Moisture in the tank.

[Blowpipe Sam]

I live on the gulf coast where it is pretty humid year round.  I fill my PCP’s with a hand pump.  Every third time I fill a gun I put two to three drops of synthetic oil down the adaptor or foster fitting.  I generally fill my guns in the mid afternoon when the relative humidity is lowest or in the evening when it can be a good deal higher.  My guns are stored muzzle up and I usually shoot two or three dry firings straight up to purge any water that might have condensed in the reservoir overnight.  Sometimes water vapor is evident at the muzzle for two or three shots when the gun is dry fired straight up like this.  My pump does not have a moisture trap and I’m not sure one would even work on it.

Does anyone else have concerns about moisture in the gun?  I know there are moisture traps available for compressors.  Are there any for hand pumps?  Does anyone else purge their PCP’s?

[maraudinglizard]

This will help with the moisture in hand pumps. I run my air compressors in my shop to reduce the moisture intake. The compressors came with internal moisture traps and I also use an inline filter as well. 

https://gatewaytoairguns.org/GTA/index.php?topic=178950.0

[Blowpipe Sam]

Thanks Kris.  That actually gave me an idea about how to use our big electric household dehumidifier to dry the air prior to pumping it into the reservoir.

[Back_Roads]

 If one does not let the rifle get below 2000 psi, the act of bringing the pump up to gun pressure will wring 98% of the moisture out, the small cotton filters are there to absorb the droplets basically. Hand pump bleed offs have enough reservoir to catch most of it also.
 Moisture coming out of the barrel may just be the cooling effect of the air escaping when fired, and the ambient air is humid and condenses around the cool blast.
 

[Van]

I have a China pump with the inline add on gold filter.  I pump several Discos up to 2500psi sometimes since they are modded to take that much.  I have never had any moisture in the filter, pump bleed off or seen any in the gun when I take one apart.  I too add some silicone oil to the fill nipple occasionally to preserve the rubber seals and pump almost always indoors in climate controlled shop. Lately I just took off the inline filter since I did not see the need for it used indoors.  I think adding the oil every 3rd or 4th pump up is why I never have any gun leak down.

[Blowpipe Sam]

Thanks folks.  I’m shooting entry level PCP’s that shoot well below 2,000 PSI and I live in a subtropical swamp.  It is definitely moisture coming from the muzzle.  I held some brown packing paper next to the muzzle and got a damp spot.  It’s not oil because it evaporated in a few minutes.  Only lasts for that first couple of shots.  I’m concerned about moisture in the reservoir and valve causing corrosion.  Don’t know if that’s a real problem or not.  I’ve got a plan to provide dry air from the dehumidifier to the pump intake that should be effective but I will still purge my PCP’s occasionally.

[Back_Roads]

 I did alot of hand pumping in climate controlled environments in the past

[Deadrise Skiff]

I got a lot of water in my hatsan flash R last month with a hand pump.
Filling up to the 250 bar makes a lot of heat, and I am not very scientific, but I felt the air tube getting warm,
and it may possible causing condensation between the heating then cooling of the air.
I took the air tank off to adjust the regulator, and there was rust between the aluminum regulator and the air tanks steel walls.
There were many water droplets along the way up & down the tube.
I have a dehumidifier set t 50% in the room I pumped in..
I now pump a small amount at the time to keep the heat lower, and have since removed air tank & looked inside to find it dry.

[JPSAXNC]

I also put a short piece of pipe cleaner in the quick connect that attaches to the gun. To stop rust and other debris from going in the gun.

[airgunaut]

Some of you might have read this, but for those who have not...

https://hardairmagazine.com/reviews/warning-distressing-content-pcp-airgun-corrosion-this-is-what-moisture-does-to-your-air-rifle/

[Doug Wall]

If you are getting moisture coming out ok the gun, then you are getting moisture in the gun high pressure moisture in the gun means corrosion on aluminum parts, like valves. Put a large desiccant filter on the input side of the pump!