Diving Tanks

[bravozullu]

Been a Diana / tempest / Feinwerk P80 /spring plinker for 50 yrs.. on and off. and some other classics. OK, i am behind the times but happy with what i had.
Might branch into PCP after learning about "what is available"
I hand one question for now. I was once a diver and neglected to dispose of my two air tanks. Big and heavy.
I realize it would take a life time to charge them with a hand pump ... but is it practical to use them with an
electric pump and then feed a PCP from them? One fellow commented that it was a @#!@$ idea. If so fine OK I will accept his comments but
he did not give me any reason. One reason on the surface ... darn heavy to carry around in the field.
So starting my journey. Not purchased any PCP yet. Just beginning my learning process.
Yes... those springers are very old but still are accurate at paper targets.
VR
Michael

 

[WorriedMan]

Michael,
Not a tank guy but from what I've read, SCBA tanks hold higher pressures than SCUBA. Depending on choice of PCP, SCUBA might not allow one complete refill. Upper right corner of page type, "SCUBA," search might help clarify. WM

 

[Keyman62421]

I think WM is probably right you won't have enough tank to run a modern PCP .
I did and would buy a GX CS4 you can fill any gun you want and smaller tanks to medium tanks. that's my advice.

 

[John "spysir" Blount]

Hand pumping? No. Figure about 1cc per stroke not counting filling the line, bleed & cool every 50 or so pump. My old 490cc Ultra 9mm took 500 strokes from empty, times that by feet & oh my. It "could" be done tho.
Any chance they say "If it's HEAVY ( maybe it said steel?) i's a Faber?
I had a 100cf Faber rated at 3,4500psi and the shop would hot fill 10% over. worked well for all target rigs. Also if Faber they Are worth money! Get them inspected, sell them and you have enough for a modern SCBA, but fills? Around here Faber's go for around $300 for just the tank.
A 3,000psi aluminum tank would work depending on what pcp you are thinking of.

Hand pump's are excellent for rifles only. Something like a Crosman Challenger would be easy pumping.

John

 

[rcs9250]

There are some 10 meter rifles that use 3000 psi aluminum tanks, Anschutz comes to mind. With those guns it may give a FULL fill. Aluminum tanks are about half the price of a 4500 psi carbon fiber tank, known as an SCBA (Self Contained Breathing Apparatus). Most common use ofSCBA’s are firefighters. But there are other users, like airgunners. SCBA’s are about, or less than half the weight of an aluminum tank.
The world learned a lot about carbon fiber this past summer with the Titan submersible. Dismiss all that info as it does not pertain to how common SCBA’s have been safely used for several decades.

For the typical (not Anchutz 10 meter rifles) PCP rifles the full pressure is often above 3000 psi. So an aluminum tank won’t even give one full fill. There are some high pressure aluminums that go to 3500psi but are larger and definitely heavy.
Pretty much everyone would recommend a carbon fiber SCBA for modern PCP use. Just like scuba tanks they do have required hydro tests and in the U.S.A. have a 15 year life.
There are lots of threads here on AGN as far as SCBA info.
Once you decide to go with an SCBA, like scuba, you have choices in sizes (volume) of contained air.
Welcome to the PCP world. I, like many others am addicted to PCP’s.

 

[AlanMcD]

What everyone said above is accurate, but they seem to be forgetting that you already have the SCUBA tanks on hand. Depending on the fill level and the gun you pick, they could get you started just fine, and you might be fine with them for quite a while.

That said, many SCUBA tanks use K-Valves, which are completely different that what any SCBA tank will use - so you will need unique fill devices if you decide to move into the SCBA at some point. The other thing is that you said you have two SCUBA tanks, so you could also cascade fill with them - that lets you get far more fills closer to 3000 psi out of them. You would use a Y connector to connect the two tanks to the gun, then do as much fill as you can from the tank with the lower pressure, then without venting close that valve and fill more with the second higher pressure tank - this lets the higher pressure tank preserve as much air as possible for future fills. Of course this would also mean you need two K valve fill sets to do this.

But you could start with one fill set to decide how you want to do things, and then move forward to either cascade or go a different route later. Of course all this assumes your tanks pass testing and can continue to be filled.

 

[rcs9250]

What everyone said above is accurate, but they seem to be forgetting that you already have the SCUBA tanks on hand. Depending on the fill level and the gun you pick, they could get you started just fine, and you might be fine with them for quite a while.

That said, many SCUBA tanks use K-Valves, which are completely different that what any SCBA tank will use - so you will need unique fill devices if you decide to move into the SCBA at some point. The other thing is that you said you have two SCUBA tanks, so you could also cascade fill with them - that lets you get far more fills closer to 3000 psi out of them. You would use a Y connector to connect the two tanks to the gun, then do as much fill as you can from the tank with the lower pressure, then without venting close that valve and fill more with the second higher pressure tank - this lets the higher pressure tank preserve as much air as possible for future fills. Of course this would also mean you need two K valve fill sets to do this.

But you could start with one fill set to decide how you want to do things, and then move forward to either cascade or go a different route later. Of course all this assumes your tanks pass testing and can continue to be filled.

Very good point.
One of my PCP’s is an Air Arms HFT500 in .177. Its max fill pressure is 190 bar (2755 psi). A 3000 psi cascade would keep you running for a very long time.

Even if you don’t get FULL fills you’ll still get a ton of shots before you have to refill the scuba tanks, you would just get fewer shots per fill.

 

[JimD]

With "free" tanks I think it is worth doing as long as you have a way to fill them. A hand pump would take WAY too long for me to consider it. Even the small portable compressors would probably take over an hour. A Yong Heng would do it in a few minutes. But if you can get fills from a dive shop reasonably, that would be a good way to start out. Saves the expense of the compressor at least initially,

It seems like 250 Bar is the fill pressure of a lot of current PCPs. There are higher and lower, of course. I don't think you can reach that with a SCUBA tank but you don't have to as long as you are prepared to fill more often. My P35s take 250 Bar fills, for instance. But if I fill them to 3000 psi I still get a lot of shots, particularly from the 177. As long as you fill above the regulator (135 bar at most for my P35s) you have shots.

As long as your tanks can be filled above the regulator setting of the PCP you want, they can be useful. A 4500psi SCBA tank is more useful but also costs money. The cascade fill idea already mentioned is a way to get the most out of the tanks you have.