Moisture. How big a deal is it?

As a noobie, I’m reading lots of stuff regarding compressors, filters, tanks, SCBA, dive shops, desiccants, fire houses, etc. I want to be nice to my expensive new hobby, but how much moisture in our air is “too much”? With moderate usage (of our guns), moderate care (a desiccant filter on the pump), moderate humidity…. How long can one expect our guns to last before they develop the “mayonnaise” problem I’ve heard described (on a website trying to sell tanks and expensive pumps/filters). Is it really that big of an issue for a hobbyist shooter?

Thanks!

Curt
 
It CAN be a big problem but that doesn't mean it WILL be if you have a halfway decent filtering system (not JUST the small 2" one that comes with most inexpensive compressors) & checking filters after running compressor. It'll give you an idea of how wet your ambient air is & allow any "cotton" material to dry. I really expected having to buy an expensive filtering system at first but the moisture here (So Cal, 4 miles from ocean) has been handled by my $50 worth of a filtering system. Can't give you a quantitative answer of "how much moisture is too much" but there haven't been an overwhelming # of posts showing extreme damage from too much moisture in guns/tanks. Kinda indicates that our filtering systems are, at least, working OK. This my opinion only! Other's experience might be different.
 
It CAN be a big problem but that doesn't mean it WILL be if you have a halfway decent filtering system (not JUST the small 2" one that comes with most inexpensive compressors) & checking filters after running compressor. It'll give you an idea of how wet your ambient air is & allow any "cotton" material to dry. I really expected having to buy an expensive filtering system at first but the moisture here (So Cal, 4 miles from ocean) has been handled by my $50 worth of a filtering system. Can't give you a quantitative answer of "how much moisture is too much" but there haven't been an overwhelming # of posts showing extreme damage from too much moisture in guns/tanks. Kinda indicates that our filtering systems are, at least, working OK. This my opinion only! Other's experience might be different.
Thanks for the input. I’m also in So Cal, and it’s usually around 50% RH here. My finger gets damp when I release the pressure in the line after pumping up my 480cc bottle. I have the little “filter” that came with my GX compressor and added a Tuxing gold one as well. Don’t want to waste money, but don’t wanna wreck my rifle either.

Curt
 
What does it cost to get set up to run nitrogen? Rent a tank from a welding place?
Nitro and tank rental isn't too bad , it is the gage and valve that is $$$ good ones i think are in the $500 or $600 range or at least what i was looking at . look up the threads we talked about this when i was thinking the same .
 
I ran nitrogen for a while but the price got stupid so I went with the Altaros booster. In my opinion, no moisture is acceptable. I live in Louisiana, most of our days are high humidity. That adds to the problem but the main source of moisture comes from the simple fact that you are compressing air. Even if you live in the desert southwest you are going to have a moisture problem. I have a series of filters that work exceptionally well and I am confident my air is dry. I had one of my guns develop a leak so I tore it down to reseal it and found no hint of moisture in the gun and I’d had the gun six years.

So to answer your question, any is too much. Hope this helps.

Mike
 
The big value in using color changing dessicant is it lets you know if you are capturing moisture and when it needs replaced. I have a second filter at least twice the size of the YH filter filled mainly with color changing dessicant. I vent the YH every 5 minutes of run time. I can fill my 45 minute tank at least 6 times before I need to change the dessicant. I have a big gold extra filter but haven't used it. I do not see a need. I change the little stock YH filter after every tank fill. I got 100 cheap from Aliexpress. Sometimes I can squeeze water out but usually I cannot. But they always have some oil trapped.

My P35s have regulators that are not externally adjustable. I've opened the air tube of the 25 caliber, the one I've owned the longest, at least 3 times and there was no sign of moisture. The 177 developed a leak so I opened it to change O-rings. Again no signs of moisture. Completely dry inside.

I do not see moisture damage as something to be feared or that is inevitable. You just need to take reasonable steps to protect your equipment and then verify that they are working.
 
