Fill A Co2 Tank In Paintball

CO2 cylinders are the force behind paintball markers.

CO2 and compressed air are the two major propellant sources used in the sport of paintball. These gases are housed in special tanks or cylinders that attach to the paintball marker to shoot a single paintball each time the operator squeezes the trigger. Filling the tanks is not overly complicated but can be dangerous if not done using the proper techniques. Safety glasses and specialized tools should always be used to avoid accidents.


1. Attach the refill kit to the bulk CO2 tank using the O-Ring seal and a wrench to tighten the assembly. An airtight seal must be achieved.

2. Set all valves on both the bulk CO2 tank and the refill kit to the “Off” position.

3. Use the nozzle at the end of the fill hose to attach the paintball CO2 tank to the refill kit.

4. Attach the hanging scale to the bulk CO2 tank via the top hook, and hang the paintball CO2 tank from the bottom hook.

5. Open the “Bleed” valve to purge all of the CO2 inside of the paintball tank. Close the valve once the tank is empty.

6. Adjust the scale’s unit of measure to ounces. See the user’s manual for specific instructions if necessary.

7. Open the main valve on the bulk tank and the “Cut Off” valve on the refill kit to fill the tank. The tank will only fill halfway the first time because of the physics of pressure and temperature.

8. Close the bulk tank’s main valve and the refill kit’s “Cut Off” valve.

9. Open the “Bleed” valve on the refill kit to purge the paintball tank of all CO2 once again. A slight frost will appear on the outside of the tank, indicating the inside temperature has been greatly reduced. This allows the tank to achieve maximum fill.

10. Close the “Bleed” valve, and open the bulk tank main valve and the refill kit’s “Cut Off” valve to begin the fill process anew.

11. Monitor the hanging scale readout, and stop the fill process at one ounce below the tank’s advertised maximum capacity. This is a safety precaution that takes into account the expansion and contraction of gases at different altitudes and pressures.

12. Return all valves to the “Off” position, and unhook the paintball tank from the refill kit and bulk tank.