How to fill a PCP with a scuba tank?

newgunboy

newgunboy

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Hey all, I'm looking at buying a PCP (Marauder or other) and they don't seem to come with a way to fill them included. I already have a scuba tank so I'm looking at using that but I need some advice on what kind of gear I need to get the air from the tank to the gun.
Any recommendations on what brands/models and Canadian dealers I should look at would be great.
Thanks in advance.
 
While I don't know what a Marauder air rifle requires fill pressure wise, I do know that an air tank made for SCUBA diving will be next to useless for PCP use. They are heavy, have the wrong valve fittings, and cannot hold the pressures required for a modern airgun. The only 'good' thing about a SCUBA tank is that as long as it is fully approved and within the date limits, one can get it filled at a diving shop to about 2200psi if I recall properly. With some effort, fittings can be found to allow some limited use of such. Overall though, it is better to invest in a few pieces of reasonably good gear like a carbon fibre wound tank, a high pressure valve, and a high pressure hose. Unless you pay for DOT or equivalent rated tanks, you will NOT be able to fill it from anywhere but your own pump. I can almost guarantee that you will choose some sort of electrical high pressure pump for this task. While a hand pump can be purchased, it gets old really really fast. Modern PCP guns usually need supply tanks holding 300Bar (30MPa, ~4500psi) pressure with a 2-9 litre capacity. The higher the capacity, the more refills of your air rifle bottle before the big fill tank's pressure is insufficient. Unfortunately, filling such a tank can take a very long time indeed and will require an air pump capable of supplying very high pressure. So, my suggestion is google. Search for and watch videos discussing all the various parts and how they fit together. As a quick take-out, for the most part, current carbon fibre wound HPA (High Pressure Air) tanks are pretty much all made in China or Europe. The female threading is almost universally female M18-1.5. So you need a male M18-1.5 threaded valve assembly to screw into them. Some valves have HPA regulators built in to drop the tank pressure to the required airgun bottle pressure. On the output side, quick connects are the gold standard to connect the output from the valve assembly on the HPA tank to teh airgun bottle. They can handle the pressure reliably and are easy to use. The rifle end of things also use quick connects either directly or indirectly through probes specific to the airgun. This is pretty straightforward. Filling the tanks is where the issues usually occur. There are lots of HPA air pumps out there. A good number are marginal to total crap, others are ok, some are pretty good, a few are excellent. That progression is pretty much directly related to wallet capacity.
 
There are lots of tank styles out there but generally you need: a yolk, high pressure "T", high pressure shutoff valve for line purging, high pressure hoses with proper crimped ends and maybe thread adapters. You may need a regulator and gauge depending on the relative fill pressure of your SCUBA and PCP tanks. What style valve is on the SCUBA? DIN 300 or CGA 347? Finding out the HPA connector style on the PCP is also important since many fittings look similar but can cause very dangerous situations when pressurized to 4K+psi.
 
Scuba shops will not supply the pressure needed for most PCP's. Mine requires 3600 psi for a full charge... if I am filling a supply tank it is filled to 4500 psi.
Most PCP's come with a fitting for filling... you just need to screw the appropriate supply to that fitting.
 
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Here's an older pic and the lay out of how I plumbed my dryer.
Only thing missing is the 5 gal pail of coolant/wtr pump to keep the compressor from melting.
The tank is a 1hr Scotts scba rescue 4500psi.

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pump.jpeg
 
This is for the op... every pcp be it a rifle or pistol uses a charging fitting specific to it. Pictured are two fittings, one for my rifle and one for my pistol. a quick coupler from the supply fits the one end of the fitting, the other end fits the specific pcp.

IMG_0193.JPG
 
I am a large volume - BR shooter, I built this fill station around my needs ...

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Filling or refilling to 300 bars my 3 scba tanks about ones a month, and one is always fully charged for case of emergency.
If I would start from fresh with this my learning curve, I would buy a largest DOT carbon fiber tank (or two) and pay a yearly membership in a dive shop. I have two shops around me both can fill to 4500=300, and if I can recall correctly they were chargin about $50-80 per bottle /year.
 
bigHUN said:
I am a large volume - BR shooter, I built this fill station around my needs ...

