Reply With QuoteSome people say a pump can cause corrosion inside a steel cylinder due to the air containing moisture. Not sure if the filters on some pumps are effective to cure this. Any comments from people in the know ?
Baz
Registered User
Gents,
Just taken my 300bar cylinder in to my local dive shop to be filled and realised its certificate ran out in Feb 2017. The last time it was filled was Feb 2012 (don't use my FAC Superten that much!) and it has dropped to below 200bar. They wanted £55 for a re-test and £35 to refill (apparently has to be filled/cooled four times from empty) so £90 in total. That would be bad enough but apparently as I haven't got a 'surface valve' on the cylinder the new regulations are that it has to be tested every 2.5yrs - what nonsense! Boy I wish I'd got it filled it in January as it would've cost just a few quid and probably lasted me another 5 years - doh!
So I walked away and thought I'd canvas your opinions as to whether it was now time to spend the money instead towards a pump which will certainly be cheaper in the long run. So any thoughts please on pumps versus cylinders and if I go this route which one, where from and how much are they please?
I look forward to hearing from those with greater knowledge on the subject than me!
Registered User
Some people say a pump can cause corrosion inside a steel cylinder due to the air containing moisture. Not sure if the filters on some pumps are effective to cure this. Any comments from people in the know ?
Baz
BE AN INDEPENDENT THINKER, DON'T FOLLOW THE CROWD
Registered User
That is very expensive.Originally Posted by Dodder
suggest a web search for other providers.
I bought a new 12L 300 bar cylinder, took it to my local RFD filled it for a fiver
Registered ̶D̶i̶a̶n̶a̶ User
If I was a PCP owner this would turn me off a pump
https://youtu.be/KbbUAXjo13M
Registered User
As you don't have a surface use valve fitted the tank has to be treated as any other scuba tank. This means that it has to have the full hydro test every five years (the same as a surface tank) but it also has to have the cheaper visual inspection every 2-1/2 years. If you exceed the 2-1/2 year period, it has to have another hydro test.
You can shop around to get the best price for the test and an air fill is usually included.
I appreciate that it is difficult to fill a 300 bar cylinder at the first attempt but filling it slowly whilst standing it in a tank of cold water should certainly make it possible to achieve it in two attempts. I usually overfill by around 20 bar to allow it to cool back to the required pressure. A £35.00 charge because they can't or won't take the time to do the job properly seems excessive. The would still have similar problems topping up from 170 to 300 bar - how much do they charge for that?
Divers will be bringing cylinders to them with 40 - 50 bar left following a dive and they wouldn't pay £35.00 for a refill. If you are prepared to accept 270 - 280 bar then tell them to fill it once and used the money saved to get a top up when needed.
A dive centre will supply you with dried air which will be much better for your rifle. A pump with a dri-pak may work but it depends upon the quality of the kit. It's your call!
Registered User
im about to buy my first pcp rifle and not having any transport and refill shop 4 miles away,im going to use a pump,im sure if you keep everything clean n do job properly cant see why there should be any problems,but people here will know more about it than me.
Registered User
You can keep everything spotlessly clean but you still have to remove the water vapour from the air that you are pumping into the gun or you will face internal corrosion problems.
All compressors have water traps of varying levels of sophistication to deal with this problem. Diving compressors have a far more sophisticated arrangement than most. Rust flakes inside a tank can shut of a diver's air supply or ruin a regulator.
Last edited by Scubashot; 30-06-2017 at 03:27 PM.
Registered User
Some good reading there,thanks
Registered User
Most guys I know that use a pump wouldn't consider pumping up their dive cylinder with it, they only pump up their buddy bottle and that takes quite a bit of effort. They are alloy though, so no danger of rust in them, but just depends how much unprotected steel there is inside your gun as to whether you'll induce corrosion in it.
Registered User
Part of the test procedure used to be after hydro valve servicing drying and reassembling etc: was fill to working pressure with its working medium ie; gas(Air) , Otherwise how do they know it does not leak at it's working pressure and that used to be part of the test to British standards .
A test with water ( hydro) only tests the pressure vessel and if you are paying out for valve servicing/inspection and refit it must be tested as a complete item otherwise it should not be given back to you as a fully tested and working cylinder and valve assembly.
In my time At MDE i tested over 10,000 cylinders and unless the cylinder came in from a client with no valve fitted ie:Hydo only every cylinder was filled to working pressure and the test and certificate will not be signed for unless it passed a pressure leak test.
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