-)
That's classic, thanks for the laugh. Yes, 'boys will be boys' huh?

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Old October 13th, 2005, 08:55 AM   #5
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You guys know what the most commonly used "last words" are?






Hey y'all! Watch this!
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Old October 13th, 2005, 12:49 PM   #6
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Of course you know that I'm going to have to try the other items that Richard mentioned. :O

One great thing about these types of items is that they are safe to handle and transport, not to mention totally legal.
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Old October 13th, 2005, 12:54 PM   #7
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Well, to be fair, that 'ratio' is a tricky thing. Each combustible has a different flash point, and the size of the particle, it's distance from other particles, etc. all play a factor. But yeah, any combustible 'dust' is potentially explosive.
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Old October 13th, 2005, 01:37 PM   #8
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Ohhhhh, they had to resand the entire floor today because they realized the stain was too dark......you know what that means, a fresh pile of wood dust!!!! :O
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Old October 13th, 2005, 11:13 PM   #9
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Quote:
Originally Posted by Richard Alvarez
virtually all dust is explosive. Its a matter of the ratio of combustable to oxygen. Wood, Flour, Iron filings, if the ratio of combustable to oxygen is correct, and a heat source is introduced... BOOM! (Thanks to Mr. Lyle, my long ago physcis teacher... and a pyromaniac at heart)

That's why grain silos explode.

Try pouring powdered non-dairy coffee creamer over a lighter!
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Old October 14th, 2005, 08:05 AM   #10
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We used to ignite the powdered creamer that came in the MRE's when I was in basic-a loooong time ago.

Your tax dollars hard at work :-o

Why is it that if you get a group of guys standing around long enough, someone is going to start setting things on fire?

Actually, I think that's why cavemen worked so hard to learn the secrets of fire. When it's not whooly mammoth season what else are going to do...except light stuff on fire.

Hey, did I just figure out what brought about the end of the ice age????
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Old October 14th, 2005, 08:50 AM   #11
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Quote:
Originally Posted by Reid Bailey
We used to ignite the powdered creamer that came in the MRE's when I was in basic-a loooong time ago.

Your tax dollars hard at work :-o

Why is it that if you get a group of guys standing around long enough, someone is going to start setting things on fire?

Actually, I think that's why cavemen worked so hard to learn the secrets of fire. When it's not whooly mammoth season what else are going to do...except light stuff on fire.

Hey, did I just figure out what brought about the end of the ice age????
Mental image forming of a caveman grunting...Uh oh, shouldn't have lit that....run!!

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Old October 14th, 2005, 01:04 PM   #12
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So what

The trick is not to get things to explode. The real trick is to get the explosion to happen on cue, be the right size and be safe.

My dad was a fireman when I was a kid. I remember him telling me about a woman who was emptying the dust from her vacuum cleaner over an open trash fire (lots of people burned their trash in the back yard back in the 50s). The resulting explosion nocked her on her backside, singed her eyebrows and scared everybody.

Be careful out there.

Rob:-]
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Old October 16th, 2005, 08:29 PM   #13
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About those explosions being on cue...

I use the good old fashion acetylene "bomb" in my films. It is extremely volatile, extremely loud and makes a small intense flame, which can be used as a fuse for things such as sawdust - that and the concussion will push it even farther.

The acetylene bomb can be set off with a bb gun - a silent and ideal trigger for those needing an "on cue" explosion.

Lol... just be careful though - I've had these things go violently wrong as well, but nobody got hurt. We just all lost our hearing for a few days. Ah, to be 17 again.
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Old October 18th, 2005, 10:16 AM   #14
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I hope the ATF doesn't see this thread and get the wrong idea. I only did it the second.......and third time just to make sure it was safe!
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Old October 18th, 2005, 11:31 AM   #15
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Care to explain the acetylene "pyrotecnics" ?
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