Nitrogen

[andyfr1968 772]

WHY would nitrogen be an explosion risk?? It's innert!

 

I'm no expert on gasses but logic would seem to say that a gas that does not support combustion ( nitrogen ) would be safer than one that does ( air ).

 

I'm not trying to be a smart-arse but can anyone explain why nitrogen is not safe??

 

Cheers.

[wuzzy 0]

heres a quote i stole off Terry Doe EDITOR OF AIRGUN WORLD "During the past couple of weeks I've spoken to two people who advocated the use of gases other than air in precharged pneumatics. One of them told me that 'all my mates use........' and he named two gasses which he claimed 'improved' the performance of his gun.

 

I asked both callers which other gasses they'd tried, and one had tried oxygen, the other 'knew someone' who had used acetylene. I kid you not. Both of these morons also claimed that they knew what they were doing with gasses. Both were told in no uncertain terms what their status really was, and I suspect both put down the phone with a very much reduced opinion of me.

 

Now, for at least the tenth time since the BBS has existed, can we nail this one right here, right now?

 

Forget the alleged 'advantages' of one gas over another, forget the 'but this gas is inert' protestations and forget completely any idiotic notions of me, and the airgun industry, wishing to hold back the march of progress. The fact is, experimentation with gases other than air WILL lead to someone getting severely injured and possibly killed.

 

The guns are already out-shooting us by miles and air-power is safe, manageable and perfectly capable of providing all we need. Sticking with divers' quality compressed air ONLY, keeps the safety message clear and un-muddied by life or death lessons in chemistry.

 

Please, stay safe, promote safety and never join the ranks of the dangerously moronic. Above all, never, ever use anything but clean, dry air in a precharged pneumatic airgun.

 

Sorry about the sermon, but I'd rather bore you than leave you open to the influence of potential Darwin award winners.

 

Terry "

[wuzzy 0]

i must admit i would take his word for it he has been involved in the airgun world alot longer than me

[SEAN3513 7]

people will always challenge knowledge and that’s fine as long as they are aware of the risks.

 

Ignorance of laws these days doesn't make you innocent

 

The issue is on the internals and seals, different gases attack different rubber compounds, which in turn affect the pressure, an uncontrolled release of pressure IE a burst from a 3500psi full size oxygen cylinder has the equivalent force of 1/2 a kilo of TNT, gauges and Regs also have different internals dependent on the gas used.

 

PCP's are ONLY designed to be used with compressed air !!!!!!!!!

[andyfr1968 772]

Thanks Terry.

I can see (as I hope anyone with at least half a brain can ) that the two gasses mentioned in your post are, er, a very bad idea!

However, Why is nitrogen bad? It's innert, the same density as air, won't blow up or burn.

Like I said, I'm not being a smart-arse, so can anyone please explain WHY nitrogen's not safe to use?

 

Cheers.

[wuzzy 0]

i think its safe to say that pcp's are only tested with air and therefore are only made to cope with air! so who knows how nitrogen pure! would effect the seals i know i wont be testing with it

[SEAN3513 7]

people will always challenge knowledge and that’s fine as long as they are aware of the risks.

 

Ignorance of laws these days doesn't make you innocent

 

The issue is on the internals and seals, different gases attack different rubber compounds, which in turn affect the pressure, an uncontrolled release of pressure IE a burst from a 3500psi full size oxygen cylinder has the equivalent force of 1/2 a kilo of TNT, gauges and Regs also have different internals dependent on the gas used.

 

PCP's are ONLY designed to be used with compressed air !!!!!!!!!

 

 

Thanks Terry.

I can see (as I hope anyone with at least half a brain can ) that the two gasses mentioned in your post are, er, a very bad idea!

However, Why is nitrogen bad? It's innert, the same density as air, won't blow up or burn.

Like I said, I'm not being a smart-arse, so can anyone please explain WHY nitrogen's not safe to use?

 

Cheers.

 

 

i think its safe to say that pcp's are only tested with air and therefore are only made to cope with air! so who knows how nitrogen pure! would effect the seals i know i wont be testing with it

[andyfr1968 772]

i think its safe to say that pcp's are only tested with air and therefore are only made to cope with air! so who knows how nitrogen pure! would effect the seals i know i wont be testing with it

 

I understand what you're saying, Terry, and I totaly agree that messing around randomly with other gasses is really not a good idea.

