Paintball

[Brewtt]

Originally Posted by Jmayhak

umm two questions

Can you put gun oil on the top of a 12 gram? I do that with the first one of the day and just shoot it all out with no balls. Is that bad?

Can you put oil on the top of a CO2 tank? I do that sometimes too. Just shoot a few shots after dropping some oil on the tank.

This article got me worried...how long should you keep co2 tanks? I've had some that I got from other people that I don't even know how old they are. wait, is this article about nitro stuff only? If the tank has scratches on it...should I get rid of it? where do I get rid of it? Is there an article about this somewhere I can read? haha, I don't want my co2's to hurt my or my friends from lack of knowledge.

You are fine. Don't worry.

CO2 can NOT ignite. CO2 is what is used in many fire extinguishers.

There is already oil in your 12-grams. Shooting oil through your gun with CO2 is perfectly safe.

Your CO2 tanks have the date of manufacture stamped on them. They are read in the form of "06^04" Meaning "made in June(month six) of 2004."

CO2 tanks are cheap so it's good to buy new ones or exchange them for 'in-hydro' full ones at Wall-mart when they get old.

[Big Nasty]

Something else this has caused me to think about is the purchasing of used HPA systems. Apparently some of the flash fires being cause are contained on the inside of the tanks, and it may be difficult to identify these tanks as a simple cleaning could be done to the outside and then sold to unsuspecting buyers.
I would be wary buying a used HPA system form someone you do not trust or from places like PBnation or ebay.

BTW thanks for the sticky....shows you care and its greatly appreciated.

[Assnolax]

Bauer told me its fine to use dow 55 on the compressor side for orings so I bet its probably okay to use on the fill nipple side too.
Worth checking into at least

Ive never used grease myself on my fill nipples. When they start leaking the oring is chewed up anyway so dont think greasing will help the leaks, just saying that might be a safe/safer option if someone insists.

[BlindeSeher]

Thanks for posting, very good to know.

Makes me glad I run my gear off good old CO2. Don't even have to go near the compressed air circus.

[Pepper]

I asked a AirGuy about this post that was found on PBN, he replied with this.



“You have just been sent a personal message by Airguy on Oklahoma D-Day.

That link was about 90% BS and about 100% scary hype.
Yes, there is a grain of truth in it - you can cause a combustible fluid (such as oil) inside a tank to ignite under certain circumstances. I've never done it accidentally, but I have done it (once successfully out of roughly 40 attempts) intentionally. It's very difficult to do, and very unlikely that the correct circumstances would occur without someone trying intentionally to make it happen. You've got to understand some thermochemistry and physics (and a little engineering) to figure out what's going on. Some of the stuff he wrote, such as the tank getting hot and melting the cover, blackening the reg, etc. is a straight up lie. It's just not physically possible. I will proclaim him a liar loudly and publicly if he ever spouts off that garbage around me. I can prove with science that his claims are impossible and I'll be happy to demonstrate it with my equipment.

Here's what is going on - when you compress air, it gets hot. The more you compress it, the hotter it gets. The temperature increase is directly related to the pressure increase AS A RATIO. That last part is the important part. I can take air and increase its pressure by 1000 psi and it's temperature can be 700 degrees or 70 degrees, it all depends on THE RATIO of it's compression - i.e. the starting pressure versus the ending pressure. Air under atmospheric pressure is at one bar (short for barometric, one atmosphere). If I pressurize this to 150 psi (10 bar on a gauge, 11 bar absolute with reference to a vacuum), then the compression ratio is 11:1 - started at 1 bar and ended with 11 bar. The air will be heated by roughly 90 degrees C.
If I take that same amount of air (or any amount for that matter, volume does not matter) at a starting pressure of 1500 psi (100 bar) and compress it by that same additional 150 psi (to 110 bar), it will be heated by about 8 degrees C. Why? Both samples of gas got compressed by 150 psi, so why did one get hotter than the other? Because the RATIO is different - 11:1 for the first case, and 11:10 in the second.
Same thing applies to a paintball tank, but lets look at it backward. If the final pressure is 4500 (300 bar), the ratio will be determined by the starting pressure. If you walk up with 1500 in your tank, the air inside will be compressed 3:1 - from 100 bar to 300 bar. It will be heated by about 25 degrees C. If you walk up with 600 psi in your tank (40 bar), it will be compressed 7.5:1 and will heat up noticeably. If you've got 150 psi in your tank, that air will be compressed 30:1 and will get quite warm. If your tank is empty (1 bar) you'll be compressing that air inside 300:1 and the tank will get outright hot to the touch.
In a diesel engine, there is no fuel in the cylinder when the piston starts to compress it. It will compress the air charge in the cylinder somewhere between 19:1 and 25:1, depending on the design of the engine. At these compression ratios, the air gets very hot, usually on the order of about 450 degrees C. This is hot enough that when the fuel is sprayed into this hot air, it will immediately begin to burn. This works regardless of what the fuel is - as long as the air gets that hot, it will spontaneously start combustion of any thing that will burn in oxygen - diesel oil, gasoline, carpet, lamp shades, underwear, you get the picture. These are called compression-ignition engines, and that's essentially what we're talking about doing here with the paintball tank.
So how do you make a paintball tank explode? You have to make hot air (hot enough to ignite a fuel) and fuel occupy the same space at the same time. You obviously can't inject the fuel (oil in this case) after the tank is full - but if you spray some into the nipple just before filling, that oil will be blown into the tank as the tank fills. If the tank is low in pressure to begin with, the RATIO of compression may possibly be high enough to heat the air to the point that it will combust. Yes, it's possible.

