one of sebs crazy ideas alert ....

[slugger]

You dont' need a check valve - the pump should have one built in.
I used to fill a Gunpower Stealth bottle with a pump and also a best fittings 500cc field bottle neither of which have their own check valve - it was physically hard work but it was possible.

A few observations - it is extremely hard work on the pump and it will generate a lot of heat and moisture. If you do manage to fill the cylinder I think the pump will probably be ruined by the end. You will need to take frequent breaks to let the pump cool down, in reality I think it would probably take a day to fill the cylinder, with rests for you and the pump.

Pumping over 200 bar is much harder than pumping up to 200 bar.

Without blowing my own trumpet I am extremely fit and quite large and strong and filling the 500cc cylinder to 250bar used to make me puff and sweat some and I had to take rest breaks to get the cylinder filled. I really think that you're on a hiding to nothing with this one.

you may be right, but if theres even a chance, i would like to try it...
in theory [if the pump has a check valve like you say] all i would need is a lump of ally or brass with 2 holes drilled next to each other [probe size holes] so that i can fit the pump probe in one, the bottle probe in the other... and a smaller hole at 90 degrees joining the 2 holes [centrally ie between the o-rings of the probes] and then block off the holes entrance........ should be quite easy to make without any fancy tools maybe ?

[slugger]

Fully agree with Biker Bob, the pump would have to be in water to take some of the heat away,an pretty sure the idea is build a machine to do the pumping, i hope,

altho a machine [ive seen em on youtube] would be cool, i kinda wanted to do this by hand....... i could do say 50 pumps per day [as an excersize thing] . so long as i can top-up the bottle between shoots i would be happy...

[Bladerunner too]

im unsure what you meant buddy, elaborate for me ?

The Theoben bottle has a removable neck,the bit that you screw onto to fill, the neck has a ball bearing in to stop the air when the bottle is off the gun, so i thought it would do the same job as when filling ,it would only need a connector on both ends, the normal one that the rapids use an then another connector to you bottle.

[Bladerunner too]

altho a machine [ive seen em on youtube] would be cool, i kinda wanted to do this by hand....... i could do say 50 pumps per day [as an excersize thing] . so long as i can top-up the bottle between shoots i would be happy...

Excellent idea, an get your mates around, Tell them its a new gym machine.

[slugger]

The Theoben bottle has a removable neck,the bit that you screw onto to fill, the neck has a ball bearing in to stop the air when the bottle is off the gun, so i thought it would do the same job as when filling ,it would only need a connector on both ends, the normal one that the rapids use an then another connector to you bottle.

aha, gotcha.... but i was kinda hoping i could avoid undoing/ptfe tape/doing back up various fittings every time i want to fill.... if my above lump of brass idea is workable then i simply plug the existing fill probes into 2 holes, simples

[slugger]

Excellent idea, an get your mates around, Tell them its a new gym machine.

i once told the missus her ass was getting a bit saggy told her squats and pushes would be a good excersize.... lent her the pump trouble is shes not heavy enough to pump much past 100 bar

[Bladerunner too]

Take ten minutes , going to take Two weeks to fill,,, This comment is just playing.

[richierich]

Daft idea.

Given the heat the pump would generate, it would likely take a fair few hours having to stop and wait for it to cool. You'll end up knacking the pump, so don't bother.

If you want to fill it yourself, buy a compressor

[GrahamHenderson]

I have a Hills pump with drypack, and often pump my 3litre cylinder from 160bar to 210bar,
best done outside in a breeze
... Its not difficult you bunch of wimps!!

[slugger]

some of you guys are [i think] skimming over the point of a few pumps / day ..... bit of excersize , not enough to build up much heat , done indoors in a dry atmoshpere [plus the pump has a dry pack]
im not saying its going to be easy, but i was thinking little and ofter kinda thing... so long as [for example] i can get my bottle from 150 bar back to 200+ bar in a week, then thats all i would need

[Ieazo]

Moisture getting into the bottle is my issue with this, forget how long pumping would take and whether it is done all at once or a wee bit at a time.

Surely if you decide to do this you should have your bottle hydrostat tested at 2 year (like divers do?) intervals as the moisture in the bottle may corrode and weaken the bottle. I don't fancy your chances of saving much cash what with paying for hydrostats, possibly/probably blasting the corrosion and finally buying a new dive bottle at more frequent intervals.........of course it depends on how often you need to fill the bottle based on how much shooting you do.

Cheaper all round to just buy a springer so you can save some air and make it last longer therefore decreasing the frequency with which the bottle requires refilling.

Hth

[richierich]

some of you guys are [i think] skimming over the point of a few pumps / day ..... bit of excersize , not enough to build up much heat , done indoors in a dry atmoshpere [plus the pump has a dry pack]
im not saying its going to be easy, but i was thinking little and ofter kinda thing... so long as [for example] i can get my bottle from 150 bar back to 200+ bar in a week, then thats all i would need

If you're prepared to do that, why not just fill the rifle from the pump?

[slugger]

because if i go for a days shooting, i might get through 4 fills .... take the bottle for plinking, top it up during the week when not shooting

[Ouch!]

Just move closer to the dive centre.
We are none of us getting any younger.

Ouch!

[slugger]

you lot have no sense of adventure