need a few extra psi now and then?
Sometimes, after I refill my pcp from a low fill tank, I take my Prod and stick it in the freezer for about 20-30 minutes. I could do the same with a pcp that uses a tank, such as an AF Talon.
I only do this when my fill tank gets down to about 2300 to 2500 psi, and I can’t get my pcp up to a preferred 3K psi.
Cold air is extremely dense. Hot air is much thinner. If you fill a pressure vessel with cold air, the psi will rise as that air warms to room temperature.
After 20-30 minutes in the freezer at “0” degrees, the Prod air pressure drops three to four hundred psi. When taken out of the freezer and immediately re-filled from a room temperature tank with 2500 psi in it, the psi in the gun’s air cylinder will rise 200 to 300 psi as the cold airs warms and expands. A max 2500 psi fill can jump up to 2800 psi, or higher.
I’ve found several refills can be obtained in this manner, when the scuba shop is closed.
Please understand this technique can be dangerous! If you fill a cylinder, or bottle, to 3000 psi, then chill it, the psi will drop 200 to 400 psi, perhaps more. If you then refill it from a 3000 psi fill tank at room temperature, the resultant gun cylinder pressure will climb to 3200 to 3500 psi, perhaps more, and possibly damage your gun, or injure/kill you!
Accordingly, this information is posted for educational purposes. I advise you NOT to do this! Just be aware that your gun’s air psi can be dramatically raised with temperature changes. Never overfill your pcp.
Regards,
H 😯 😯 T
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Snort….snort….I love screwing with you guys!!!
You are both right. Freezing a gun is stupid. Cryo-treatment is now cheap but can’t be proven to do a thing, except keep a hot barrel from warping too badly.
Don’t do as I do, just stand back and think….”WTF???”
Demented, but not dead….yet…
Kindly ‘Ol Uncle H 😯 😯 T
ok, cool.
Well we still broke cams and it did not seem to matter if they treated or not.
Perhaps this is true. What can’t be questioned is the fact that they were much more accurate after treatment!
Regards,
H 😯 😯 T
When I was racing lawn Mowers, we had are billet cams set out to be Cryogenic treated, Because we broke cams all the time.
Well we still broke cams and it did not seem to matter if they treated or not.
At least i would think so. Freezing a gun……………HMMMMM?!
Dry air is dry air. You can’t create moisture where it doesn’t exist. I’m assuming that pcp air is scuba grade, and that the dive shop has desiccant filters in place, and working. That’s why scuba divers mouths and throats get dry and sore after a day of diving. That air is so dry, it sucks moisture out of the diver like a sponge.
Mind you, I’m not saying “Try this…”!
I’m saying gas pressure can be manipulated with temperature. It is known as Gay-Lussac’s Law, which along with Boyle’s Law, explains how gas pressures change, and under what conditions. The whole of this phenomena is known as the Ideal Gas Law.
Regards,
Kindly ‘Ol Uncle H 😯 😯 T
Gotta be getting moisture in your gun somewere going from extreme cold to sorta warm.
At least i would think so. Freezing a gun……………HMMMMM?!
neat trick. i like!
Steve, that’s an interesting comment, and worthy of consideration.
I offer this in response. I would place the element of heat and cold into our natural surroundings. I’m certain there are pcp shooters in Alaska, Canada, Russia, and other places where the ambient Winter temperatures reach well below “0” F. I suspect their firearms and pcp’s are consequently exposed to very low temperatures on a repeated bases.
Further impact of low temperatures, and the steels used in gun barrels, is the technique wherein the barrels are frozen to three hundred degrees below “0” F. (Deep Cryogenic Process)This being used as a means to rearrange the molecules in the steel, and increase accuracy by reducing temperature related fluctuation of the barrel, when shooting. It was, and still is, popular with target shooters who would experience very hot barrels with repeating firing. ( http://www.nitrofreeze.com/guns.html )
This technique is still being used, and is a lot less expensive than it was when it first came out.
I believe all pressure vessels made of steel meet strict and extreme temperature fluctuation standards. Even scuba tanks can reach 130 degrees F, or more, when exposed to a hot Tropical sun. That same scuba tank can be exposed to well below zero degree F temperatures in Artic ice diving ventures. Even the aluminum tanks withstand this extreme temperature spread without problems.
As regards heat, having spent 25 years in Texas, I can assure you that any gun I owned was exposed repeatedly to ambient temperatures well above 115 degrees. The metal in those guns sometimes got hot enough to burn your fingers if touched with bare hands.
Aluminum has a melting temperature of 1740 to 1800 degrees F, depending on the alloy used. Most steels, and steel alloys, have a melting point of 2500 degrees F. Thus 50 to 100 degrees above or below an ambient temperature of 85 degrees F, is unlikely to have much of an effect on these metals.
Having said this, I’ve never heard, nor read, of any adverse consequences from temperature extremes on shooting equipment.
However, I am always open to superior knowledge in this matter.
H 😯 😯 T
That does sound dangerous. Steels that are subjected to low temperaturers are alloyed with nickel and/or chromium. Some metals used for extreme low temps aren’t even steels; they don’t contain iron. I’m not sure I would freeze, especially repeatedly freeze, a steel that wasn’t meant for such an environment. What does anybody else know about this?
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Would it make sense to pump cold air into the tank and not freeze the entire tank? If cold air is denser you would get more air into the tank with each pump. The pressurized air would quickly warm once in the tank so it would not work as effectively as freezing the entire tank. However, it would be significantly less likely to damage O rings or seals. Just not sure if it would be worth the effort.