Except that it won't happen.

Here's why - the air gets extremely hot under high compression ratios. Let's assume worst case scenario, an empty tank going to 4500 psi, a 300:1 compression ratio for the air inside. This will raise the temperature of that amount of air (one tank volume at one atmosphere, not much air) to an astounding temperature of over 4000 degrees C, or about 7200 degree F. This is WAY above the melting point of the tank - why doesn't the tank burn/melt/blow up? Because that heat is also being diluted as that very hot air is mixing with the incoming COLD air - yes I said cold. The air in the fill station started at 300 bar, remember? As it comes through the nipple, it expands into the lower pressure tank and cools as it does so - in fact when the fill process first starts, that expanding air will be at a temperature about -160 degrees C. This very cold air mixes with the very hot air and resulting temperature is MUCH lower - usually less than 150 C because of the larger quantity of cold air - and this heat is not only too low for combustion, but it's also rapidly absorbed by the metallic walls of the tank. Even a carbon fiber tank has an aluminum shell inside - this conducts the heat out of the air very quickly.

The total quantity of hot air is more important than the temperature here - the amount of heat stored in that relatively small amount of air is very low because it takes very little heat to raise the temperature of a gas (air). The same amount of heat that is given up by one tankful of air under this worst-case scenario from a temperature of around 4000 degrees C will only raise the tank temperature (heating the rest of the air added at the fill station, and the walls of the tank) by about 20 degrees C. Nevertheless, if you could fill a tank FAST enough, the air would heat up faster than the walls of the tank would cool it down, and it might reach ignition temperature. The trick is to NOT fill the tank that fast.

That's why all commercially-sold fill stations use orifice valves of .025 inch or smaller, to slow down the air filling the bottle. I can fill a bottle in less than one second if I wanted to - and if there was any oil in there it most certainly would burn at the high temperatures produced. I don't, because that is obviously dangerous. Any good fill station (I use a couple different designs and I'm about to start selling my own design) use an orifice to slow down the speed at which the tank will fill up. Getting the time down to 3 seconds or longer will allow the air to cool by contact with the tank walls to well below ignition temperature. Check out my stations at DDay - you'll find that fill times are about 6 seconds or longer - double the safe range. I'll be happy to show you the guts of the fill station and explain to your hearts content why it's built the way it is. Even if someone did have oil or other fuel inside their tank, my fill stations will fill their tank slowly enough that the heat buildup is too low to cause ignition.

As I said, I did make happen once, after many attempts. I had to "cheat" also - I never did get anything to ignite using oil. I used a mix of propane and oxygen-enriched air inside a thin polypropylene membrane inserted in the tank and slam-filled it for the one successful ignition I achieved. Even that one did not blow up - it just raised the pressure in the tank by about 400 psi above the fill station pressure, still well within the safety range of the tank. The total quantity of fuel we're talking about here simply does not hold enough energy to dangerously raise the temperature or pressure inside the tank if it did ignite. All DOT approved tanks for sale have at least a 2:1 safety factor, meaning a 4500 psi tank is guaranteed not to blow up below 9000 psi, and it has a 6750 psi burst disk on it to relieve the pressure if it ever does get that high.

