CO2 Filling

CO2 Instructions

These insructions for CO2 are adapted from the supplier of my CO2 filling - contact y2kta at hotmail dot com to purchase if you want them too!

Travel & Storage:  Do not leave filled tanks in direct sunlight.  They can heat up and rupture the burst disc which means they will not hold any CO2 until they are repaired.  Car trunks are also taboo for PB tanks in the summer.  If you are in a car and a CO2 tank begins leaking, OPEN THE WINDOWS!  Remember the risk of suffocation.  And don’t touch a tank that is venting, it could cause severe frostbite.

Tank Maintenance:  Inspect the valve of your tank.  The top lip should not be bent as this may not allow the tank to seal properly.  There is a bolt like device on the side of the valve called the burst assembly.  If this area is leaking slightly, you may be able to stop the leak by gently tightening the bolt.  If the leak does not stop or gets worse, the burst disc needs to be replaced.  Using a valve thread protector is good cheap insurance and most provide storage for an extra o-ring.  Also, put your name or other obvious identifying mark on your tank to keep from getting it switched with someone else’s.  (Good for the rest of your gear as well if you haven’t already done this.)  If you have to remove a tank valve, be sure to empty it completely first.  If the valve is inoperable, remove the burst assembly (gently and in a well ventilated space).  Always use red loctite or comparable when reinstalling a tank valve and let it cure for 24 hours before filling.  This prevents the accidental unscrewing of the tank from the valve.

CO2 Filling 101

To refill paintball tanks you will need the following items:  A Co2 bulk tank, a CO2 fill station, an adjustable wrench large enough to attach the fill station, and a scale to weigh the empty / filled tank.

Bulk Tanks:  You can get these at welding supply shops, medical gas suppliers and soft drink vendors.  Tanks come in 2 types, standard and siphon (also called dip tube) models.  For the smaller sizes, either one will work, but for tanks larger than 50# (weight of CO2, not the tank itself) you will want to get a siphon tube.  Syphon tube tanks supply liquid CO2 when the valve is opened.  Non siphon tanks must be inverted to get liquid CO2 out of them.  YOU DO NOT WANT TO TRY AND INVERT A 50# CYLINDER, THEY WEIGH ABOUT 200 POUNDS PLUS!!!   As a safety precaution, with tanks over 20#, secure them from falling with chain or tie down straps (not bungee cords) to a tree, wall, vehicle, etc.  A falling CO2 tank poses multiple risks of crushing bones, frostbite, etc.  When not in use, always use the protective cap provided with the tank.  Never move a bulk tank without the cap.

A paintball CO2 tank is rated full when it contains 2/3 of it’s volume with liquid CO2.  The ounce rating of the tank refers to the number of ounces by weight that constitutes this fill.  You should completely empty the tank to be filled (this can be done safely on the fill station) and then weigh the empty tank.  I like to mark the empty weights on all my tanks to save time.  Also get in the habit of checking the condition of the tank o-ring before attaching it to the fill station.  Replace it if necessary.

Attaching the fill station:  Secure the bulk tank as described above.  Then remove the valve protector cap and attach the fill station.  Be sure to insert the plastic washer between the bulk tank and the fill station.  (I like to keep a few extra washers in my kit – available where you get the CO2)  Make sure the ball valve(s) on the station are closed.

Filling a Paintball tank:  Check the tank’s o-ring (good time to lube it too) and attach the PB tank to the fill station.  If the PB tank still has CO2 in it, open the dump valve and vent off all the CO2 (THIS MUST BE DONE IN AN OPEN SPACE – CO2 IN A CONFINED SPACE CAN CAUSE SUFFOCATION AND DEATH)  If the PB tank is empty, you will need to chill it first.  This is done by letting in a small amount of CO2 then bleeding it out.  Ideally the PB tank should be about the temperature of a glass of ice water.  If it’s frosted, it’s too cold and may cause an overfill.  (You can pre-chill empty tanks in a cooler to save on CO2.)  Weigh the empty PB tank, fill by opening the fill valve (on a single valve fill station the bulk tank valve is also used as the fill valve) and allow the CO2 to transfer.  Once the flow stops, close the fill valve and re-weigh the tank.  It should be at or under the rated weight of the tank (9oz., 12oz. etc)  Remember if your scale does not have a tare weight zero function, you will have to allow for the weight of the empty tank plus the CO2 fill. (Hint: you can put both empty and filled weights on the tank with a sticker to save time)  If the tank is several ounces less than the desired fill weight, you can bleed some CO2 off and fill again.  This chills the PB tank and lowers the pressure so that more liquid from the bulk tank will flow in.  Once the desired weight is reached, close the fill valve, close the on off valve on the PB tank adapter, and then open the dump valve.  If you overfilled, you can use the dump valve (be sure the fill valve is closed) to bleed off excess CO2 from the PB tank.  Make sure that everyone is clear of the exhaust as it can cause frostbite.  Many players and fields attach an old piece of hose to the exhaust post and channel it to the ground where it is less likely to contact skin.  Once the line is cleared, it is safe to remove the PB tank. 

One special note here.  All new PB tanks have a paint line mark where the valve meets the tank body.  On a few occasions, players were unscrewing their tanks from the markers and didn’t notice that the tank was moving but the valve was not.  The result was the tank  coming off the valve like a rocket and both injuries and fatalities have resulted because of this.  If your tanks don’t have that stripe, put one on and make sure every player looks while removing a tank that the valve is unscrewing as well.

Note tnat in colder climates, CO2 bulk tanks fill more easily if they are stored away from the cold, such as inside a garage, storage room, etc. Cold lowers the pressure in the CO2 tank and decreases the flow significantly.