If the tanks were pressurized with oxygen then oil inside the tank, even synthetic (synthetics will still combust in high pressure pure oxygen environments) you would have explosion problems. There would be no need for an ignition source. Just the pressure and the flammable oil would spontaneously combust.

But, the HPA tank is a different environment. It is pressurized with air, a mixture of roughly 78% nitrogen with the remaining 22% composed of oxygen and several trace gasses (neon, argon, helium and a small fraction of CO2). The  O2 concentration is not enough to support high pressure spontaneous combustion of standard oils recommended to lubricate paintball markers (Air Tool oil or Hoppes Gun oil).

And the facts are that the regulators built into the neck valves of the HPA tanks need to be lubricated just a bit, which also helps them to self clean. I tried operating two different HPA tanks with no oil. Both tanks developed valve leaks which were "fixed" by adding a few drops of oil through the fill nipple.

Part of the problem necessitating oil through these built in regulators is that trash and dirt gets into the tank when you are doing field refills. Ever gone to the filling station on your field and found your nipple cover has been off while you were playing? Dirt has gotten into that fill nipple. Not much, but enough to eventually cause a problem.

Now if you are meticulous in keeping your fill nipple cover on you may think your tank is not susceptible to dirt contamination. Not true! Your fill nipple may be clean, but the last guy to fill his tank had taken a diving slide into a bunker and he had forgotten to put his cover in place after his last refill. Dirt on and in that fill nipple just contaminated the inside of the quick-connect that you are now connecting to your fill nipple. Grit going into your tank will eventually work out through your tank valve. Even if it causes no problems with the tank regulator, it is traveling through the gas system of your marker with potential to cause leaks in the power valve or wear wherever the gas travels past sliding parts in the marker.

A little bit of oil is essential to help clean and lubricate moving parts through your HPA tank and marker. I also read an article in one of the paintball magazines stating a danger in oil use in HPA tanks. I am not saying that a problem could not exist, the the chance of such a problem is infinitesimally small.

I have been a welder and welding instructor for 30 years. I teach high pressure gas safety. And though I see problems with the lack of training for paintball players filling their own HPA tanks at the filling station, oil explosions are not a significant concern.

it won't explode. theirs no sparks and oil isn't flammable

tecumseh wrote: it won't explode. theirs no sparks and oil isn't flammable

All lubricating oils are flammable, synthetic or mineral, under the right conditions. When conditions are right no "spark" is required for ignition. It is called spontaneous combustion.

Not the asa

Just make sure no oil gets around the fill nipple, thats where it could enter the tank and you could have serious problems when you get you tank filled..

Baratak wrote: First off, careful with the term 'explode'. Very little truly "explodes" it just burns rapidy. As for flameless ignition. Though it's true you can can ignite oil with no flame, such as a diesel engine. It still takes heat. Even with pure O2 you still need fuel and something to heat it up. In compression there is some heat formed, hence again how a diesel works, but if you are firing a gun, you are decompressing... that is why your gun cools slightly even with HPA. CO2 is due to heat of vaporisation, not heat of compression, there is a state change involved. spontaneous combustion still requires heat. It's just the heat is caused by something other then a flame source. A pile of dirty rags, the chemicals from one rag, react with the other to generate heat. A pile of hay, the bacteria inside the hay decomposing it can generate enough heat to ignite the hay. Fire works the same, you have a fuel gas, oxygen, and a heat source. The heat source can be chemical, but it still needs to be there. If you are thinking about items like TNT/C4 that isn't actually flame related. C4 explosions are caused by rapid decompisition, VERY rapid, the resulting gasses are pushed out at near 5 miles per second! C4 is actually fairly stable, without sending electricity through it you can light it with a match and burn it like wood. Lastly not all lube oils are flammable, though basically everything is combustable in the right conditions... Just because you CAN burn something doesn't make it flammable, flammable is defined as "capable of being easily ignited and of burning quickly", Many oils are quite hard to burn, and created for use in environments that you don't want anything flammable in. Sorry got a bit long winded.

Hmmm, let me see where to start. Spontaneous combustion of a sawdust pile take place from heat generated by decomposition. Spontaneous combustion of oil in high pressure pure oxygen requires no ignition source and NO heat...IT JUST REACTS. I have seen the results several times.

Explosion:Many things explode due to their rapid combustion. A tank, or a 55 gallon drum, inside which oil ignites explodes. Dynamite, C-4 and gasses like high pressure acetylene, and other true explosives, detonate

And lastly, nearly all lubricating oils are flammable in a pure high pressure oxygen atmosphere. Some with, but most without, an ignition source. There are few exceptions. Teflon is one that remains inert in a hp oxygen atmosphere, some silicone lubricants and other synthetics created to lubricate specifically in high temp areas (inside jet engines).

The likelihood of any oil igniting and causing a HPA tank to explode is remote.