Trust me on this one - I've got degrees in both Chemistry and Physics, with 12 years of engineering background. I've been making good money with air and CO2 since I was sophomore in high school and haven't hurt anyone yet. I can and will throw down on somebody with a calculator and a notepad until their eyes glaze over.

Don't be scared - it's just science! :grin:”

Anyhoo I decide he knows what he’s talking about lol
pep

[spawnsharks]

I'm a total newbie to the sport, and these forums. A friend of mine (tallen702) recommended that I check in here for advice, trades and deals on used gear. However, this has been one of the best things I've come across... thanks again for posting and making it sticky... sometimes we newbies get advice that sounds good (like a drop of oil to seal a leak) Thanks for steering me clear of this potential catastrophe.

-Shawn

[Ruckus Fox]

Air under pressure is scary stuff! It ranks up there on the top things I'm afraid of, personally. I still jump when a tank hisses or when someone's O-ring suddenly blows. >< It ruffles my fur all up and gives me one of those 'near death jump-starts.'

*shiver*

But I still play paintball. ^^ It's all good in the end.

Um...as a side note, I believe the rule is

Steel Tanks - 5 year hydro
Aluminum Tanks - 3 year hydro
Fiber Tanks - 3 year hydro

Not sure, but I think there are some aluminum CO2 tanks. One way you can check if it's steel or not is hold a magnet to it. If the magnet clamps, it's steel. If it doesn't, it's aluminum. =)

Correct me if I'm wrong, I think I got that off of some thing that someone was passing around about "rehydroing" and "places near you to rehydro."

And I'm pretty sure that the "2 inches rule" covers all tanks 9oz and below. 3.5ozer's are the same width as 9ozer's I believe, and 7ozer's too. So you should be in the clear.

--Ruckus

[Mr. Furious]

I wish I could find the picture of the guy's trunk lid that looked like it got hit by a missle after his HPA paintball tank exploded in it and basically destroyed the rear of his car.

I've been filling Oxygen and SCBA tanks for years and have had to take classes and tests and recurrent testing to allow me to safely and LEGALLY fill air and oxygen bottles. It amazes me that I can walk into a paintball shop and watch a 17 year old slam fill a 4500psi air bottle and make it almost too hot to touch with no explosion proof sleeve or water tank to contain an explosion in the case of a damaged tank or regulator experiencing a catastrophic failure. People have far too little respect for the potential for life threatening injury that is contained in that little bottle on the bottom of their paintball marker and the people who fill them are far too trusting of the bottle that gets handed to them. A brief but thorough inspection of every bottle and reg assembly should be made before every fill to ensure that the tank and reg are not damaged or coated in oil.

Airguy certainly has science on his side when he makes his arguments but that doesn't change the fact that these "impossible" incidents have occured in the past on several occasions. If they are not possible based on science and physics, how could they have happened? I think his smug attitude and lack of respect for compressed gas will bite him in the rear sooner or later. As soon as you lose respect for something as dangerous as compressed air you are putting yourself and everyone around you in danger. Airguy's science does not take one thing into account: People. When you are handling, using or filling a compressed air tank that is not yours you have NO idea what stresses, damage, improper maintenance or abusive treatment that tank may have experienced during it's life. Even if it's your tank and it's never out of your sight, you should take the time to inspect it regularly for deep scratches, damage to the fibers or regulator and anything else that may have happened unknowingly to the bottle in a hard dive or slide into a bunker. If you find anything, remove the bottle from service immediately and have it inspected by a technician.

Sometimes it's good to just be safe and err on the side of caution when dealing with something as powerful as compressed air. I have great faith in my transmission's park pin and the parking brake on my car but I still put a brick behind the tires before I jack the car up. Am I being a ***** or am I erring on the side of safety?

Respect HPA tanks like you respect any device that has the potential to seriously injure or kill someone because they do have that potential.

[two_four_878]

Exactly my thoughts Mr. Furious.

I see way too many people not respecting their tanks. I don't know how many times I've seen burst disks and macroline blow from being left in the sun. Or people who have completely covered or removed their stickers that tell them the date on their tank (in respect to the stamp on the tank, do you think these people know to look at that?). I don't trust people, and so I try to stay away from other people's gear.

[Pepper]

I dont know anything about scuba tanks Whats the fill to burst on one of those?