cleanest PCP air source / supply

cleanest PCP air source / supply

Joined: April 23rd, 2013, 8:07 pm

June 17th, 2017, 8:50 pm #1

Friends,

I'm starting from zero PCP equipment and looking to figure out what will give me the cleanest air. I'm thinking (in order of most clean to least clean with the understanding that the difference between 1 & 4 might not be substantial):

1) scuba shop fill
2) nitrogen tank rented from welding supply shop
3) professional dive compressor from a reputable source
4) Shoe box or similar with appropriate filter
5) hand pump

All options would be used with a carbon fiber tank (with the exception of 5). I'm not considering a hand pump but listed it only as a point of reference.

I'm not trying to criticize any given equipment or set up but I am trying to get educated and confirm my assumptions. Why? Because I plan on getting back into PCP and would like to minimize maintenance and/or down time caused by liquid or debris in the mechanism.

Thanks for your advice!

Joe
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Joined: May 27th, 2017, 11:49 pm

June 17th, 2017, 10:44 pm #2

I am partial to the N2 from the Welding Supply shop. Coming from a semiconductor fabrication background I trust bottled gas more than other sources. It will likely be cleaner and drier than other sources (and should be certified as such) since it has to be pure and dry for welding. I have 2 6K bottles and have never used air to date.
N2 will produce just a bit more power than Clean Dry Air but the amount of extra power may be imperceptible. Any time you can eliminate oxygen from the mix you also eliminate oxidation within the pressure vessel (corrosion and or rust). I shoot a lot and use about a cylinder a year. I will also say it is likely the highest price option in the long run.
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Joined: April 23rd, 2013, 8:07 pm

June 18th, 2017, 3:00 am #3

Thanks T3P - excellent info! nt
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Joined: May 6th, 2010, 4:26 pm

June 19th, 2017, 5:06 pm #4

Friends,

I'm starting from zero PCP equipment and looking to figure out what will give me the cleanest air. I'm thinking (in order of most clean to least clean with the understanding that the difference between 1 & 4 might not be substantial):

1) scuba shop fill
2) nitrogen tank rented from welding supply shop
3) professional dive compressor from a reputable source
4) Shoe box or similar with appropriate filter
5) hand pump

All options would be used with a carbon fiber tank (with the exception of 5). I'm not considering a hand pump but listed it only as a point of reference.

I'm not trying to criticize any given equipment or set up but I am trying to get educated and confirm my assumptions. Why? Because I plan on getting back into PCP and would like to minimize maintenance and/or down time caused by liquid or debris in the mechanism.

Thanks for your advice!

Joe
I think your table looks right, although one could argue the relative ranking of #1 and #2 (and of course #2 is not "air" anyways).

I think handpumping can also be split a bit too - different pumps have different filtration capabilities, and the biggest swing here is in the process the user chooses to follow - how many strokes in a session and the like . . .

To mean the real question is why do you ask? I spent quite a few years each with a Hill pump with Drypac (#5), then a tank filled by a dive shop (#1), and then a tank filled by a Shoebox with a good filter system before the unit but not after it (#4), and I can say this: I have never seen any difference inside my guns when I have torn them down for any maintenance or modifications. No signs of dirt, moisture or anything like that.

So in the end, if you do things "right" with each method, what difference does it make?
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Joined: April 23rd, 2013, 8:07 pm

June 21st, 2017, 9:46 am #5

Alan,

Thanks for the info and it's good to note that you never noticed any issues with your equipment even with a pump. I'll be retiring soon in the East Texas area and our humidity at times can be pretty high. In effect, moisture is a concern as well as frequency of filter/filtration system changes.

"... the real question is why do you ask?" In short, I'm just doing some research on how to keep my equipment in top shape by using the cleanest air possible.

Joe
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Joined: May 6th, 2010, 4:26 pm

June 21st, 2017, 11:37 am #6

When I was using the handpump, I made sure that I changed Hill's Drypac beads on a regular basis. When not in use (when I was done shooting for the day), I took the Drypac off the pump and stored it in a ziploc bag - that stopped it from getting saturated from vapor in the ambient air (probably a bigger issue for you) - which is important as the Hill beads are molecular sieve which are not "indicating" beads, so you can't tell when they are "used up." But they trap water vapor much more effectively than silica beads do.

Also, I had read somewhere online that Hill's testing of the desiccant showed that the air got drier after a few pumps, meaning the air in the line had more moisture in it than it would have later. With that in mind, I always set it up and took a few strokes pumping air through the handpump before hooking it up to the gun and charging the line to minimize the water vapor in the system.

And I always limited my pumping sessions to about 50 strokes (plus a few to get the line charged on the fill), pausing for a second or two at the bottom of the stroke to give the air charge a little dwell time in the base for cooling. If the air is cool coming out of the pump (which it will be if you pump in short sessions) it won't be able to carry much water vapor into the gun.
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