Page 1 of 2 12 LastLast
Results 1 to 15 of 26

Thread: Moisture in PCPs

  1. #1
    Sharp Shooter
    Forum Sponsor

    User Info Menu

    Default Moisture in PCPs

    Hey guys. So this is specifically a question for those guys using a hand pump WITHOUT a moisture removal device (hills dry pac etc). What effect does storing air long term in the cylinders of say a Artemis P15 have? Can it cause rust buildup? If so can this lead to sudden failure such as a burst after prolonged periods? Is there anything that can be done to prevent this? (silicone oils or lubricants added?) if so how? Also can the artemis p15 cylinder be depressurised when not In use?
    Cheers
    S
    Sign Up To Air Rifle SA Forums

  2. #2
    Sharp Shooter

    User Info Menu

    Default

    I don't know about the P15 but when you compress air its ability to hold water vapour (humidity) is reduced so some of the water vapour condenses to form water droplets.

    Water will react with oxygen to corrode exposed metal surfaces. In the case of iron or steel specifically it forms rust. In aluminium alloys it can form a white powder. Brass, bronze and copper are also affected but less so.
    Where different metals are in contact with both water and each other another form of corrosion (galvanic corrosion) can occur which often causes pitting in metals.

    Due to high pressure of air, the oxygen in that air is also at higher pressure than our normal surroundings. The higher oxygen pressure causes corrosion to occur faster than it would in our normal surroundings. The presence of water and dissimilar metals in contact (galvanic) also accelerate corrosion. So the inside of the pressurised parts of your PCP can get corroded faster than you would think.

    What can you do ?
    1) oil based lubricants are a no-no. They certainly inhibit corrosion but in high pressure air they can also ignite or react with the high pressure oxygen causing explosion or fire or heat damage.
    2) many of the parts in your PCP may be painted or anodised. This provides protection except where the metal has been machined (e.g. for threads or o-ring grooves) or where moving parts expose fresh metal.
    3) non-flammable oils and greases like silicone can help. Not so sure about moly greases...I need to read up on them a bit.
    4) corrosion resistant metals like stainless steel, titanium and brass are not going to be affected much. If your air tank parts are made of these then you can probably relax.
    5) drain the air (and water) when you're done shooting and store depressurised
    6) get an air drier for your hand pump. It doesn't have to be high pressure rated. A chemical drier that you attach to the pump intake will help. There are various commercial types.
    7) if you live in a very dry climate then probably not much to worry about.
    Sign Up To Air Rifle SA Forums

  3. #3
    Sharp Shooter
    Forum Sponsor

    User Info Menu

    Default

    Many thanks for the comprehensive reply. Much appreciated. from what I've read the cylinder is titanium. I've got some silicone oil and moly grease for the other parts.
    Sign Up To Air Rifle SA Forums

  4. #4
    Sharp Shooter
    Forum Sponsor

    User Info Menu

    Default

    Best is to put a drop of HYDRAULIC Oil in the inlet valve an pump it into the cylinder.
    Sign Up To Air Rifle SA Forums

  5. #5
    Sharp Shooter
    Forum Sponsor

    User Info Menu

    Default

    Quote Originally Posted by MikeBrews View Post
    Best is to put a drop of HYDRAULIC Oil in the inlet valve an pump it into the cylinder.

    I've got a little tube of pellgunoil. Will that suffice?
    Sign Up To Air Rifle SA Forums

  6. #6
    Sharp Shooter
    Forum Sponsor

    User Info Menu

    Default

    That's for outside use. Use Hydraulic oil for inside the pressurized cylinder. .
    Sign Up To Air Rifle SA Forums

  7. #7
    Sharp Shooter

    User Info Menu

    Default

    Best is to upgrade to a scuba tank if you can. Dry air. However, some forum members live far away from a source of refills so not workable for them.
    Sign Up To Air Rifle SA Forums

  8. #8
    Sharp Shooter

    User Info Menu

    Default

    I once read a proper article on Pyramydair regarding moisture in PCP guns. I cannot find it now. But the one below it is said any moisture will be shot out in a few shots.
    https://www.pyramydair.com/customer-...tic_Stock/3139
    Sign Up To Air Rifle SA Forums

  9. #9
    Sharp Shooter

    User Info Menu

    Sign Up To Air Rifle SA Forums

  10. #10
    Sharp Shooter
    Forum Sponsor

    User Info Menu

    Default

    Ah ok. Available from auto parts stores like midas etc?
    Sign Up To Air Rifle SA Forums

  11. #11
    Sharp Shooter

    User Info Menu

    Default

    Quote Originally Posted by TwentyCal View Post
    ........But the one below it is said any moisture will be shot out
    When you fill your rifle with air compressed from atmospheric pressure to say 200 bar then almost all the humidity in that air will condense to water which lies in the bottom of the rifle's air tank. When you shoot, some of the water might get carried out with the air. Also, as the air is consumed the pressure will drop and some of the water will (slowly) evaporate back into the air. But since most rifles don't shoot much below 100 bar or so, most of the water will not re evaporate.

    I've seen pics of rusted PCP internals but I suspect it took quite a few years to cause problems.
    Sign Up To Air Rifle SA Forums

  12. #12
    Sharp Shooter
    Forum Sponsor

    User Info Menu

    Default

    ok so from all the reading, advice and thread posts etc that you guys kindly posted it seems that a burst is VERY unlikely. a drop of silicone or hydraulic oil is fine to use if you do want to lube. but never mineral based lubes or greases. makes sense.
    Thanks guys :
    Sign Up To Air Rifle SA Forums

  13. #13
    Sharp Shooter

    User Info Menu

    Default

    Quote Originally Posted by JXV View Post
    I've seen pics of rusted PCP internals but I suspect it took quite a few years to cause problems.
    My one PCP is more than 12 years old. I just hope there is no rust.
    Sign Up To Air Rifle SA Forums

  14. #14
    Sharp Shooter

    User Info Menu

    Default

    Warning Distressing Content! PCP airgun corrosion - this happens to your air rifle!

    This is an article from Ham Air Magazine. Maybe they are trying to drum up sales of driers or maybe its genuine. Decide for yourself. Remember the cheaper pcps are less likely to have exotic corrosion resistant materials.
    Last edited by JXV; 23-08-19 at 11:46.
    Sign Up To Air Rifle SA Forums

  15. #15
    Sharp Shooter
    Forum Sponsor

    User Info Menu

    Default

    interesting. that shows some bad corrosion on the alu parts.
    I have a Hatsun pump that has no dry air filter. has anyone made a homemade filter of sorts to fit to a pump that has no dry air filter?
    Sign Up To Air Rifle SA Forums


Similar Threads

  1. Yong Heng moisture trap
    By Nick V in forum Airgun Discussions
    Replies: 3
    Last Post: 25-04-19, 20:58
  2. Beware The Moisture
    By KGB in forum Airgun Discussions
    Replies: 22
    Last Post: 18-04-13, 10:23
  3. Replies: 9
    Last Post: 11-07-11, 20:26
  4. Compressed air Vessel. Moisture?
    By goose in forum Airgun Discussions
    Replies: 10
    Last Post: 05-01-08, 23:20

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
Friends of Air Rifle SA