GX CS4?

How hot is the ambient air you are working in? A 130 degree garage will never be as cool as a 75 degree room in the house.

If I am worried about the temp on my GX4, I stick my finger in the coolant. If I think that is hot, I close the tank and relive pressure from the system. Let the motor run 1-2 minutes with out a load and then turn off the motor...but leave the machine turned on to keep the coolant flowing.

I only fill my gun and paintball bottle, but it does seem when filling the paintball bottle from empty... The first couple thousand PSI does take some time. Topping off the tank from 2000 to 4500 goes pretty quick though.

For that tank it'll probably take 4-1/2 to 5 hours. When I filled my 9L tank from empty I ran it for about 2-1/2 hours then stopped and finished later. My workshop doesn't get too hot and the head temp on my GX CS4 never got above 55º C. GX does say the duty cycle is 4~5 hours.

I fill 45 and 60 minute tanks with the CS4. Never an issue and I do cycle the run time. 5 on 1 off. Big gold is the main filter along with a cigarette filter.

Based upon GX's 11 liters per minute fill rate, a 45 minute (6.8L) tank should take 3.2 hours from 0-4500 psi if run continuosly. This is well within the 4.5 hour continous rating for the GX-CS4. A 60 minute (9L) tank should fill from 0-4500 psi in 4 hours.

Ok, the Duning-Kruger effect has me showing my ignorance.

Cheers

JimNM said:

The pump does a pretty good job of removing moisture from the air stream. The water released when you crack the relief knob shows that. I live in the desert where 10% RH is the norm. On humid days, I will relieve the pressure more often. Keep the bottle above the pump while pumping. Keep the gun above the bottle when filling the gun.

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A low relative humidity only impacts the amount of water that will condense out of the air stream during compression - it has no bearing on the amount of water vapor that remains in the air after compression when using a powered compressor (hand pumps are a bit different, as the air charge cools more when used properly).

In order to have compressed air at 3000 psi that will have zero condensation in it after it settles to something like 70F degrees, the relative humidity would need to be less than 1% at any practical input temperature (meaning 70F or higher, with a lower value the higher it goes).

If you want to keep condensation out of your air gun reservoirs or tanks (and we all should strive to do that), you can't just rely on low humidity - you have to use an active desiccant air dryer in the line before the air gets to the tank. That is the only thing that will get rid of the excess water vapor that will still be in the air charge - regardless of how much or how little condensation was removed via traps.

Baspinall said:

So I think I should use an inline tank between my 45 min. fill tank and gun. What in line tanks do you recommend?

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Did you mean to ask what filter should you use between your compressor and your SCBA tank? If so, the large gold filters with built in replaceable/repackable cartridges are a reasonably priced effective option. If I read your question literally, I've never heard of installing a filter between a fill tank and an air rifle.

AlanMcD said:

A low relative humidity only impacts the amount of water that will condense out of the air stream during compression - it has no bearing on the amount of water vapor that remains in the air after compression when using a powered compressor (hand pumps are a bit different, as the air charge cools more when used properly).

In order to have compressed air at 3000 psi that will have zero condensation in it after it settles to something like 70F degrees, the relative humidity would need to be less than 1% at any practical input temperature (meaning 70F or higher, with a lower value the higher it goes).

If you want to keep condensation out of your air gun reservoirs or tanks (and we all should strive to do that), you can't just rely on low humidity - you have to use an active desiccant air dryer in the line before the air gets to the tank. That is the only thing that will get rid of the excess water vapor that will still be in the air charge - regardless of how much or how little condensation was removed via traps.

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@AlanMcD , you have GOT to quit posting scientific facts about moisture and compression!!

F6Hawk said:

@AlanMcD , you have GOT to quit posting scientific facts about moisture and compression!!

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I think it's useful but most people don't really understand, making statements like:

1. It OK I never get any water from the purge valve. (so the air must be dry)
2. it OK I get a lot of water from the purge valve. (so the purge must be removing most of the water)
3. I never let the compressor get hot so I don't "make" water.
4. I live in a very dry climate and only run the compressor on dry days.
5. I run the compressor inside an air conditioned room with lower humidity so it OK.
6. I use a small filter with a tampon and it's always dry.
7. I use a desiccant filter on the 1 ATM intake side of the compressor.

You can't make water unless you have a chemical or nuclear reaction. The laws of conservation of mass dictates that all the water vapor in the air ingested by the compressor either gets removing before entering your gun or tank, or it goes inside your gun or tank.

@BlackICE , @F6Hawk was just having some fun - I know he agrees with what I wrote.

I agree with your points - I have read comments like all seven of the ones you listed and I just shake my head . . .

