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I've always wondered...

Post questions and info about pneumatic (compressed gas) powered cannons here. This includes discussion about valves, pipe types, compressors, alternate gas setups, and anything else relevant.
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I've always wondered...

Unread postAuthor: Pilgrimman » Sun Aug 12, 2007 2:34 am

Why is it that when I fire my pneumatic, I can't see any white "steam" come out the muzzle, but when I watch a video of the came shot, the camera seems to pick up the "steam"? It's been irking me for a while... :lol:
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Unread postAuthor: spud yeti » Sun Aug 12, 2007 2:42 am

pilgramman wrote:irking

Thats one awesome word you got there :D

The camera's at a different angle than you are, or your eyes blink when its fired (natural reaction when noise is created; try clapping your hands in front of your eyes :wink: ) thus missing the steam. Or its boogie-man fart that can only been seen on camera :D
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really good quote/phrase here
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Unread postAuthor: frankrede » Sun Aug 12, 2007 2:47 am

Lol^
You can't see it, the camera doesn't blink so it does, like spud yeti said.
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Last edited by frankrede on Sun Aug 12, 2007 3:16 am, edited 1 time in total.
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Unread postAuthor: spud yeti » Sun Aug 12, 2007 2:50 am

frankrede wrote:You can see it, but the camera doesn't blink like spud yeti said

I didnt say the camera blinks, I said he blinks! It would e cool if cameras could blink though.....
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really good quote/phrase here
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Unread postAuthor: frankrede » Sun Aug 12, 2007 3:15 am

yea sorry the sentence is missing punctuation whoops lol
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Re: I've always wondered...

Unread postAuthor: MrCrowley » Sun Aug 12, 2007 4:38 am

Pilgrimman wrote:Why is it that when I fire my pneumatic, I can't see any white "steam" come out the muzzle, but when I watch a video of the came shot, the camera seems to pick up the "steam"? It's been irking me for a while... :lol:


Do you mean like in this video of mine:
[youtube]http://www.youtube.com/watch?v=5ui987L3T10[/youtube]

I've only ever really noticed it on piston valved guns of decent size, not small solenoid valved pneumatics. Though mabe because I have a larger chamber volume then you I pick it up with my eyes anyway, it lingers for about 10seconds.
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Unread postAuthor: Marco321 » Sun Aug 12, 2007 4:50 am

I have noticed it on my ball valve gun, but not on my sprinkler. There is a relatively simple explanation..

What happens is the air is under pressure in your chamber and heats up a bit (not much at all i just thought i would say). When the air gets released into a low pressure environment, it rapidly cools down, the moister in the air turns into liquid and you see it as the stuff coming out the end of the gun.

They use this in some industrial applications to rapidly cool gases.

EDIT: Now to answer your question... My gun did it with a very large chamber, it was good smoke. But now my sprinkler gun has a much smaller chamber and barrel. It still creates it just a little, but it disappears very quickly. The reason is probably more air under pressure means more air cooling down quickly, meaning more smoke stuff. This could be wrong, but it makes sense in my mind.
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Unread postAuthor: Modderxtrordanare » Sun Aug 12, 2007 11:37 am

You only really see things at ~30 "frames" a second I believe. That's why you don't notice you're lights flickering on and off due to the current alternating back and forth.

Maybe because your camera has a higher frame rate it picks up the gas on film for a brief period. Or maybe it's because you're looking at a different angle than the camera.
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Unread postAuthor: noname » Sun Aug 12, 2007 11:56 am

It works with a hybrid and no barrel, but I just saw a very faint jet of steam blasts out about 8 feet and kick up a hell of a lot of dust.
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Unread postAuthor: Fnord » Sun Aug 12, 2007 12:11 pm

I just tried it too. I can see a faint hint of vapor with no barrel on my hybrid, and a very slight vapor when I vent ~60psi out the schrader valve.
It really depends on how humid the air is at the time.

You only really see things at ~30 "frames" a second I believe. That's why you don't notice you're lights flickering on and off due to the current alternating back and forth.


It is possible to detect higher speeds than 30 fps. I can see a 60hz monitor flicker when I don't look at the center of the screen. The tungsten in lightbulbs doesn't cool down quick enough to produce a flicker.
I can't see normal flourescent lights flickering, though. It's kind of weird.
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Unread postAuthor: Modderxtrordanare » Sun Aug 12, 2007 12:15 pm

_Fnord wrote:
You only really see things at ~30 "frames" a second I believe. That's why you don't notice you're lights flickering on and off due to the current alternating back and forth.


It is possible to detect higher speeds than 30 fps. I can see a 60hz monitor flicker when I don't look at the center of the screen. The tungsten in lightbulbs doesn't cool down quick enough to produce a flicker.
I can't see normal flourescent lights flickering, though. It's kind of weird.


It is indeed a very weird phenomena, most people seem to see at a higher rate when they look out the sides of their eyes. Try staring at your monitor out of the side of your eyes. (My hair gets in the way, but I can see it flickering, I don't remember where I can check what its refresh rate is though)
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Unread postAuthor: Pilgrimman » Sun Aug 12, 2007 2:39 pm

@MrCrowley

Yes, that's exactly it. I never see it when I'm shooting, but it shows up on camera. My gun uses a blowgun-modified 1" solenoid valve.
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Unread postAuthor: frankrede » Sun Aug 12, 2007 3:42 pm

I used to see it with my sprinkler valved cannon easily for a couple seconds , it wasn't large but about 3"
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Unread postAuthor: origin unknown » Sun Aug 12, 2007 5:57 pm

I live in a very humid area, so seeing the blast of water vapor it all very common for me on humid days. Try putting some water down the barrel before you fill your gun with air so some of the water goes leaks past the valve into your chamber. That should make the blast stay longer and larger so you can see it even if you do blink.
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Unread postAuthor: Marco321 » Sun Aug 12, 2007 11:51 pm

All it is, is moisture coming out the end of the gun...

Gas at high pressure going into a low pressure environment cools down rapidly, turning moisture in air into vapor.
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