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What does it cost to get set up to run nitrogen? Rent a tank from a welding place?
Here is a link to welding supply stores in your area.


If you would just buy a Bauer, Alkin or Coltri or other compressor that comes with a molecular sieve you have no worries as long as you maintenance it as required.

Some airgun manufacturers recommend scuba quality air, referred to as Grade E air. Grade D air is also fine for airguns. Fire departments that have compressors for their firefighter SCBA’s only need Grade D air. Grade D air allows slightly more moisture than Grade E. Scuba air (Grade E) is drier because moisture in a scuba regulator can cause icing when diving cold water which can result in a freeflow which dumps air quickly underwater.
It’s possible all compressors at FD’s are Grade E but I don’t know that for a fact. It’s possibly just a molecular sieve difference. I’m going to research that. I’ll make it my #2 item on my 2024 list of “to do” things. I’m curious.

The problem with your question is that everyone has an opinion and/or experience with the air they run in their guns. People that get their SCBA’s filled at dive shops or are fortunate enough to get their tanks filled at FD’s (lucky bastards) will stand behind dry air because they aren’t getting any moisture, same goes for the fortunate nitrogen guys. Nitrogen, via physics is most likely the driest.

I have only been tinkering with airguns for about three+ years. I started with a Benjamin Marauder .25 and a buddy bottle and hand pump. I got the buddy bottle filled at the local paintball shop but they would not let anyone see their setup so I had no idea what quality air they were pumping. I doubt they gave a 💩. So the limited amount of fills and then resorting to hand pumping at the range got time consuming so I bought an Omega Air Charger compressor and a molecular sieve filter/drier. About the same time I upped my game in guns too, and two 74CF SCBA’s. Then because the little addiction voice in my head said “you’re retiring soon” and will need lots more air I upgraded to the Alkin W31 dark side.
The W31 pumps Grade E (scuba) air.

You can read about users that strictly hand pump with no drying or filtering that have not experienced any issues. I didn’t feel like taking that chance. To be honest, I don’t care what anybody puts in their gun, I put dry air in mine and hopefully any problems I might see aren’t air quality related.

Dana@Mountain Air Sports recently beat the snot out of three decent quality airguns, it would be nice if he could do some testing with and without air drying tests on two identical guns to see the effect of dried air vs non-dried air. But then it also depends on your locale as to what relative humidity is at time of the testing. Way too many variables as far as I’m concerned.

So it’s like my wife, a retired RN, tells people that call her with medical issues. She tells them, “ if you’re concerned enough to ask me, talk to your doctor”. She’ll tell them what she knows, but beyond that, talk to your doctor.
Same here, if you’re worried about wet air, dry it! My PCP’s are expensive. I don’t mind working on them when necessary because of normal parts wear or finite component life, but having to work on them because of something I caused or could have prevented, that’s just dumb.

In the scuba business we had recommended service intervals that SHOULD be observed (seldom were) but that was life support equipment, airguns ain’t so all bets are off. Then there’s the cost of dry air and your budget.
 
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Thanks for the input. I’m also in So Cal, and it’s usually around 50% RH here. My finger gets damp when I release the pressure in the line after pumping up my 480cc bottle. I have the little “filter” that came with my GX compressor and added a Tuxing gold one as well. Don’t want to waste money, but don’t wanna wreck my rifle either.

Curt
The moisture you feel is the condensation from compressed air expanding into the ambient air. It doesn't generate that amount of moisture when being pumped into another vessel & being recompressed.
 
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That’s a lot of great information, everyone. Thanks mucho. I think I’m going to take reasonable precautions, including running desiccating filters, and hope for the best. I live in a fairly dry area, and I’ll be careful to keep fresh pellets and those little “cigarette butt” cotton gizmos. I plan to purchase a tank, assuming I can get it filled reasonably, and that ought to help.