Sadly, it is just like so much of what is going on in our society right now - people want to believe what they want to believe, and actual facts have no place in their life. Facts matter. And in our hobby, if somebody compresses air with a powered compressor, water will be condensing out into liquid in the destination reservoir if the air charge is not actively "dried" with an appropriate desiccant filter (or a chiller that cools the air charge below ambient use and then passes it through a coalescing filter - but a desiccant is easier and probably cheaper too). That's a fact, derived from the actual physics of the situation (I know that you both know this . . . written for others that read this).

BlackICE said:

I think it's useful but most people don't really understand, making statements like:

1. It OK I never get any water from the purge valve. (so the air must be dry)
2. it OK I get a lot of water from the purge valve. (so the purge must be removing most of the water)
3. I never let the compressor get hot so I don't "make" water.
4. I live in a very dry climate and only run the compressor on dry days.
5. I run the compressor inside an air conditioned room with lower humidity so it OK.
6. I use a small filter with a tampon and it's always dry.
7. I use a desiccant filter on the 1 ATM intake side of the compressor.

You can't make water unless you have a chemical or nuclear reaction. The laws of conservation of mass dictates that all the water vapor in the air ingested by the compressor either gets removing before entering your gun or tank, or it goes inside your gun or tank.

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I know buddy, I was playing with @AlanMcD because he has posted about moisture and its removal MANY times on this forum, and it seems the majority of members either haven't read it, don't understand it, or ignore his mentoring.

Without a tremendous amount of expense, all compressed air will will contain water, period. As a SCUBA diver who has a regulator that has a reed valve that takes advantage of this fact by condensing the water to help prevent dry mouth, I know that even "uber dry" SCUBA air has water in it.

Alan is one smart cookie when it comes to compressed air. Now whether or not he know his way around a smoker/grill, I cannot say.

F6Hawk said:

I know buddy, I was playing with @AlanMcD because he has posted about moisture and its removal MANY times on this forum, and it seems the majority of members either haven't read it, don't understand it, or ignore his mentoring.

Without a tremendous amount of expense, all compressed air will will contain water, period. As a SCUBA diver who has a regulator that has a reed valve that takes advantage of this fact by condensing the water to help prevent dry mouth, I know that even "uber dry" SCUBA air has water in it.

Alan is one smart cookie when it comes to compressed air. Now whether or not he know his way around a smoker/grill, I cannot say.

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HUH!!??
What's this about smokin' PCP while drying the air in your gun on the grill?

F6Hawk said:

I know buddy, I was playing with @AlanMcD because he has posted about moisture and its removal MANY times on this forum, and it seems the majority of members either haven't read it, don't understand it, or ignore his mentoring.

Without a tremendous amount of expense, all compressed air will will contain water, period. As a SCUBA diver who has a regulator that has a reed valve that takes advantage of this fact by condensing the water to help prevent dry mouth, I know that even "uber dry" SCUBA air has water in it.

Alan is one smart cookie when it comes to compressed air. Now whether or not he know his way around a smoker/grill, I cannot say.

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I'd also add that in spite of lots of great info being put out here, many folks don't know the difference between a 45 min SCBA tank (a fire fighter rating which is HUGELY variable based on stress, lung capacity, etc.), a 9L tank, cu in of water volume, and cu ft of air volume. SO many terms being compared, and often times incorrectly.

For example, a 550 cu in tank (water volume) is also a 9L tank (direct calculation because it's water volume. But that tank is commonly called a 97 Cu Ft tank, because it holds roughly 97 cu ft of AIR at 4500 PSI. But what if the pressure is only 4000 psi? Suddenly, it's an 86 cu ft air tank.

Air measurements, as well as minutes of breathing time, are VARIABLE ratings. Water volume is CONSTANT. A person telling us he fills his XX cu ft tank in HH:MM isn't really helping, unless another person is trying to fill that same 9L tank to the exact same pressure.



As an example to what I am trying to explain, that 9L, 550 cu in, "60 minute", "88 cu ft" tank is also referred to as a "90 cu ft", "95 cu ft", as well as "97 cu ft" tank. Why? Because air voulme VARIES. As does breathing time. The hard numbers to remember are the two left-most columns.

This is a great thread. Some really good info. Having worked the dive industry and fire service and their absolute requirement for dry air for reliable equipment function, dry air is imperative. There are a lot of people with solid empirical evidence/experience that they do not have moisture issues, that they are aware of. A lot of the time I think it comes down to “seems to be working fine”. And that’s fine, it’s not like it’s a fire fighters SCBA in a burning building or a scuba diver at 150 feet in 42° water. Bad things happen when you want air and it’s not available. If their air gun ceases functioning it’s just an inconvenience.
I think the majority of the time it’s a matter of budget, just trying to limit the amount of cash it takes to send pellets downrange. And we all understand that.
Black Ice, nice list, I think you really hit the nail right on the head.