View attachment 841681

Filling or refilling to 300 bars my 3 scba tanks about ones a month, and one is always fully charged for case of emergency.
If I would start from fresh with this my learning curve, I would buy a largest DOT carbon fiber tank (or two) and pay a yearly membership in a dive shop. I have two shops around me both can fill to 4500=300, and if I can recall correctly they were chargin about $50-80 per bottle /year.
Click to expand...
I'm just starting out with airguns, hopefully will find a local club for benchrest, as I've just recently been awakened to their capabilities.

For Field target you are limited to 20ft/lbs so when I tune my rifle down to that I get over 400 shots per fill.
480cc on the rifle tank and only using 35 bar for 13.14gr .22 pellets.
So the cheap jumping compressor is more than adequate for that. With a filter similar to the ones you are using.

For me driving to and from a dive shop is over 2 hours. Yeah doable, but also adds another todo list item. Lol

I think I follow which machine and your setup there. Something similar to what I was thinking of setting up, and I've seen threads of that similar setup just being beaten on so they seem ok.

So from your experience what would you recommend to a person that is thinking about buying a large tank (maybe not carbon fiber as not hauling it around much) and planning in their head to build a contraption similar to yours. :)

What are you using to shoot benchrest?
 
If you just starting up and you have not invested yet... I would recommend getting some larger scba tank or two.
Back in a time (2018-19) I got these from a firestation auction sale for I guess about $150 total ??

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Or, there are smaller 2-3 Liter CF tanks for paintball guns, maybe you can grab some from kijiji or craigslit.

A next step up is getting a compressor, but be prepared for the price for supporting accessories can exceed the the YH piece price easily.
I don't know where you live, but at my place (North of Toronto, between the big lakes) I have humid all year around, winter-summer.
If you want to save your airguns and equipment you better invest into a serious oil/water separator like mine in the picture earlier... no cheap solutions could work only hassle will pile up.
I got this mine filter from aliexpress, when you start using it it is an eye opening how much moisture it is removing.

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The first stage is mechanical, no media to replace. The second stage has media, it came with active carbon for breathing air but I have not replace it for fifth year already.
You single - or dual - stage filter shall look like this when you search for it:

1809B4EB-C71D-482B-A164-E3092E72F8A6.png
 
My Hatsan pcp performs best when filled to 2000 psi. I use a scuba tank with a yoke and pressure guage to fill it. The yoke and hose was pretty cheap. The rifle came with the adapter to fit the fill mechanism on the rifle. When my scuba tank is first filled by the scuba shop, it is filled to approx 3100 psi. It is a standard aluminum Faber scuba tank. I get many fills from a tank. When the tank pressure goes down to around 2000 psi, I can then shoot from the bench, with the tank attached to the rifle, fill valve open, and get very consistent velocities.
 
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Usually I am re-filling my tanks from 200 bars to almost 300 bars, but when the tank cools down the pressure drops anywhere about 280 ish.
These my 14 Liter scba gives me roughly about 7-800 shots, but I never actually counted, only seeing the empty tins.
Always using one tank first, the others are full and ready to go.
Usually about every 3-4 weeks I am refilling as much needed, and that is a 2-3 hours workparty, I am really paying attention to cool down the compressor and the tanks.
 
Thanks guys! It's these little details sometimes that saves jumping too early or in a wrong direction.

I have experience with industrial compressors but only to 150psi.
Strapped on a scuba tank but never filled one.

I have seen on some of those setups they also put copper tubing around the hp tubing,
from what you describe the cooling of the air after compression is a nice to have vs a must have when doing a few tanks.
It may save 20 bar cool down loss on the tanks.
Same thing I see when I fill my 480cc tank.

Sometimes it's hard not to know haw far to chase things down the rabbit hole.

I had thought about getting a second filter housing and just using it as a water trap,
if it would really save the media, makes sense that it does for you.

Always looking to try and save a drive and save a buck these days.

Lol I'm just glad I didn't buy a hand pump first.
 
Just to clarify one thing here.
You can try to cool down the steel tubes on the compressor, worth a try, but still the whip lines, the water separator will heat up = from a pressure.
And can't do nothing else with the tank at the end... the air tank will heat up, not very much but you can feel it with your touch.
Both the tank + the compressor motor also the oil, you will need to cool down with frequent stops.
 
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