Curt
 
I went to Nitrogen. Takes all the guess work out.
I’m just a little south of you (Magnolia) and was wondering about Nitrogen in our area. I have a nice Bauer compressor now, but back in 2016 just before I bought it, I called around and didn’t have any luck sourcing nitrogen. If I remember the experience correctly, it seemed like the suppliers I talked with shut down as soon as they realized I was looking for something to have at home and that I was going to be a low volume user? I dropped the idea because I stumbled upon my Purus at a killer price, but the simplicity of the dry nitrogen “air” source remains appealing to this day.
 
That’s a lot of great information, everyone. Thanks mucho. I think I’m going to take reasonable precautions, including running desiccating filters, and hope for the best. I live in a fairly dry area, and I’ll be careful to keep fresh pellets and those little “cigarette butt” cotton gizmos. I plan to purchase a tank, assuming I can get it filled reasonably, and that ought to help.

Curt
If you use a desiccant filter, refresh the beads before they get saturated, and take steps to stop liquid water from getting to the beads first (they don't do well with liquid water - it overwhelms them and they pretty much break and saturate) then you will be fine - you don't need to "hope."

Hope is for people that don't run with a desiccant filter on a powered compressor, as the desiccant is the only good way to get the water vapor out of your air stream, and the vapor is the problem. This is because the air charge is hot after compression, and air above ambient will carry vapor that condenses into water later when it cools down. That condensation, while not a lot from each fill, can build up over time and become the source of corrosion.

Use the desiccant filter properly and you won't have issues, because once the water vapor is sufficiently removed from the air stream it can't come back. Compression itself gets out most of the water (physically as a liquid) and the desiccant gets out the vapor. Together, there are no longer enough water molecules in your air charge to condense into liquid water in an ongoing way in your reservoir.
 
I’m just a little south of you (Magnolia) and was wondering about Nitrogen in our area. I have a nice Bauer compressor now, but back in 2016 just before I bought it, I called around and didn’t have any luck sourcing nitrogen. If I remember the experience correctly, it seemed like the suppliers I talked with shut down as soon as they realized I was looking for something to have at home and that I was going to be a low volume user? I dropped the idea because I stumbled upon my Purus at a killer price, but the simplicity of the dry nitrogen “air” source remains appealing to this day.

I went to Conroe welding supply and bought the largest bottle that was reasonable enough to handle which cost around $270. When it’s down to 100 psi I exchange it for around $22.
 
more likely to have problems with moisture damage to pumps, than guns ... a key concept imo, is use a pump in a climate controlled environment to start with, less moisture 'and' heat ..i monitor humidity in my house and it can be more than 50% less than outdoors .. big factor ..
Running the pump with low humidity input air definitely helps the pump - it reduces the amount of liquid water that will condense out through compression, and thus is easier on the pump. This is a very good point.

But it is important to understand that this does nothing to support having "dry" high pressure air making it into our reservoirs. Anything above an ambient RH of about 1% will leave vapor in the compressed air output, the desiccants (or extreme chillers) are needed to get that vapor out of the air that has been heated form compression. Getting that vapor out is the key for having dry cylinders.
 
Yeah, when hand pumping especially, moisture can cause serious problems.

Below, see pic of my BSA R10 where the tank corroded and broke off o_O.
Thankfully, it couldn't hold air before it completely broke off.

BSA Buddy Bottle Break.jpg
 
I’m a newbie too. Spent too much on an Airgun to mess it up. Started asking questions when I saw how much moisture I was bleeding out of my “field compressor”. I was told by Edgun west that since I’m in south Florida, I have little hope of keeping it moisture free. Luckily found a gas supplier and going to nitrogen. About $150 to rent a 300cu ft tank per year and $95 to fill. Plus about $700 for a 2 gauge regulator. It’s a 6000 psi tank. I was told I’d be able to use it til about 3000 psi. After that I’d need a compressor booster $700-$1000 to get the last 3000 psi out. We’ll see how long 1/2 a tank lasts me- probably not worth the expense for a recreational shooter.
 
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