6000 PSI Moisture Indicator -At a Cost Leaving No Guessing Excuses
Until recently, I thought it would take a multi-thousand piece of equipment to measure the moisture at 4500 PSI. The other alternative was submitting an air sample like dive centers for $200-$300 / assay. Neither were practical. So, we air gunners have been left arguing without objective data. Then I learned about this from the SCUBA forum.
https://www.augustindustries.com/shopdisplayproducts.asp?id=25&cat=Visual+Indicators
This visual moisture indicator is rated to 6000 PSI. We CAN affordably measure humidity at the pressures it matters. The whole setup including housing, indicator disc and fittings should be under $100. I’m putting it on my fill whip that has valves to seal off the indicator between uses.
I think this is perfect for owners of compressors that lack a high pressure molecular sieve filter between their compressor final stage and their equipment. Users of Shoeboxes, Omegas, Altaros, even hand pumpers no longer need rely on belief. Just add an indicator and actually know whether your output air is dry. It will also be a good way to detect when your desiccant media is expended. This is especially important if the desiccant media and indicator strip are not on the output of your high pressure stage. Desiccant in the intake or inter-compressor position will become insufficiently effective before they reach 50% saturation (when the indicator strips change color). Some blithely use just a pre-drying filter and call it a day because they don’t see water leaking out of their tanks and guns. On the other hand, there is this at http://www.brassanchor.com/hydrotest/index.html
Do you want to make that bet? Bet blindly? Well, no more betting. There is a way to objectively measure your output air humidity that every PCP air gunner can afford.
I have ordered one for my Bauer Jr, even though it has an grade-E rated separator and filter stack.
Went with a 20/40/60 disc.
The discs can even be regenerated by drying with a blow dryer. The divers replace them yearly.
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Viewing 11 replies - 1 through 11 (of 11 total)
Hi, Ray. I was wondering about the holder’s design with its flow passage so far removed from the disc. A fair amount of flow has to go by before the far end of the chamber gets full gas exchange. I was thinking about adding a baffle to force inflow to pass more directly by the indicator disc. That should decrease the time constant needed to exchange the gas in contact with the disc.
Still waiting on some more fittings and valves before making the next modification.
Please try to remember that the moisture eye was designed to be installed on a compressor with continual flow. It can take quite a bit of air flow to get that indicator strip to change. The 20/40/60 takes a little less air flow to get it to start indicating and the fastest is the 10/20/30. It is best kept under pressure so that absolutely NO outside air can get in to the card and throw off the indication. If you are installing this on a real compressor like your Junior, then it can take months for 100% of the pressure to leak down if you keep the valve shut so there is no problem with having to pre-dry the card.
I like your removable indicator idea with the QD fosters. That would make it easier to isolate the indicator between uses and let you test more than one air source.
Thanks for the excellent write-up, links and pictures! I ordered one of these this morning with enough adapters to have a male fosters on one side and a female on the other. That should let me insert it at several different points in the system (Shoebox F10/dman filter) for testing. Sounds like I might have to store the indicator assembly in a foil bag with desiccant packs between uses.
Cheers,
Rusty
One problem….
The fill whip’s thermoplastic allows eventual seepage of humidity from room air into the system. The SCUBA guys said that might be an issue. After a week of storage, there is change in both 20 and 40% segments. Looks like I need to add at least another valve to isolate the moisture indicator between uses.
Well, we know the indicator works, anyways.
Nice, and as always you are taking it to the extreme level of things. But as you already stated why bother adding more bleed points on e grade filteration system, I think the stock bleed valves are sufficient for you.
Price isn’t all that bad including shipping.
Marko
Visual moisture indicator arrived and was easily added to my Bauer compressor fill whip. With different fittings, it could be attached to any compressor’s output to objectively measure moisture content. For $100 total including shipping, you can continually check that your air is dry enough.
I ordered mine with a 1/4 to 1/4” male fitting and 20/40/60 indicator disc. By positioning the indicator proximal to my whip’s bleed and shutoff valves, I can protect the disc from exposture to atmospheric moisture between fillings. Both ends of the whip are sealed between uses and the air should remain dry in the whip.
If the indicator disc starts to turn pink, the air from the compressor output is too wet > 20%. This will warn if something is awry with my compressor’s air drying system. It’s less likely with a grade E air rated system, but on a home brew, setup with compressors lacking grade E moisture removal, this indicator can save you from tank and equipment damage. At this price, there is no excuse for not objectively knowing your final output moisture level
i also pre-bleed my whip before each fill session in case a tiny amount of moisture is condensed in the whip, I may also add a bleed valve proximal (before) the moisture indicator. That would let me protect the indicator from potential moisture in the fill whip begin cleared by the pre-bleed. That amount should be very little because air in the whip should be very dry at the end of the prior fill episode. I suspect I won’t need an extra bleed valve to protect my indicator.
Nah, don’t be. It’s frustrating at times looking at a part that I could easily buy but the cheap ass machinist in me wants to save some coin and I’m usually always in a hurry to make something I need that I could buy and save the time for something else like shooting.
Marko
That’s no fair, Marko, being able to machine and hydro test stuff yourself!
So, envious.
That’s nice, and the machinist in me thinks expensive part of aluminum being so simple to make. :winkn:
But yeah for avarage bloke, considering compressor cost and all its ok.
Marko
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That moisture eye was first designed for the scuba industry in the early 80s when compressor owners had to pack their own cartridges with filter media. Since media was so expensive, we never wanted to change it too soon. Our compressors were usually 5 CFM or bigger so air flow across the eye’s card was not a problem. The little Bauer Junior or Coltri MCH6 are regularly outfitted with eyes and it would take a tank or two to get it dried, when new since they would change color in shipping. So, we pre-dry the card with a hair drier before installing it and get going from there.
The key to keeping this operational, is to put a pressure maintaining valve somewhere on the outlet line after the eye so that the dry air is kept on the card. Having it mounted on the end of the hose by the filler isn’t a good idea either since it is anodized aluminum and big enough to provide enough leverage to possibly do some damage. Better to mount it at the outlet of your filter/inlet to hose.