Moisture filter question

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Corvid_hunter said:
I have a inline moisture filter for my pump. It currently has the tubular cotton filters in it. Can I just remove them and pour in some of the replacement moisture media? I'm guessing I would need to to leave one of the tubular ones in at the inlet and one at the outlet side to keep the beads in place?
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I do and it seems to work fine, but I am definitely not an expert with pumps and filters.
 
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My concern would be corrosion from having moisture media, combined with trapped moisture, in direct contact with aluminum. Molecular sieve filters use a plastic insert to separate chemicals from cylinder walls. WM
IMG_20221022_234748.jpg
 
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I cut a 1/2" piece off the cotton filters & then cut that in half to create 1/4" plugs at each end of the filter housing after putting in better drying media. Works just fine. Mainly to filter any dust or particulates from the silica beads my filter is filled with. I stopped using charcoal & fill the whole tube with silica beads. After using compressor I always open my filters to allow air drying of filter media.
 
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WorriedMan said:
My concern would be corrosion from having moisture media, combined with trapped moisture, in direct contact with aluminum. Molecular sieve filters use a plastic insert to separate chemicals from cylinder walls. WMView attachment 532065
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I use one very similar to this one 👍. Got mine from amazon and it came with an extra pre-filled insert and you can purchase just the pre-filled inserts.
 
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AlanMcD said:
You could make a plastic liner for yours out of some of the plastic that is used for transparencies - cut it to the right length, then roll it up and tape it to the right diameter/shape. Then use the filters (cut as already described) as end plugs with the beads in the center. It should work fine.
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A member recently explained why plastic insert only has "O" ring on one end (you can see this in M50 Instruction Manual photo.) Seems pressure needs to equalize between plastic insert and aluminum housing to prevent insert collapse. Always appreciate learning new things on this forum. WM

EDIT: Thanks to JackHughs for the explanation!
 
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If you want a good water-oil separator, you need to look for these mechanical filters, single or dual stage.
No media in this one, will work for a lifetime.

1809B4EB-C71D-482B-A164-E3092E72F8A6.png


Back in 2021 I bought myself a two stage, in first cylinder a centrifugal filter and media in second (in four years never needed replacement).
A lot of humid at my place especially over summer months.
 
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bigHUN said:
If you want a good water-oil separator, you need to look for these mechanical filters, single or dual stage.
No media in this one, will work for a lifetime.

View attachment 533678

Back in 2021 I bought myself a two stage, in first cylinder a centrifugal filter and media in second (in four years never needed replacement).
A lot of humid at my place especially over summer months.
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Just purchased my first air rifle and now looking at air filters to combo with a GX CS4. I've looked at this very filter and I definitely like the idea of it since Arkansas has high humidity at times. I see you mentioned a two stage as well. Are you referring to running a separate molecular sieve filter after the centrifugal filter? This is the setup I'm gravitating to and trying to get all the necessary parts together.
 
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This what I have. I was searching for it recently for a friend and not seeing it currently at aliexpress.

20250130_082805.jpg


The right side tower is the mechanical filter, the left side is the media filter.
In the very first days I tried to open the tubes just to see what is inside.
The right side - mechanical is factory sealed, I could not even start to loosen it and I left it as is not to break it.
I could successfully open the left side tower, and there is the active carbon filter inside. I did not replace mine yet in all these years. I bought a bag of desiccant just to make sure, but still in original bag sitting in the closet for years.

water separator filter - Capture.JPG


The "first stage" works very well, I have not seen many times only a few drips coming out from second stage. My place (in Toronto) is humid winter-summer. Right now -12C and 85%, with 4KW electric (construction) heater running in my garage during days is 45%.
 
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Thanks for the explanation. I had tried to look up something like this and the only thing I could find had a cotton filter first stage ahead of the media filter. I like the idea of the mechanical filter better. The second stage probably isn't needed, but I'm paranoid and would rather have it there just in case (as it's now at 56F/13C with 99% humidity in my area). Probably going to rig it up how your unit is with two separate filters and call it done.

Do you have a check valve and other purge valves in your air system? I've read where those can make filling a bit easier as you don't have to worry about the compressor line being pressurized and it can ramp up. For now I'll be filling the gun directly, but hope to get a fill tank once I recover from these initial purchases.
 
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trailhiker21 said:
Thanks for the explanation. I had tried to look up something like this and the only thing I could find had a cotton filter first stage ahead of the media filter. I like the idea of the mechanical filter better. The second stage probably isn't needed, but I'm paranoid and would rather have it there just in case (as it's now at 56F/13C with 99% humidity in my area). Probably going to rig it up how your unit is with two separate filters and call it done.

Do you have a check valve and other purge valves in your air system? I've read where those can make filling a bit easier as you don't have to worry about the compressor line being pressurized and it can ramp up. For now I'll be filling the gun directly, but hope to get a fill tank once I recover from these initial purchases.
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Start your compressor with the bleed valve open. Then close the bleed valve but don't open the tank valve until the filters are pressurized. The issues with multiple large filters are: (1) the compressor run time it takes to pressurize the filters and (2) the loss of all that air when the system is bled. I have one large Tuxing cartridge filter on my CS4-I. It takes five minutes for the compressor to pressurize that filter to 300 bar.

JackHughs
 
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Yeah I understand what you are saying, but since I don't have a tank and will be filling the gun direct, would that change things? Also curious if there's a reason why you couldn't leave your filters charged for a day while you are using it frequently. This would obviously require check valves on both sides of the filter and a proper bleeding process to depressurize when finished, but my thought is that this would save you that 5 mins every time you want to top off the gun. Then again, doing all of this might end up adding up to the cost of a small storage tank...
 
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If you have the proper one-way valves and pressure relief at the gun end you can leave the filters pressurized all the time! I check the water separator after each fill, just enough to see if there is any water. I just checked my indicator beads and changed them but before that the filters were under pressure for 4 months.
If you draw yourself a diagram you will find that you need an on-offer valve as one-ways alone don't do it.
 
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trailhiker21 said:
Yeah I understand what you are saying, but since I don't have a tank and will be filling the gun direct, would that change things? Also curious if there's a reason why you couldn't leave your filters charged for a day while you are using it frequently. This would obviously require check valves on both sides of the filter and a proper bleeding process to depressurize when finished, but my thought is that this would save you that 5 mins every time you want to top off the gun. Then again, doing all of this might end up adding up to the cost of a small storage tank...
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I leave the tanks on my guns pressurized for months at a time. So, all things considered, I guess it would be OK to leave the filters pressurized for a day or two - something to consider.

JackHughs
 
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