Grease and compressed air.

Funny isn’t it how little things show up on your basic Stats that people may know little about and could cause a danger to end users.

In this case the search string was “2000 psi hand pump grease”.
Only what is a “2000 psi hand pump”?
The question refers to a class of air weapon (Pre-charged Pneumatic aka PCP) that has a reservoir or air tank to hold a large amount of compressed air. This air is then released by the trigger in a controlled ‘burst’ to propel the pellet up the tube aka barrel.

airriflepair

As an example, here are my air weapon “babies”. (Not to scale)
The top one is my PCP and you’ll see the air reservoir under the barrel.

So, no flying spring powered pistons or gas rams, no hopelessly inept CO2 cough from a ‘sparklet’ type disposable bottle, and no furious pumping of a handle to recharge the weapon for each shot. Just an on-board source of power for maybe 200 shots. Lovely.

Except there is a problem. How to get that high pressure air into the weapon.
What pressures are we talking about? Around 100 to 140 Bar (1450 to 2000 PSI)
There are two ways.
One is fine for now ( i.e. not a disaster scenario) and involves using a diver’s tank which you take to a dive shop and they refill for you with clean, dry, filtered air. This is ‘decanted’ by a thin high pressure hose into your air weapon. Only when TSHTF and electricity and shops aren’t any more, high pressure refilling systems may become a thing of the past on the high street.

The other way is to own a high pressure hand pump.
It looks basically like this.
stirrup pump

It’s a multiple chamber pump that is capable of building up the necessary pressures.
Also a great way to carry out some aerobic exercise!
The penalty is internally it is complex with loads of little ‘O’ ring seals so occasionally it needs a lube which brings us nicely to the hazard of grease and high pressure air.

Know what a diesel motor is? Just about everyone does and it works by squirting a quantity of air and diesel fuel into a cylinder and squeezing it like mad until it goes pop.
Diesel fuel is the most basic of fuels, a petroleum (oil) type product aka it readily burns in the right conditions.

Unfortunately some greases are made from petroleum (oil) products and on squeezing them in a high enough pressure together with air, they do exactly the same as fuel i.e.

kaboomYou can sometimes see (and feel) this effect with spring air or gas ram weapons and funny enough it is called dieseling. I did a post about it a while ago if you are interested here [Link]

So what’s safe?
There are two thoughts here.
Grease and the innards of an air weapon are not a good mix soooo, don’t use it.
Yet you occasionally have to.
I use a silicone DIVERS RATED grease.
Nothing else and would never dream of using anything that could be a petroleum-based substance.

So is that it?
Well yes except I come back to stripping down and re-lubing a hand pump.
It’s not an easy thing to do and eventually some of the grease you use will be squirted into your much-loved PCP air weapon reservoir. From there it is a short trip into your inertia powered release valve and the breech of the weapon.

Now I’ve got caught and I guess a lot of people will be too so at that point you’ve got no choice but to strip things down and clean them. Only remember an important thing.
You can’t see air but it can sure as hell inject itself into your skin. So if you are thinking of stripping ANYTHING which uses high pressure gases or air, make sure you have drained all that force out before you start. With a PCP that usually involves dry firing the weapon until it is empty. YET THERE IS A DANGER THERE.

Some high-end PCP’s use an internal regulator to ensure you get the same pressure of puff every time you squeeze the trigger. They work by only passing high enough pressures. The danger lies that even though you keep on dry firing, the regulator won’t pass the last bit of air through it. Thus the tank may still have pressure in it even though it aint passing spit. WHAT SHOULD HAPPEN is the regulator gives up when the main tank pressure is too low for it to function and it remains “open” thus you can safely discharge your tank.
As said “WHAT SHOULD HAPPEN”. So just take care, “SHOULD” may not have happened (if you get my drift).

regulator1

 

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