Filling CO2 Tanks 101

[TimmyMac1]

Mac1 CO2 Transfer adapters are $25. This can be put on ANY master tank or larger CO2 Tank and you can fill smaller tanks directly with No hose or bleeder system.

Always leave a small amount of residual CO2 Gas in tanks at all times. The less atmosphere inside tanks the better.
Install adapter on Master Tank(brass nut to tank valve) and snug it. Blow thru it by opening tank valve till you see liquid start to flow(specific to syphon type tanks) or just blow some gas if it is a Non-Syphon tank. On a Non-Syphon Type tank before you make transfers the tank needs to be inverted to make sure you are transferring liquid. If you are transferring from a Pin valve type tank the Black Side of adapter needs to go on the Pin Valve side.
Open valve on small tank and dump what it has in it with the valve pointing up. Note tanks empty weight or Tare your scale for the tanks weight Empty.
Install small tank on the black side of the adapter with valve open on small tank.
If it got frosty from dumping the CO2 out it is cold enough to refill already and all you need to do is transfer gas to it till it goes from Frosty to wet. You can get the tank(s) cold enough by putting them in the freezer for 20 minutes or the fridge overnight.
You can use CO2 to chill the tank by filling it for a few seconds from the master tank then closing the master tank valve, leaving the small tanks valve open, you then loosen the brass nut from the master tank to let the small tanks CO2 bleed down. This will create a chill/frost on the small tank. The moment you see the hazy chill evident the tank is cold enough and you want to stop the bleed by retightening the brass nut.
Open the Master tanks valve. Transfer of gas is complete the moment you see the receiving tank go from frosty to wet. Turn the valve off on the master tank and small tank simultaneously when you see the thermal transfer occur(backing the pin valves out of the black adapter side one turn turns the pin valve off).
If you overfill the tank it needs to be dumped out or used immediately before it comes to room temperature. Remove the small tank from the adapter and gas in the adapter will vent when you back tank out. Weigh the tank to make sure the Tank is not overfilled and leak check the valve and pressure relief to make sure the tank isn't leaking. Inspect Orings for abuse (replace as required) & refit protective caps to eliminate damage to oring grooves and threads.
Always be careful, wear protective eyewear and do not take air or CO2 pressure lightly. Used correctly it can be a source of very low cost shooting enjoyment once you have all the gear in place. a 20 lb CO2 tank will give up to 20,000 shots on a $20 CO2 fill. It costs about $100-125 at the local welding supply, industrial gas place or beverage distributor.

Have fun and be safe. Mac1 has always been the Bulk fill CO2 place and we were the ones that started the whole LD hangy tank thing.