 

However, nitrogen's what air's mostly made of, it's the oxygen and moisture in air that perrishes seals etc.

 

The original question ( and mine's ) is why specifically nitrogen's no good for a PCP?

[Malt 379]

It seems that this one is far from conclusive. The article about 'other gases' only covers Oxygen & Acetylene, and you'd have to be brain dead to try either of those gasses IMO.

 

I wouldn't advise anyone to fill their guns up with any gas other than air, but from a purely theoretical stand point, personally I can't see how an inert gas such as nitrogen could be any more dangerous than atmospheric air. Would I personally put it in a PCP? No, probably not, because I don't know for certain what the consequences might be.

 

ALL compressed gas carries a risk to it, and that includes the air that you put in a PCP.

[andyfr1968 772]

Hey, folks! This could be the new '.177 v .22, pointed v domed, spring v PCP' !!

 

Nitrogen v Air! The new age of conflict begins!!

 

Oh bugger......

 

To anyone who REALLY understands this question, please, don't be shy and reply??

 

Cheers?!?!

 

Edit... Spelling... It's late....

Edited November 28, 2009 by andyfr1968

[BellySlater 15]

:alcoholic:

[DIVERD 34]

Nitrogen is an inert gas and as said before makes up 79% of air. Never consider using oxygen or acetylene to fill a pcp, it will explode. It may possibly explode when filling. It will cetainly explode eventually when firing. The explosion happens because oxygen lowers the auto ignition of everything it is in contact with. All it needs to ignite is heat and fuel. The fuel is present in the seals and lubricants in your gun and then the heat is added during compression, eg when you fill your gun or fire it. When you then pressurise the gas, you further lower the auto ignition temperature of the guns components so you will eventually have a hot compressed gas in the presence of fuel, a little diesel engine in fact. Acetylene has an explosive range of some 4 - 96%. You really do not want to mess with that.

 

Nitrogen for these purposes, will void your manufacturers warranty, but in pure terms will actually do no harm when firing or filling. It will also not add any advantage in physical terms, unless you have a vast store of compressed nitrogen and no compressed air. Theoretically it will cause less internal corrosion on the parts and seals that air, but the effect is so minimal that it is not any better than divers, medical or aviation grade compressed air, all of which are clean and dry.

 

Other inert gasses will effect the performance of a PCP. Denser gases will accelerate slower and cause a drop in fps. Lighter thinner ones will cause the mechanism to work faster and will cause the gun to go above their legal limit. I was involved in research into this some time ago, for a different application set up but with basically the same mechanism as many PCP's.

[zak-s410 0]

I think il just stick to divers air until one of the top manufacters say it is ok to use any thing else

 

Atb Zak.

[andyfr1968 772]

DIVERD, I thank you!

 

A proper answer to the original question. What you've said makes perfect sense. I wasn't thinking of filling with nitrogen, it's just the first post made me think...

 

It won't blow up, burn, react with anything in the gun, is the same density as air, so why not??

 

Cheers.

[Phantom 631]

Here's a couple of thoughts.

 

Do 'other compressed gasses' expand at the same rate as air? if they expand slower than air then they would surely reduce the velocity at which the pellet moves? If they expand faster, then an increase in velocity would ensue thus making a sub 12 air gun a possible FAC rated gun?

 

But my initial thoughts are along the same reasons that you used to require a FAC for a Umarex, Crosman, Gamo etc co2 powered pistol. Even though most of these produced sub 2ft/lbs at the muzzle.

 

Co2 powered pistols/rifles expelled their gas from the muzzle and I seem to remember in some Fire Arms Regulations they were deemed as Fire Arms because they expelled gas other than air.

 

When someone brought up the idea that a "Gas Ram / Gas Strut" used another form of gas the legislators decided that they only used the gas in the system to propel the piston forward and did not release the gas and so they were deemed 'Air Guns' and not gas guns. I believe they use Nitrogen (but I am open to be corrected here!).

 

Phantom