Indians For Guns

Gurus.

I did not find a thread detailing the subject of Air tanks for refilling our PCP's. An afternoons worth of googling tossed up prices ranging from 20k to about 4k, different capacities, valves, adapters ... the variables abound!

Gurus please shed some light on it - Perhaps this can be a one stop thread/knowledge base on this subject.

1. Is it necessary to buy a SCUBA tank - or will any industrial gas tank suitable for compressed air or 'ZERO AIR' as in tech parlance - do?

2. What should be the specs - in terms of the Min and Max operating pressure considering the application (Walthers are 300BAR guns)

3. What type of Nozzle/adapters should it have (the technical name and options)

4. Steel or Aluminium.. seamless or ....

5. Used or New - what is the life expectancy of each.

6. Precautions while buying used.

7. Apparently Hydrostatic testing is mandatory by law every five years for new. Should one insist on this BEFORE picking up used ones - as well as revising the periodic testing interval?

8. Where will one get DRY air (cause moisture will definitely cause the internals of both the tank and the gun to corrode).

9. Refilling instructions/precautions

10. How many refills can one get - say from a 5-6ltr tank.

11. General storage, care and upkeep/periodic maintenance.

12. Recommended dealers if any.

you can use SCUBA or SCBA cyls. SCBA are also compressed air tanks used by fire fighters.
-Any high pressure scuba tank has to be seamless.
-A 300 bar tank is tested to 450 bar.
-Test pressure, working pressure details, Manufacture date, OD & ID of bottle, Last test done, Serial number details should be embossed on the bottle neck just below the fitting.
-Make sure you get paper work for the above from the seller.
-If the bottle goes underwater the pressure test is done every year. But if used for shooting you can get the test done every 2 years to be on the safe side. Hydro test can be done every 5 years. This way you will be in peace & extra safe.
- The compressor should have water traps & extra filter to absorb moisture. Please be aware a little bit of moisture will still be there. To play safe Charge your tank & gun with air but time to time use nitrogen too as nitrogen being dry & inert will eliminate any moisture in the bottle & gun. Beware nitrogen will also dry seals & "o"rings so keep the parts well lubricated.
- depending on the size 5-6 liter you will get more than 35 fills.
- when filling a bottle make sure it is put in a drum full of water ( cold if possible) as when the bottle is charged it gets very hot. This way you don't loose any pressure when the bottle cools & will not explode if too hot. Do whip lash charging hose etc for your own safety as they can burst & inflict grave injuries to a person.
- do not keep a bottle charged for long. charge ...use then de-pressurise the bottle to about 20-50 psi. Store the bottle in cool place away from electrical s & fire hazard area. If you have a very strong steel box to store the bottle nothing to beat it.
-Din fittings are common on SCUBA bottles.
- you can order them from numerous diving sites, Amazon.com, Air guns of arizona, pyramid air, Delhi based uttam air products.
-dealers..I know a couple in mumbai.