water vapor
the other morning i was shooting, and i noticed when i shot i saw a small amount of water vapor from the barrel. it was 70 deg. and about 95% humity. i use bsa pump and only fill my gun in the ac in the summer to help with water condesation. now later in the day with the same air it would not shoot out vapor. i think the vapor is not from guns air but from the pressure wave from the muzzle causing condisation in the air around the muzzle. does this sound right and have any of you noticed the same thing?
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Its the surrounding air that’s being cooled and forming condensation, not the source air. SCUBA tanks filled by a shop use dryers that remove almost all the moisture. Just ask anyone who dives, ”cotton mouth” big time.
I can’t speak for the moisture content of edward’s air charge, but I can say that the guns in the video were filled with air from compressors with good air/water separators. The blast of cool air just causes some fast condensation. The day of the shoot that was filmed had humidity up around 95% I’d estimate.
I’ve taken some video at 1000 FPS before and seen some neat effects from the air that is in the barrel ahead of the slug. Pity it all happens so fast.
I assume a scuba tank would not be effected? since its not pulling in outside air?
The Dewpoint of 70° air with an RH of 95% is 69°. Therefore the surrounding air only needs to be cooled a couple of degrees for water vapor(condensation) to form.
The RH has decreased and so has the Dewpoint
95% humidity IS wet air, isnt it? Does that pump have a dry-pac filter?
edward,
Go to this link and scroll down to the movies. http://www.airgunrendezvous.com/rendezvous/read.php?2,3957
Some of them are shot at 420 frames per second and clearly capture the vapor you noticed. Usaually, the vapor disappears so fast that the shooter can’t see it. The movies freeze the action that observers might notice.
The vapor is condensation due to the rapidly expanding air cooling and not being able to hold moisture and also cooling wet ambient air. In case you were wondering, your gun is fine…. unless you filled it with really wet air!
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yes it looks just like that video, and my pump has dry pac and when the temp warms up it does not do it so i think it is condensation from the air blast. also i have never seen evidence of water in the air tank when i changed the valve. thanks i feel better, just don’t want a gun full of water!!!!!!