TargetTalk

I have borrowed an air pistol and now both the cylinders are below limits - I have access to a Gehmann Hand Pump and the adapter for filling that comes with the pistol.

Is there only one adapter for both scuba tank filling and hand pump filling?
What is the procedure - fit adapter - fit cyclinder - close water drain - pump like mad?

Seems with all connected the guage goes upto 100 bar then nothing happens?

Thanks
An Air Pistol Noob

I have a Hill pump, and your "pump process" sounds right, except I close the water trap first. Otherwise my cylinder will just vent itself. There may be something weird about the Gehmann pump relative to the Hill that requires different/additional steps.

bump

Air Pistol Noob,

I have the Hill pump, however, I open the water drain after filling the cylinder to purge moisture collected while filling. Mine doesn't empty the cylinder at that time, just the pump and hose. I fill mine in my dehumidified basement, so don't see any moisture anyway.

I don't agree with pumping like mad. I like to pump at a leisurely pace to avoid generating a lot of heat in the pump.

I have no experience with the fittings question, sorry.
Ben

Back to your original question re the same fitting for pump and scuba tank. The answer is yes and no.
The Morini fitting should screw into the pump and a scuba tank - if the tank has the correct valve fitting. If the scuba tank is a 200bar tank then fittings are widely available and your dive shop can probably accommodate. If it is 300 bar tank, then normally you will need a fill adapter which has a longer thread.
(Yes, I know the Morini cylinder is only rated to 200 bar but I know some who have acquired some second hand 300 bar scuba tanks but only have them filled to just over 200bar.)

ColinC wrote:Back to your original question re the same fitting for pump and scuba tank. The answer is yes and no.
The Morini fitting should screw into the pump and a scuba tank - if the tank has the correct valve fitting. If the scuba tank is a 200bar tank then fittings are widely available and your dive shop can probably accommodate. If it is 300 bar tank, then normally you will need a fill adapter which has a longer thread.
(Yes, I know the Morini cylinder is only rated to 200 bar but I know some who have acquired some second hand 300 bar scuba tanks but only have them filled to just over 200bar.)

I have 300 bar (4500 psi) tank.

1st - It's not SCUBA tank, it's SCBA tank - No "U" means it's not for underwater using - fire departments or rescue.

2nd - It has different tread - it’s neither the 200 DIN (SCUBA) nor 300 DIN. It has CGA 347 tread fitting and K yoke connector cannot be used because it only for 200 bar (3000 psi) and under.

3rd - Some SCBA shop can fill it, but they do it only up to 4000-4200 psi. Any way it’s better than start from 3000 psi and each time go down.

I have a lot of info about it. PM me if you need to know more about it.

Thanks,
Strannik.

Gwhite wrote:I have a Hill pump, and your "pump process" sounds right, except I close the water trap first. Otherwise my cylinder will just vent itself. There may be something weird about the Gehmann pump relative to the Hill that requires different/additional steps.

Then I make the assumption that you have a Steyer and not a Morini?
With a Steyer you must turn the tube one turn before letting the moist out
Kent

I actually have both. You are correct, I unscrew the cylinders slightly so the cylinder valve is closed and they are no longer open to the pump. Then I open the moisture trap. Air pistol is mostly a winter sport for me, and I haven't used my pump in quite a while.

1st - It's not SCUBA tank, it's SCBA tank - No "U" means it's not for underwater using - fire departments or rescue.

Call it what you like. The tank I am talking about is a SCUBA tank, out of date for underwater breathing which can be purchased cheaply from dive shops, relabelled "Not for breathing" but still refillable for non breathing purposes such as air pistol for several years before having to be checked and recertified.